JP4398225B2 - Semiconductor device - Google Patents

Description

The present invention relates to semiconductor equipment and, more particularly, to a technique effectively applied to a chip-stacked type semiconductor device having a plurality of semiconductor chips.

In a conventional chip stacked type semiconductor device (multi-chip module), a chip in which a dynamic random access memory (DRAM) is formed and a flash memory are formed among three chips mounted on the main surface of the package substrate. Each of the chips is electrically connected to the wiring of the package substrate through Au bumps, and a chip on which a high-speed microprocessor is formed is mounted on the two chips. Is electrically connected to the bonding pad of the package substrate (see, for example, Patent Document 1).
International Publication Number WO 02/103793 A1 (FIG. 2)

  A semiconductor device (multi-chip) having a structure in which a semiconductor chip is flip-chip connected to the main surface of the wiring board, another semiconductor chip is stacked on the semiconductor chip, and the upper semiconductor chip is wire-bonded to the wiring board. Modules, multi-chip packages, etc.) are provided with wire bonding pads (metal fine wire connection electrodes) arranged on the periphery of the main surface of the wiring board, and the flip chip lands (flip chip electrodes) Is provided.

  In the assembly of a chip-stacked semiconductor device having such a structure, when the electrolytic plating power supply wiring is formed outside the product area of the multi-chip substrate, the flip chip land and the power supply wiring are independent of each other. It is difficult to provide wiring to connect.

  On the other hand, stacked semiconductor devices such as multichip packages are often multifunctional and high-density mounting, and a large number of solder ball connection lands (external terminal mounting electrodes) are connected to the back surface of the wiring board for connecting external terminals. ) Are arranged at a narrow pitch.

  As a result of studying further increase in pin count (narrow pitch) in a chip stacked type semiconductor device, the present inventor has found the following problems.

  That is, if the diameter of the solder ball connection land is further reduced by increasing the number of pins, there is a problem that the margin of the connection force between the solder ball and the land is reduced to cause connection failure between the two.

  Even if electrolytic plating is formed on the lands to strengthen the connection between the solder balls and the lands, the number of wires that can be placed between the lands is very large because the number of pins reduces the pitch between the lands. The problem is that it is difficult to draw out the electroplating power supply wiring outside the product area for all the lands.

An object of the present invention is to provide a semiconductor equipment to reduce the number of pins.

Further, another object of the present invention is to provide a semiconductor equipment to improve the reliability.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

That is, the present invention provides a first main surface, a plurality of wirings formed on the first main surface, a plurality of bonding pads formed on the first main surface, and a plurality of flips formed on the first main surface. tip electrode, the first back surface opposite to the first major surface, and a plurality of external terminal mounting electrodes formed on the first back surface, and a wiring substrate comprising a wiring layer of six layers, the second main A first semiconductor element formed on the second main surface, a plurality of first electrodes formed on the second main surface, and a second back surface opposite to the second main surface, such that the second main surface opposed to the first main surface of the wiring substrate, a first semiconductor chip that is flip-chip connected to the wiring board of the first main surface through the bump electrodes of the multiple, A third main surface, a second semiconductor element formed on the third main surface, and a plurality of second electric devices formed on the third main surface. The second back surface of the first semiconductor chip has a pole and a third back surface opposite to the third main surface, and the third back surface faces the second back surface of the first semiconductor chip. A plurality of wires that electrically connect the second semiconductor chip disposed on the back surface, the plurality of second electrodes of the second semiconductor chip, and the plurality of bonding pads of the wiring board corresponding thereto. When, wherein the plurality of external terminals mounted respectively on the plurality of external terminal mounting electrodes of the wiring board, the plurality of bonding pads are formed on the first layer of the plurality of wiring layers, wherein The plurality of external terminal mounting electrodes are formed in a sixth layer of the plurality of wiring layers, and each of the plurality of bonding pads is connected to a first power supply wiring for electrolytic plating, External terminal tower Each of the electrodes has a second power supply wire electroplating are connected to the respective surfaces of said plurality of bonding pads and the plurality of external terminal mounting electrodes are plated film nickel alloy is formed The first power supply wiring is formed in the first layer of the plurality of wiring layers, and the second power supply wiring is formed in the fifth and sixth layers of the plurality of wiring layers. Each one is formed.

  Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  In a chip stacked type semiconductor device, a nickel alloy plating film is formed on each surface of the metal thin wire connecting electrode on the main surface of the wiring board and the external terminal mounting electrode on the back surface, and is connected to the plating film of the external terminal mounting electrode. Electrolytic plating power supply wiring is formed in the inner layer of the wiring board, so that the external terminal mounting electrodes can be arranged at a narrow pitch on the back surface of the wiring board, and the number of pins of the semiconductor device can be increased. Can do.

  In the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

  Further, in the following embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments, but they are not irrelevant to each other unless otherwise specified. The other part or all of the modifications, details, supplementary explanations, and the like are related.

  Also, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), particularly when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and it may be more or less than the specific number.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

(Embodiment)
1 is a cross-sectional view showing an example of the structure of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a plan view showing the structure of the semiconductor device shown in FIG. 1 through a sealing body, and FIG. 4 is a block diagram showing an example of the system of the semiconductor device shown in FIG. 1, and FIG. 5 is a multi-piece substrate (wiring board) used for assembling the semiconductor device shown in FIG. ), A plan view of the fifth and sixth layers, FIG. 6 is a manufacturing process flow chart showing an example of a method of forming each electrode of the wiring board shown in FIG. 5, and FIG. FIG. 8 is a partially enlarged cross-sectional view schematically showing an example of the structure of the semiconductor device shown in FIG. 1. FIG. 8 is a manufacturing process flow chart showing an example of a method for forming a high-precision precoat on the flip chip electrode of the wiring board shown in FIG. Is the wiring board of the semiconductor device shown in FIG. FIG. 10 is a partially enlarged cross-sectional view showing a structure of a flip-chip electrode according to a modification of the wiring board of the semiconductor device shown in FIG. 1, and FIG. FIG. 13 is a partially enlarged cross-sectional view showing an example of the structure of the external terminal mounting electrode in the wiring board of the semiconductor device shown in FIG. 1, and FIG. 13 and FIG. FIG. 15 is a plan view showing the structures of the outermost layer and the lowermost layer before etch back in the method of removing the power supply wiring of the wiring board according to the modification of the embodiment of the present invention, and FIG. It is a top view which shows the structure of the outermost layer after back, and the lowest layer.

  The semiconductor device of the present embodiment shown in FIGS. 1 to 3 is of a chip stack type in which three semiconductor chips (first, second, and third semiconductor chips) are mounted on a wiring board. A semiconductor device in which a plurality of semiconductor chips are mounted on the same wiring board is referred to as a multichip module (MCM), and an MCM having a structure in which semiconductor chips are stacked is referred to as a stack structure MCM. In the semiconductor device of the present embodiment, among the three semiconductor chips, the first semiconductor chip is the microcomputer chip 2, the second semiconductor chip is the memory chip 3 such as Flash Memory, and the third semiconductor chip. The chip is a memory chip 4 such as a DRAM (Dynamic Random Access Memory), and thus a semiconductor device in which the memory chips 3 and 4 and the microcomputer chip 2 for controlling them are mounted on the same wiring board is system-in-package. Called (SIP10).

  The detailed structure of the SIP 10 of the present embodiment shown in FIGS. 1 to 3 will be described. The main surface 1a has a plurality of wirings and a plurality of electrodes (bonding pads 1d and flip-chip electrodes 1e), and the main surface 1a An SIP substrate 1 which is a wiring substrate having a plurality of bump lands (external terminal mounting electrodes) 1c formed on the opposite back surface 1b, a semiconductor element and a plurality of pads (electrodes) 2a on the main surface 2b, and a SIP A microcomputer chip 2 which is a first semiconductor chip flip-chip connected to the main surface 1a of the substrate 1 via a gold bump (bump electrode) 1i, and a semiconductor element and a plurality of pads (electrodes) 3a on the main surface 3b. And a memory chip 3 as a second semiconductor chip disposed on the back surface 2c of the microcomputer chip 2 via a die-bonding material 9 (see FIG. 7), and a semiconductor element on the main surface 4b. And a plurality of pads (electrodes) 4 a and a memory chip 4, which is a third semiconductor chip disposed on the back surface 2 c of the microcomputer chip 2 via a die bond material 9, and a main surface 3 b of the memory chip 3. The plurality of pads 3a are connected to the bonding pads 1d on the main surface 1a of the SIP substrate 1 corresponding thereto, and the plurality of pads 4a on the main surface 4b of the memory chip 4 are connected to the main pads 1a of the SIP substrate 1 corresponding thereto. A plurality of fine metal wires 5 for connecting the bonding pads 1d on the surface 1a, a microcomputer chip 2, the memory chips 3 and 4, and a sealing body 6 for resin-sealing the plurality of wires 5; The solder ball 8 is a plurality of external terminals mounted on the bump land 1c on the back surface 1b.

  Furthermore, in the SIP 10, as shown in FIG. 7, each of a bonding pad (metal thin wire connecting electrode) 1d on a plurality of electrodes on the main surface 1a of the SIP substrate 1 and a bump land (external terminal mounting electrode) 1c on the back surface 1b. A nickel-gold alloy plating film 1g is formed on the surface of the substrate, and an electroplating power supply wiring 1h connected to the plating film 1g of the bump land 1c on the back surface 1b is connected to the SIP substrate 1 ( It is formed in the inner layer of the multi-piece substrate 11).

  That is, as shown in FIGS. 1 and 2, the SIP 10 of this embodiment includes a microcomputer chip 2 that is flip-chip connected to a SIP board 1 that is a wiring board, and memory chips 3 and 4 that are wire bonded. It is a chip stacked type semiconductor device in which memory chips 3 and 4 are stacked on a microcomputer chip 2. On the back surface 1b of the SIP 10, as shown in FIG. 3, a plurality of solder balls 8 are provided on the bump lands 1c as external terminals.

  At that time, in the SIP substrate 1, a nickel-gold alloy plating film 1g is formed on the surface of the bump land 1c (the base is the copper pattern 1k shown in FIG. 6) on the back surface 1b, and this plating film 1g is formed. By forming the electroplating power supply wiring 1h used in the above in the inner layer of the SIP substrate 1, an empty space on the back surface 1b for increasing the number of pins can be secured.

  Furthermore, since the nickel-gold alloy plating film 1g is formed on the surface of each bump land 1c, the connection strength between the bump land 1c and the solder ball 8 can be increased. As a result, the diameter of the bump land 1c is further increased. It is possible to reduce the pitch and to reduce the pitch of the bump land 1c.

  Thereby, the number of pins of the SIP 10 can be increased.

  Next, the control relationship between the microcomputer chip 2 and the memory chips 3 and 4 in the SIP 10 of the present embodiment will be described.

  The memory chips 3 and 4 are controlled by the microcomputer chip 2. The functions of the microcomputer chip 2 and the memory chips 3 and 4 and the pin configuration associated therewith will be described with reference to FIG.

  Here, according to the embodiment, a case where the memory chip 3 in which the flash memory is formed and the memory chip 4 in which the DRAM is formed will be described, but the number and types of the memory chips 3 and 4 are described in this example. It is not limited to.

  The microcomputer chip 2 inputs and outputs data between an external LSI (Large Scale Integrated circuit) provided outside the system and the memory chips 3 and 4 provided inside the system. For this purpose, the microcomputer chip 2 converts a logical address (external address) for external interface into an address for flash memory or DRAM.

  When the microcomputer chip 2 plays such a role, the microcomputer chip 2 needs pins constituting an external interface in addition to the number of pins necessary for the interface between the microcomputer chip 2 and the memory chips 3 and 4. Therefore, the microcomputer chip 2 has a larger number of pins than the memory chips 3 and 4 by the number of pins necessary for the external interface.

  The microcomputer chip 2 of the present embodiment has, for example, a PCI bus or a USB bus as an external interface. Thus, when the microcomputer chip 2 has a plurality of types of external interfaces, the number of pins required for the microcomputer chip 2 is increased compared to the case where the microcomputer chip 2 has one type of external interface.

  When a plurality of types of memory chips 3 and 4 are provided such as a flash memory and a DRAM, the number of pins required for the memory interface of the microcomputer chip 2 is larger than the number of pins included in the interface of each memory chip.

  As described above, when the memory chips 3 and 4 have a plurality of types of memories, the configuration of the memory interface of the microcomputer chip 2 may be larger than the number of pins of the interface included in each of the memory chips 3 and 4. is there.

  In addition, the microcomputer chip 2 may have various circuits other than the MPU. In this case, a larger number of pins is required to supply a stable power source to each circuit. For example, the microcomputer chip 2 of the present embodiment has an A / D, D / A conversion circuit, and a PLL circuit. Such A / D, D / A conversion circuit and PLL circuit can be a power supply noise source and have a property of being susceptible to external power supply noise, and therefore has a power supply pin separated from the MPU. As a result, the number of pins of the microcomputer chip 2 further increases. Further, the microcomputer chip 2 has an external interface circuit, but in order to realize stable signal amplification in the external interface circuit, a power supply pin independent of an internal circuit such as an MPU is required. This also increases the number of pins of the microcomputer chip 2.

  Therefore, for example, the number of pads 4a of the memory chip 4 is 70 (terminals and pins), the number of pads 3a of the memory chip 3 is 56, and the total is about 126, whereas the gold of the microcomputer chip 2 is The number of bumps 1i is 272, and the microcomputer chip 2 has a multi-port structure including various interfaces with the outside of the system in addition to the interface with the inside of the system (memory chips 3, 4 and the like). Therefore, the number of pins is much larger than that of the memory chips 3 and 4. As a result, in the case of the SIP 10 of the present embodiment, about 400 external terminals are required in total, but the power supply wiring 1h of each bump land 1c is routed in the inner layer of the SIP substrate 1, The number of pins can be increased, and even when the number of pins is increased, the pitch of the bump lands 1c can be reduced.

  The microcomputer chip 2 is flip-chip connected to the SIP substrate 1, and a large number of flip-chip electrodes 1 e are formed on the main surface 1 a of the SIP substrate 1, but the bonding pad 1 d connected to the wire 5 is the main surface. Whereas the flip chip electrode 1e is disposed near the center of the inner side of the flip chip electrode 1e, the power supply wiring 1h connected to each bump land 1c on the back surface 1b is disposed on the main surface 1a side. It is very difficult to pull out outward on the main surface 1a side through each flip chip electrode 1e. Therefore, it is very effective to form the power supply wiring 1h in the inner layer of the SIP substrate 1 as in the SIP 10 of the present embodiment.

  As shown in the cross-sectional view of FIG. 5, the SIP substrate 1 used in the SIP 10 of the present embodiment has wiring formed on both front and back surfaces of the core portion 1q, which is the base substrate, and is further insulated by a build-up manufacturing method on both sides. This is a multilayer wiring board formed by alternately laminating layers 1w and conductive layers (wiring layers). In the case of the example shown in FIG. 5, a multi-chip substrate (wiring substrate) 11 having six wiring layers, and a package assembled using the multi-chip substrate 11 has a six-layer wiring layer. This is the SIP 10 shown in FIG.

  In the SIP substrate 1, the terminals on both the front and back sides of the core portion 1q are connected by a base via 1s as shown in FIG. Further, an internal wiring 1r is formed in each wiring layer.

  Note that the SIP substrate 1 incorporated in the SIP 10 of the present embodiment is assembled using the multi-cavity substrate 11 shown in FIG. That is, the product region 21 is a SIP 10 region, and a cutting portion 20 that is cut when separated into pieces is formed outside the product region 21. Accordingly, the product region 21 of the multi-chip substrate 11 corresponds to the SIP substrate 1, but the power supply wiring 1h for forming the nickel-gold alloy plating film 1g of the bump land 1c on the back surface 1b on the inner layer thereof. Is formed. In FIG. 5, the bump land 1 c on the back surface 1 b and the through-hole wiring 1 u of the cutting part 20 are connected via the fifth-layer power supply wiring 1 h. Alternatively, the bump lands 1c at positions apart from the sixth layer are connected to each other via the via 1t of the cutting portion 20 in the sixth layer and the power supply wiring 1h in the fifth and sixth layers.

  Further, the bump land 1c arranged relatively near the center in the bump land row is connected to only the power supply wiring 1h, and the single power supply wiring 1h connected to the bump land 1c is drawn to the outside. Some of them are

  In this manner, in the state of the multi-chip substrate 11, all the bump lands 1c on the back surface 1b are independent, or the inner layer power supply wiring 1h, or the power supply wiring 1h of the cutting part 20 and the through-hole wiring 1u of the cutting part 20 are used. In this state, power is supplied to the plating film 1g of each bump land 1c so that a nickel-gold alloy plating film 1g is formed. It is formed.

  Further, by cutting the cutting portion 20 by dicing or the like when the SIP 10 is assembled into individual pieces, each bump land 1c is insulated and is not electrically connected between the lands (however, the land for GND is provided). In the case of a common electrode such as, it may be connected).

  Further, in the SIP substrate 1 of the SIP 10 of the present embodiment, as shown in FIG. 7, since the flip chip connection of the microcomputer chip 2 is a connection between the gold bump 1i and the solder, the main surface 1a of the SIP substrate 1 is Each of the plurality of flip chip electrodes 1e is not subjected to electrolytic plating. Therefore, the power supply wiring 1h is not connected to each flip chip electrode 1e.

  Further, since a gold wire is used for the wire 5 which is a thin metal wire, the surface of the bonding pad 1d on the main surface 1a side of the SIP substrate 1 to which the wire 5 is connected is similar to the bump land 1c on the back surface 1b. Further, a nickel-gold alloy plating film 1g is formed to increase the connection strength between the wire 5 of the gold wire and the bonding pad 1d.

  As shown in FIG. 2, the bonding pads 1d are arranged along the peripheral edge of the main surface 1a, so that it is easy to draw the power supply wiring 1h outside the product region 21. .

  An underfill resin 7 is injected between the microcomputer chip 2 and the main surface 1a of the SIP substrate 1, that is, in the flip chip connection portion, to protect the flip chip connection portion.

  According to the SIP 10 of the present embodiment, the power supply wiring 1h for electrolytic plating connected to each bump land 1c on the back surface 1b of the SIP substrate 1 is formed on the inner layer of the SIP substrate 1, so that the back surface for increasing the number of pins can be obtained. An empty space of 1b can be secured.

  Furthermore, since a nickel-gold alloy plating film 1g is formed on the surface of each bump land 1c formed with a copper pattern 1k (see FIG. 6) as a base, nickel (Ni), tin (Sn), and nickel Since the bonding force at each interface of copper (Cu) is stronger than the bonding force at the interface between tin and copper, the connection strength between the bump land 1c and the solder ball 8 can be increased.

  As a result, the diameter of the bump land 1c can be further reduced, and the pitch of the bump land 1c can be reduced, and the number of pins of the SIP 10 can be increased.

  Further, by forming a nickel-gold alloy plating film 1g on the surface of the bump land 1c on the back surface 1b of the SIP substrate 1, the connection strength between the bump land 1c and the solder ball 8 can be increased. In the future, even when the solder of the solder balls 8 is made lead-free, it is more possible to increase the connection strength between the bump lands 1c and the solder balls 8 by forming a nickel-gold alloy plating film 1g on the surface of the bump lands 1c. It is effective.

  Therefore, even if the land area is reduced by increasing the number of pins, it is possible to reduce the occurrence of poor connection between the solder ball 8 and the bump land 1c. As a result, the reliability of the chip-stacked SIP 10 can be improved.

  Furthermore, since the occurrence of poor connection between the solder balls 8 and the bump lands 1c can be reduced, the yield of the SIP 10 can be improved.

  Next, a method for forming each electrode of the SIP substrate 1 used for assembling the SIP 10 of the present embodiment will be described with reference to the schematic diagram shown in FIG.

  First, a plurality of bonding pads 1d, electrolytic plating power supply wirings 1h (see FIG. 5) and flip chip electrodes 1e connected to the bonding pads 1d are formed on the main surface 1a of the SIP substrate 1 by a copper pattern 1k. A plurality of bump lands 1c are formed on the back surface 1b of the SIP substrate 1 by the copper pattern 1k, and an electroplating power supply wiring 1h connected to the bump lands 1c is formed in the inner layer to complete the Cu wiring in step S1.

  Thereafter, only the plurality of flip chip electrodes 1e are covered with a resist film 1v, which is an insulating film, with the resist in step S2. At this time, the bonding pad 1d on the main surface 1a and the bump land 1c on the back surface 1b are exposed.

  Then, electrolytic Ni—Au (gold) plating shown in step S3 is performed to form a nickel-gold plating film 1g on the bonding pad 1d on the main surface 1a and the bump land 1c on the back surface 1b. That is, in a state where the flip chip electrode 1e is covered with the resist film 1v, power is supplied through each power supply wiring 1h to form a nickel-gold plating film 1g on the surfaces of the bonding pad 1d and the bump land 1c. .

  Thereafter, only the flip chip electrode 1e is exposed by the resist in step S4, and the bonding pad 1d and the bump land 1c are covered with the resist film 1x.

  Thereafter, solder pre-coating shown in step S5 is performed. That is, with the bonding pad 1d and the bump land 1c covered with the resist film 1x, the solder precoat 1j is formed on the surface of the flip chip electrode 1e, and the surface of the flip chip electrode 1e is covered with a thin solder film.

  Thereafter, the resist film 1x shown in step S6 is removed.

  Thus, each electrode of the SIP substrate 1 is formed. As shown in FIG. 7, in assembling the SIP 10, the flip chip electrode 1e is flip-chip connected to the microcomputer chip 2 via the gold bump 1i, and the bonding pad 1d Is connected to the wire 5 which is a gold wire by wire bonding, and the bump land 1c is connected to the solder ball 8 respectively.

  When the solder precoat 1j is formed on the surface of the flip chip electrode 1e, it is necessary to form a solder film with high accuracy so as to correspond to the narrow pitch of the flip chip electrode 1e. Therefore, as shown in step S11 of FIG. 8, first, the copper pattern 1k of each flip chip electrode 1e is formed, and then the chemical treatment of step S12 is performed. That is, an adhesive film 1n serving as an adhesive is formed on the copper pattern 1k of the flip chip electrode 1e.

  Thereafter, the solder powder 1m is adhered on the adhesive coating 1n by the powder adhesion in step S13. After the solder powder is adhered, the flux 1p is applied and covered on the solder powder 1m by the flux application in step S14. Reflow of S15 is performed. That is, by heating the copper pattern 1k covered with the solder powder 1m and the flux 1p, the solder is melted to form the solder precoat 1j. In this way, the solder precoat 1j is formed with high accuracy.

  In addition, as a method of forming the solder precoat 1j with high accuracy, a method of forming an alloy having a solder component by substitution reaction with copper (Cu) may be used.

  Next, the manufacturing method of SIP10 of this Embodiment is demonstrated.

  First, in the product region 21 shown in FIG. 5, the main surface 1a as shown in FIG. 6 has a plurality of wires, a plurality of bonding pads 1d, and a plurality of flip chip electrodes 1e, and a plurality of flip-chip electrodes 1e on the back surface 1b. A bump land 1c is provided. Further, a plating film 1g of nickel-gold alloy electrolytic plating is formed on the surface of each of the bonding pad 1d and the bump land 1c, and solder is formed on the surface of the flip chip electrode 1e on the main surface 1a. A multi-piece substrate (wiring substrate) 11 shown in FIG. 5 on which the precoat 1j is formed is prepared.

  In the multi-chip substrate 11, the power supply wiring 1 h, the through-hole wiring 1 u, the via 1 t, and the like that electrically connect the plurality of bump lands 1 c are formed in the cut portion 20 outside the product region 21. Yes.

  On the other hand, a microcomputer chip 2 which is a first semiconductor chip having a semiconductor element and a plurality of gold bumps (bump electrodes) 1i formed on the main surface 2b, and a second having a semiconductor element and a plurality of electrodes formed on the main surface 3b. A memory chip 3 as a semiconductor chip, and a memory chip 4 as a third semiconductor chip in which a semiconductor element and a plurality of electrodes are formed on the main surface 4b. As an example, the case where the memory chip 3 is Flash Memory and the memory chip 4 is DRAM is taken up, and the microcomputer chip 2 controls the memory chips 3 and 4.

  Thereafter, the main surface 2b of the microcomputer chip 2 and the main surface 1a of the product area 21 of the multi-chip substrate 11 are made to face each other, and the plurality of gold bumps 1i of the microcomputer chip 2 are flipped in the product area 21 of the multi-chip substrate 11 The microcomputer chip 2 is flip-chip connected to the main surface 1a of the product area 21 of the multi-chip substrate 11 by connecting to the chip electrode 1e.

  At that time, the microcomputer chip 2 is flip-chip connected by thermocompression bonding. That is, by heating the flip chip connecting portion, as shown in FIG. 7, the solder precoat 1j on the surface of the flip chip electrode 1e is melted and the microcomputer chip 2 is flip chip connected by gold-solder connection.

  Thereafter, an underfill resin 7 as a first resin is injected between the main surface 2 b of the microcomputer chip 2 and the main surface 1 a of the multi-chip substrate 11 to perform underfill sealing.

  Thereafter, the memory chip 3 is stacked on the microcomputer chip 2 with the back surface 2 c of the microcomputer chip 2 and the back surface 3 c of the memory chip 3 facing each other. At that time, the memory chip 3 is fixed on the microcomputer chip 2 via the die bonding material 9.

  Subsequently, the memory chip 4 is stacked on the microcomputer chip 2 with the back surface 2 c of the microcomputer chip 2 and the back surface 4 c of the memory chip 4 facing each other. At that time, the memory chip 4 is fixed on the microcomputer chip 2 via the die bonding material 9.

  Thereafter, the plurality of pads 3a of the memory chip 3 and the corresponding plurality of bonding pads 1d of the product region 21 of the multi-chip substrate 11 are connected by wires (gold wires) 5 and then the plurality of memory chips 4 are connected. These pads 4 a and the corresponding bonding pads 1 d in the product region 21 of the multi-chip substrate 11 are connected by wires 5.

  Thereafter, the microcomputer chip 2, the memory chip 3, the memory chip 4, and the plurality of wires 5 are sealed with a sealing resin that is a second resin to form a sealing body 6.

  Thereafter, solder balls 8 as external terminals are mounted on the plurality of bump lands 1 c in the product region 21 of the multi-chip substrate 11.

  After mounting the external terminals, the cutting part 20 of the multi-piece substrate 11 is cut by dicing and separated into individual SIPs 10. Thereby, the assembly of the SIP 10 is completed.

  Next, the structure of the flip chip electrode 1e and the bump land 1c of the SIP substrate 1 in the SIP 10 of the present embodiment will be described.

  First, FIG. 9, FIG. 10 and FIG. 11 show the structure of the flip chip electrode 1e of the SIP substrate 1, respectively. The flip chip electrode 1e is surrounded by a solder resist film 1f whose side surface is an insulating film. It is preferable.

  That is, since the side surface of the flip chip electrode 1e is surrounded by the solder resist film 1f, the amount of the solder precoat 1j formed on the connection surface of the flip chip electrode 1e can be reduced. It is possible to avoid a solder short that occurs between the electrodes 1e.

  As a result, the reliability of the chip stack type SIP 10 can be improved, and the yield of the SIP 10 can be improved.

  Further, the pitch of the flip chip electrodes 1e can be reduced.

  As shown in FIG. 10, by increasing the height of the solder resist film 1f surrounding the flip chip electrode 1e, the amount of the solder precoat 1j formed on the connection surface of the flip chip electrode 1e can be surely reduced. As a result, it is possible to more reliably avoid a solder short that occurs between the flip chip electrodes 1e.

  Further, as shown in FIG. 11, the solder resist film 1f has a two-layer structure, and the upper layer solder resist film 1f is arranged at the peripheral edge of the connection surface of the flip chip electrode 1e, thereby forming the connection surface of the flip chip electrode 1e. The amount of solder precoat 1j to be formed can be further reduced, and as a result, solder shorts occurring between the flip chip electrodes 1e can be further avoided.

  Next, FIG. 12, FIG. 13 and FIG. 14 show the structure of the bump land 1c of the SIP substrate 1, and the bump land 1c is a solder whose side surface is an insulating film, like the flip chip electrode 1e. It is preferably surrounded by the resist film 1f.

  Since the side surfaces of the bump lands 1c are surrounded by the solder resist film 1f, the amount of solder balls 8 formed on the connection surfaces of the bump lands 1c can be suppressed. As a result, the solder lands 8 are generated between the adjacent solder balls 8. Solder shorts can be reduced.

  In addition, as shown in FIG. 13, by making the height of the solder resist film 1f higher than the bump land 1c, the amount of solder balls 8 connected to the connection surface of the bump land 1c can be more reliably reduced. As a result, it is possible to more reliably reduce solder shorts that occur between the bump lands 1c.

  Further, as shown in FIG. 14, the solder resist film 1f has a two-layer structure, and the upper solder resist film 1f is arranged on the peripheral portion of the connection surface of the bump land 1c, thereby connecting to the connection surface of the bump land 1c. The amount of solder balls 8 can be further reduced, and as a result, solder shorts occurring between the bump lands 1c can be further reduced.

  Next, a modified example of the SIP substrate 1 incorporated in the SIP 10 of the present embodiment will be described.

  FIG. 15 shows the wiring patterns of the outermost layer (main surface 1a) and the lowermost layer (back surface 1b) of the multi-piece substrate 11 (SIP substrate 1) of the modification. In the modified multi-piece substrate 11 (SIP substrate 1), the electrolytic plating power supply wiring 1h for forming the nickel-gold alloy plating film 1g of the bump land 1c on the back surface 1b is provided on the back surface 1b (lowermost layer). Also formed. That is, as shown in the lowermost layer of FIG. 15, a space (in the center, for example) inside the bump land 1c is used to supply power to the space and the cut portion 20 by using a wide area pattern. Wiring 1h is arranged, and each is connected by lead-like power supply wiring 1h. In this case, a lead-like power supply wiring 1h extends from the bump land 1c arranged on the outer peripheral portion on the back surface 1b toward the common power supply wiring 1h having a large area pattern in the center. Further, the power supply wiring 1h having a large area pattern in the central portion and the plurality of bump lands 1c are connected to each other by lead-shaped power supply wirings 1h. In this way, all the bump lands 1c on the back surface 1b are connected to the common power supply wiring 1h having a large area pattern in the central portion or the cut portion 20 via the lead-shaped power supply wiring 1h.

  In the outermost layer, a plurality of bonding pads 1d (which may be flip chip electrodes 1e) are connected to a common power supply wiring 1h of the cutting portion 20 by a single power supply wiring 1h.

  In a wiring board as shown in FIG. 15, a power supply wiring 1h is used to supply power to each bump land 1c to form a nickel-gold alloy electroplating plating film 1g, and then in the final process of manufacturing the board. Then, in a state where the bonding pad 1d, the bump land 1c and the flip chip electrode 1e are covered with the resist film, the large-area pattern power supply wiring 1h of the cutting portion 20 of the main surface 1a (etching portion 22 indicated by a dotted line in FIG. 15) Then, the central portion of the back surface 1b and the power supply wiring 1h (etched portion 22 indicated by the dotted line) of the wide area pattern of the cut portion 20 are removed by etching as shown in FIG. As a result, the bonding pads 1d on the main surface 1a and the bump lands 1c on the back surface 1b become independent from the power supply wiring 1h having a common large area pattern.

  As described above, the SIP 10 of the present embodiment may be assembled using the SIP substrate 1 manufactured by removing the common power supply wiring 1h by etching after power supply.

  Further, as the SIP substrate 1, a nickel-gold alloy plating film 1g is not formed on the surface of each bump land 1c on the back surface 1b by electroplating, but electroless plating of nickel-gold alloy by electroless plating is performed. You may use what formed the film | membrane.

  When this electroless plating is used, the routing of the wiring pattern on the back surface 1b can be simplified, and the power feeding process for plating can be eliminated, so that the manufacture of the SIP substrate 1 can be simplified. . Further, the cost of the SIP substrate 1 can be reduced.

  Although the invention made by the present inventor has been specifically described based on the embodiments of the invention, the present invention is not limited to the embodiments of the invention, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

  For example, in the above-described embodiment, the case where the SIP 10 includes three semiconductor chips has been described. However, the SIP 10 includes at least two semiconductor chips that are flip-chip connected to the SIP substrate 1 and semiconductor chips that are wire-bonded. As long as it has two semiconductor chips and a plurality of bump lands 1c are formed on the back surface 1b, it may be another SIP 10 or a multi-chip module or a multi-chip package.

  The present invention is suitable for an electronic device, a semiconductor manufacturing technology, and a substrate manufacturing technology.

It is sectional drawing which shows an example of the structure of the semiconductor device of embodiment of this invention. FIG. 2 is a plan view showing the structure of the semiconductor device shown in FIG. 1 through a sealing body. FIG. 2 is a back view showing the structure of the semiconductor device shown in FIG. 1. It is a block block diagram which shows an example of the system of the semiconductor device shown in FIG. FIG. 2 is a cross-sectional view showing an example of the structure of a multi-piece substrate (wiring board) used for assembling the semiconductor device shown in FIG. 1 and a plan view of fifth and sixth layers. FIG. 6 is a manufacturing process flow chart showing an example of a method for forming each electrode of the wiring board shown in FIG. 5. FIG. 2 is a partial enlarged cross-sectional view schematically showing an example of the structure of the semiconductor device shown in FIG. 1. FIG. 6 is a manufacturing process flow chart showing an example of a method for forming a high-precision precoat on the flip chip electrode of the wiring board shown in FIG. 5. FIG. 2 is a partial enlarged cross-sectional view showing an example of a structure of a flip chip electrode in the wiring substrate of the semiconductor device shown in FIG. 1. FIG. 7 is a partial enlarged cross-sectional view illustrating a structure of a flip chip electrode of a modification example of the wiring board of the semiconductor device illustrated in FIG. 1. FIG. 7 is a partial enlarged cross-sectional view illustrating a structure of a flip chip electrode of a modification example of the wiring board of the semiconductor device illustrated in FIG. 1. FIG. 2 is a partial enlarged cross-sectional view illustrating an example of a structure of an external terminal mounting electrode in the wiring board of the semiconductor device illustrated in FIG. 1. FIG. 8 is a partial enlarged cross-sectional view showing a structure of a modified external terminal mounting electrode in the wiring board of the semiconductor device shown in FIG. FIG. 7 is a partial enlarged cross-sectional view showing a structure of a modified external terminal mounting electrode in the wiring board of the semiconductor device shown in FIG. 1. It is a top view which shows the structure of the outermost layer and the lowest layer before the etch back in the removal method of the wiring for electric power feeding of the wiring board of the modification of embodiment of this invention. It is a top view which shows the structure of the outermost layer and the lowest layer after the etch back in the removal method of the wiring for electric power feeding of the wiring board of the modification of embodiment of this invention.

Explanation of symbols

1 SIP board (wiring board)
1a main surface 1b back surface 1c bump land (external terminal mounting electrode)
1d Bonding pad (metal thin wire connection electrode)
1e Flip chip electrode 1f Solder resist film (insulating film)
1g Plating film 1h Power supply wiring 1i Gold bump (Bump electrode)
1j Solder precoat 1k Copper pattern 1m Solder powder 1n Adhesive coating 1p Flux 1q Core part (base substrate)
1r Internal wiring 1s Base via 1t Via 1u Through-hole wiring 1v Resist film (insulating film)
1w Insulating layer 1x Resist film (insulating film)
2 Microcomputer chip (first semiconductor chip)
2a Pad (electrode)
2b main surface 2c back surface 3 memory chip (second semiconductor chip)
3a Pad (electrode)
3b main surface 3c back surface 4 memory chip (third semiconductor chip)
4a Pad (electrode)
4b Main surface 4c Back surface 5 Wire (metal thin wire)
6 Sealing body (second resin)
7 Underfill resin (first resin)
8 Solder balls (external terminals)
9 Die bond material 10 SIP (semiconductor device)
11 Multiple substrate (wiring board)
20 Cutting part 21 Product area 22 Etching part

Claims (10)

A first main surface, a plurality of wirings formed on the first main surface, a plurality of bonding pads formed on the first main surface, a plurality of flip chip electrodes formed on the first main surface, the first A wiring substrate having a first back surface opposite to the main surface and a plurality of external terminal mounting electrodes formed on the first back surface, the wiring substrate including six wiring layers;
A second main surface; a first semiconductor element formed on the second main surface; a plurality of first electrodes formed on the second main surface; and a second back surface opposite to the second main surface. then, the so second main surface opposed to the first main surface of the wiring substrate, a first semiconductor that is flip-chip connected to said first main surface of the wiring substrate via the bump electrode of the multiple Chips,
A third main surface; a second semiconductor element formed on the third main surface; a plurality of second electrodes formed on the third main surface; and a third back surface opposite to the third main surface. A second semiconductor chip disposed on the second back surface of the first semiconductor chip such that the third back surface faces the second back surface of the first semiconductor chip;
A plurality of wires electrically connecting the plurality of second electrodes of the second semiconductor chip and the plurality of bonding pads of the wiring board corresponding to the second electrodes;
A plurality of external terminals mounted respectively on the plurality of external terminal mounting electrodes of the wiring board,
Including
The plurality of bonding pads are formed in a first layer of the plurality of wiring layers,
The plurality of external terminal mounting electrodes are formed in a sixth layer of the plurality of wiring layers,
Each of the plurality of bonding pads is connected to a first power supply wiring for electrolytic plating,
Each of the plurality of external terminal mounting electrodes is connected to a second power supply wiring for electrolytic plating,
A nickel alloy plating film is formed on each surface of the plurality of bonding pads and the plurality of external terminal mounting electrodes,
The first power supply wiring is formed in a first layer of the plurality of wiring layers,
The second power supply wiring is formed in each of a fifth layer and a sixth layer of the plurality of wiring layers .   2. The semiconductor device according to claim 1, wherein the plating film is a nickel-gold alloy film.   2. The semiconductor device according to claim 1, wherein each of the plurality of flip chip electrodes of the wiring board is surrounded by an insulating film.   2. The semiconductor device according to claim 1, wherein each of the plurality of external terminals comprises a solder ball.   2. The semiconductor device according to claim 1, wherein each of the plurality of bump electrodes is a gold bump electrode.   2. The semiconductor device according to claim 1, wherein each of the plurality of wires is a gold wire.   The semiconductor device according to claim 1, wherein a third semiconductor chip is mounted on the second back surface of the first semiconductor chip, and a plurality of third electrodes formed on a fourth main surface of the third semiconductor chip. And a plurality of bonding pads of the wiring board corresponding thereto are electrically connected by a plurality of wires, respectively.   2. The semiconductor device according to claim 1, wherein the plurality of bonding pads are arranged outside the plurality of flip chip electrodes. 9. The semiconductor device according to claim 8 , wherein the plating film is not formed on the plurality of flip chip electrodes of the wiring board. 10. The semiconductor device according to claim 9 , wherein the first and second power supply wirings are not connected to the plurality of flip chip electrodes on the main surface of the wiring board.

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