CN102800599B - Bump process and its structure - Google Patents

Abstract

The invention relates to a bump process, which comprises a substrate; forming a copper-containing metal layer; forming a photoresist layer; patterning the photoresist layer to form a plurality of openings; forming a plurality of copper bumps in the openings, wherein each copper bump has a first top surface; forming a bonding layer comprising a nickel layer and a bonding layer, wherein the bonding layer has a second top surface; removing the photoresist layer; forming a bump lower metal layer, wherein each bump lower metal layer is provided with a first peripheral wall, each copper bump is provided with a second peripheral wall, an accommodating space is arranged between the conductive connection layer and the first protective layer of the substrate, the accommodating space surrounds the first peripheral wall and the second peripheral wall, and the accommodating space is provided with a first accommodating part and a pair of second accommodating parts; forming a second protective layer; and removing part of the second protective layer to form a first protective ring on the second protective layer positioned in the first accommodating part and a second protective ring on the second protective layer positioned in the second accommodating part.

Description

Bump process and its structure

technical field

The present invention relates to a bump technology, in particular to a bump technology capable of preventing short circuit.

Background technique

As shown in FIGS. 1A to 1H , the conventional bumping process includes at least the following steps: First, referring to FIG. 1A , a substrate 10 is provided, and the substrate 10 has a surface 11 and a plurality of soldering pads 12 disposed on the surface 11. And a protection layer 13 formed on the surface 11, the protection layer 13 exposes the pads 12; then, referring to FIG. 1B, a copper-containing metal layer 20, the pads 12 and the protection layer 13 are formed; , see FIG. 1C, form a photoresist layer 30 on the copper-containing metal layer 20; then, see FIG. 1D, pattern the photoresist layer 30 to form a plurality of openings 31; then, see FIG. 1E, form multiple A copper bump 40 is in these openings 31, and each of these copper bumps 40 has a first peripheral wall 41; Then, referring to FIG. 1F, a conductive layer 50 and these copper bumps 40 are formed; Referring to FIG. 1G, the photoresist layer 30 is removed. Finally, referring to FIG. 1H, the copper-containing metal layer 20 not covered by the copper bumps 40 is removed by etching to form an UBM layer 21. , each of the UBM layers 21 has a second peripheral wall 21a, when the step of removing the copper-containing metal layer 20 not covered by the copper bumps 40 is performed, due to the material of the copper bumps 40 contains copper, so the copper bumps 40 will be etched together with the copper-containing metal layer 20 to cause the first peripheral walls 41 of the copper bumps 40 to be recessed, and the bumps The second peripheral walls 21a of the lower metal layer 21 are more recessed than the first peripheral walls 41 of the copper bumps 40. In addition, because the first peripheral walls 41 and the second peripheral walls 21a It is recessed and exposed, so it is easy to cause copper ions to dissociate and cause a short circuit.

It can be seen that the above-mentioned existing bump technology obviously still has inconvenience and defects in structure and use, and needs to be further improved urgently. Therefore, how to create a new type of structural bump technology and its structure has also become a goal that needs to be improved in the current industry.

Contents of the invention

The purpose of the present invention is to overcome the defects of the existing bump technology, and provide a new structure of the bump technology and its structure, the technical problem to be solved is to make it avoid the metal layer under the bump The situation that the first peripheral walls and the second peripheral walls of the copper bumps are exposed to cause copper ions to dissociate and cause a short circuit is very suitable for practical use.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. A bumping process proposed according to the present invention at least includes: providing a substrate, the substrate has a surface, a plurality of pads and a first protection layer, the pads are arranged on the surface, the first protection layer Formed on the surface and exposing the pads; forming a copper-containing metal layer on the pads and the first protective layer, the copper-containing metal layer has a plurality of first regions and a plurality of second regions; forming a photo resist layer on the copper-containing metal layer; pattern the photoresist layer to form a plurality of openings, the openings correspond to the first regions; form a plurality of copper bumps in the openings, each of the copper bumps covers the Each of the first areas of the copper-containing metal layer and each of the copper bumps have a first top surface; a conductive layer is formed on the first top surfaces of the copper bumps, and the conductive layer has a second The top surface and the conductive layer include a nickel layer and a bonding layer, the nickel layer is located between the copper bump and the bonding layer; the photoresist layer is removed; the second layers of the copper-containing metal layer are removed region to expose the first protection layer, and make each of the first regions of the copper-containing metal layer form an under bump metallurgy layer, wherein each of the under bump metallurgy layers has a first peripheral wall, and each of the copper bumps The block has a second peripheral wall, the conductive layer has a third peripheral wall, there is a first distance between the third peripheral wall and the second peripheral wall, and the distance between the third peripheral wall and the first peripheral wall There is a second distance between the conductive layer and the first protective layer, and there is an accommodating space surrounding the first peripheral wall and the second peripheral wall, and the accommodating space has a corresponding A first accommodating portion of the first peripheral wall and a second accommodating portion corresponding to the second peripheral wall; a second protective layer is formed on the second top surface of the conductive layer, the bumps The first peripheral walls of the lower metal layer, the second peripheral walls of the copper bumps, the third peripheral wall of the conductive layer, the first protection layer, the first accommodating portion and the second two accommodation parts; and remove the second top surface of the conduction layer, the third peripheral wall of the conduction layer and the second protection layer of the first protection layer, so that the second protection layer located in the first accommodation The second protection layer at the placement part forms a first protection ring and the second protection layer at the second accommodation part forms a second protection ring.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

The aforementioned bump process, wherein the third outer peripheral wall has a third outer peripheral length, the second outer peripheral wall has a second outer peripheral length, the first outer peripheral wall has a first outer peripheral length, and the third outer peripheral wall longer than the second outer perimeter, and the second outer perimeter is not smaller than the first outer perimeter.

In the aforementioned bump process, the second pitch is not smaller than the first pitch.

In the aforementioned bump process, the second protective layer is selected from one of oxide and nitride.

In the aforementioned bump process, the nitride may be one of silicon nitride, silicon oxynitride or a mixture thereof.

In the aforementioned bump process, the oxide may be one of silicon dioxide, silicon oxynitride or a mixture thereof.

The aforementioned bump process, wherein the first guard ring has a first ring wall, the second guard ring has a second ring wall, the first ring wall, the second ring wall and the third outer circumference The walls are flush.

The purpose of the present invention and the solution to its technical problem also adopt the following technical solutions to achieve. A bump structure proposed according to the present invention at least includes: a substrate having a surface, a plurality of solder pads and a first protective layer, the solder pads are arranged on the surface, and the first protective layer is formed on The surface exposes the pads; a plurality of UBM layers, each of which has a first peripheral wall; a plurality of copper bumps formed on the UBM layers, each of which has a first peripheral wall The copper bump has a first top surface and a second peripheral wall; a conductive layer is formed on the first top surfaces of the copper bumps, and the conductive layer has a second top surface and a The third peripheral wall, and the conductive layer includes a nickel layer and a bonding layer, the nickel layer is located between the copper bump and the bonding layer, wherein there is a gap between the third peripheral wall and the second peripheral wall The first distance, there is a second distance between the third peripheral wall and the first peripheral wall, and there is an accommodating space between the conductive layer and the first protective layer, and the accommodating space surrounds the first peripheral wall wall and the second outer peripheral wall, and the accommodating space has a first accommodating portion corresponding to the first outer peripheral wall and a second accommodating portion corresponding to the second outer peripheral wall; a first protective ring, It is formed in the first accommodating portion; and a second protection ring is formed in the second accommodating portion.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

In the aforementioned bump structure, the first guard ring is connected to the second guard ring.

The aforementioned bump structure, wherein the first protection ring has a first ring wall, the second protection ring has a second ring wall, the first ring wall, the second ring wall and the third outer circumference The walls are flush.

Compared with the prior art, the present invention has obvious advantages and beneficial effects. It can be seen from the above technical solutions that the main technical content of the present invention is as follows: to provide a bumping process, which includes providing a substrate with a surface, a plurality of solder pads and a first protection layer, and the solder pads are set On the surface, the first protection layer is formed on the surface and exposes the pads; a copper-containing metal layer is formed on the pads and the first protection layer, and the copper-containing metal layer has a plurality of first regions and A plurality of second regions; forming a photoresist layer on the copper-containing metal layer; patterning the photoresist layer to form a plurality of openings, the openings corresponding to the first regions; forming a plurality of copper bumps in the openings Inside, each of the copper bumps covers each of the first regions of the copper-containing metal layer and each of the copper bumps has a first top surface; a conductive layer is formed on the first top surfaces of the copper bumps , the conductive layer has a second top surface and the conductive layer includes a nickel layer and a bonding layer, the nickel layer is located between the copper bump and the bonding layer; removing the photoresist layer; removing the The second regions of the copper-containing metal layer expose the first protection layer, and each of the first regions of the copper-containing metal layer forms an UBM layer, wherein each of the UBM layers has an The first peripheral wall, each of the copper bumps has a second peripheral wall, the conductive layer has a third peripheral wall, there is a first distance between the third peripheral wall and the second peripheral wall, and the third peripheral wall has a first distance from the second peripheral wall. There is a second distance between the outer peripheral wall and the first outer peripheral wall, and there is an accommodating space between the conductive layer and the first protective layer, and the accommodating space surrounds the first outer peripheral wall and the second outer peripheral wall , and the accommodating space has a first accommodating portion corresponding to the first peripheral wall and a second accommodating portion corresponding to the second peripheral wall; a second protective layer is formed on the conductive layer the second top surface, the first peripheral walls of the UBM layers, the second peripheral walls of the copper bumps, the third peripheral wall of the conductive layer, the first protection layer, the first accommodating portion and the second accommodating portion; and removing the second protection located on the second top surface of the conducting layer, the third peripheral wall of the conducting layer and the first protection layer layers, so that the second protection layer located in the first accommodation part forms a first protection ring and the second protection layer located in the second accommodation part forms a second protection ring.

With the above-mentioned technical solution, the bumping process and its structure of the present invention have at least the following advantages and beneficial effects: Since the first protection rings are formed around the first receiving portions of the UBM layers, the surrounding The second receiving portions of the copper bumps are formed with the second guard rings, so that the first peripheral walls of the UBM layers and the second peripheral walls of the copper bumps can be avoided. The wall is exposed to cause copper ions to dissociate and cause a short circuit.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

1A to 1H are schematic cross-sectional views of a conventional bumping process.

2A to 2J are schematic cross-sectional views of a bump process according to a preferred embodiment of the present invention.

10: Substrate 11: Surface

12: Welding pad 13: Protective layer

20: copper-containing metal layer 21: under-bump metal layer

21a: Second peripheral wall

30: photoresist layer 31: opening

40: copper bump 41: first peripheral wall

50: Conductive layer

100: bump structure

110: Substrate 111: Surface

112: Welding pad 113: The first protective layer

120: copper-containing metal layer 121: first zone

122: Second area 123: UBM layer

123a: first peripheral wall

130: photoresist layer 131: opening

140: copper bump 141: first top surface

142: second peripheral wall

150: Conducting layer 151: Second top surface

152: Nickel layer 153: Bonding layer

154: third peripheral wall

160: Second protective layer 161: First protective ring

161a: first ring wall 162: second protective ring

162a: Second ring wall

D1: first distance D2: second distance

L1: first outer perimeter L2: second outer perimeter

L3: third outer perimeter

S: storage space S1: first storage part

S2: The second storage part

Detailed ways

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, the specific implementation, structure, characteristics and structure of the bump technology and its structure proposed according to the present invention will be described below in conjunction with the accompanying drawings and preferred embodiments. Its effect is described in detail below.

Please refer to FIG. 2A to FIG. 2J, a preferred embodiment of the present invention, a bumping process, which at least includes the following steps: first, please refer to FIG. 2A, providing a substrate 110, the substrate 110 has a surface 111, A plurality of welding pads 112 and a first protective layer 113, these welding pads 112 are arranged on the surface 111, the first protective layer 113 is formed on the surface 111 and exposes these welding pads 112, the material of the substrate 110 is optional From one of silicon germanium substrate, gallium arsenide substrate or sapphire substrate, the material of the first protective layer 113 can be selected from one of silicon dioxide, silicon nitride, silicon oxynitride or a mixture thereof; then , please refer to FIG. 2B, forming a copper-containing metal layer 120 on the pads 112 and the first protective layer 113, the copper-containing metal layer 120 has a plurality of first regions 121 and a plurality of second regions 122; after that, Referring to FIG. 2C, a photoresist layer 130 is formed on the copper-containing metal layer 120; then, please refer to FIG. 2D, the photoresist layer 130 is patterned to form a plurality of openings 131, and these openings 131 correspond to the first regions 121; after that, referring to FIG. 2E, a plurality of copper bumps 140 are formed in the openings 131, each of the copper bumps 140 covers each of the first regions 121 of the copper-containing metal layer 120 and each of the copper bumps 140 has a first top surface 141; then, referring to FIG. 2F, a conductive layer 150 is formed on the first top surfaces 141 of the copper bumps 140, the conductive layer 150 has a second top surface 151 and The conductive layer 150 includes a nickel layer 152 and a bonding layer 153. The nickel layer 152 is located between the copper bump 140 and the bonding layer 153. The material of the bonding layer 153 can be selected from gold, silver or lead. One, in this embodiment, the bonding layer 153 is made of gold; then, please refer to FIG. 2G, remove the photoresist layer 130; then, please refer to FIG. 2H, remove the copper-containing metal layer 120 These second regions 122 are used to expose the first protection layer 113, and each of the first regions 121 of the copper-containing metal layer 120 forms an UBM layer 123, wherein each of the UBM layers 123 has a The first peripheral wall 123a, each copper bump 140 has a second peripheral wall 142, the conductive layer 150 has a third peripheral wall 154, the first peripheral wall 123a has a first peripheral length L1, the second The outer peripheral wall 142 has a second outer peripheral length L2, the third outer peripheral wall 154 has a third outer peripheral length L3, the third outer peripheral length L3 is larger than the second outer peripheral length L2, and the second outer peripheral length L2 is not smaller than the first outer peripheral length L2. There is a first distance D1 between the third peripheral wall 154 and the second peripheral wall 142, and a second distance D2 between the third peripheral wall 154 and the first peripheral wall 123a. The second distance D2 is not smaller than the first distance D1, and there is an accommodating space S between the conductive layer 150 and the first protective layer 113, and the accommodating space S surrounds the first peripheral wall 123a and the second peripheral wall 142, and the accommodating space S has a A first housing portion S1 corresponding to the first peripheral wall 123a and a second housing portion S2 corresponding to the second peripheral wall 142; then, referring to FIG. 2I, a second protective layer 160 is formed on the guide The second top surface 151 of the bonding layer 150, the first peripheral walls 123a of the UBM layers 123, the second peripheral walls 142 of the copper bumps 140, the conductive layer 150 The third peripheral wall 154, the first protection layer 113, the first accommodation portion S1 and the second accommodation portion S2, the second protection layer 160 can be selected from one of oxides or nitrides, in this paper In an embodiment, the nitride can be silicon nitride, and the oxide can be silicon dioxide; finally, please refer to FIG. The third outer peripheral wall 154 and the second protective layer 160 of the first protective layer 113, so that the second protective layer 160 located in the first accommodating portion S1 forms a first protective ring 161, and the The second protection layer 160 of the second accommodating portion S2 forms a second protection ring 162 to form a bump structure 100 , and the first protection ring 161 is connected to the second protection ring 162 . Since the first guard rings 161 are formed around the first receiving portions S1 of the UBM layers 123 , the first guard rings 161 are formed around the second receiving portions S2 of the copper bumps 140 . Two guard rings 162, so the first peripheral walls 123a of the UBM layers 123 and the second peripheral walls 142 of the copper bumps 140 are not exposed, so that short circuits caused by copper ion dissociation can be avoided situation.

Preferably, in this embodiment, the first protection ring 161 has a first ring wall 161a, the second protection ring 162 has a second ring wall 162a, the first ring wall 161a, the second ring wall 162a and the third peripheral wall 154 are flush.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify them into equivalent embodiments with equivalent changes, but as long as they do not depart from the technical solution of the present invention, the Technical Essence Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (7)

1. A bump process, characterized in that it comprises at least: A substrate is provided, the substrate has a surface, a plurality of pads and a first protection layer, the pads are disposed on the surface, the first protection layer is formed on the surface and exposes the pads; forming a copper-containing metal layer on the pads and the first protective layer, the copper-containing metal layer has a plurality of first regions and a plurality of second regions; forming a photoresist layer on the copper-containing metal layer; patterning the photoresist layer to form a plurality of openings, the openings corresponding to the first regions; forming a plurality of copper bumps in the openings, each of the copper bumps covering each of the first regions of the copper-containing metal layer and each of the copper bumps having a first top surface; forming a conductive layer on the first top surfaces of the copper bumps, the conductive layer has a second top surface and the conductive layer includes a nickel layer and a bonding layer, the nickel layer is located on the copper bumps between the block and the bonding layer; removing the photoresist layer; removing the second regions of the copper-containing metal layer to reveal the first protective layer, and forming an UBM layer in each of the first regions of the copper-containing metal layer, wherein each of the UBM The layer has a first peripheral wall, each of the copper bumps has a second peripheral wall, the conductive layer has a third peripheral wall, and there is a first distance between the third peripheral wall and the second peripheral wall, There is a second distance between the third peripheral wall and the first peripheral wall, and there is an accommodating space between the conductive layer and the first protective layer, and the accommodating space surrounds the first peripheral wall and the first peripheral wall Two outer peripheral walls, and the accommodating space has a first accommodating portion corresponding to the first outer peripheral wall and a second accommodating portion corresponding to the second outer peripheral wall; forming a second protective layer on the second top surface of the conductive layer, the first peripheral walls of the UBM layers, the second peripheral walls of the copper bumps, the conductive layer The third peripheral wall, the first protective layer, the first housing portion and the second housing portion, the second protective layer covers the second peripheral walls to avoid copper ions from the copper bumps Free, the second protective layer is selected from one of silicon dioxide, silicon oxynitride or a mixture thereof, silicon nitride, silicon oxynitride or a mixture thereof; and removing the second top surface of the conducting layer, the third peripheral wall of the conducting layer and the second protection layer of the first protection layer, so that the second protection layer located in the first accommodating portion The protection layer forms a first protection ring and makes the second protection layer at the second accommodating part form a second protection ring. 2. The bumping process according to claim 1, wherein the third peripheral wall has a third peripheral length, the second peripheral wall has a second peripheral length, and the first peripheral wall has a first peripheral length long, the third outer perimeter is longer than the second outer perimeter, and the second outer perimeter is not smaller than the first outer perimeter. 3. The bumping process as claimed in claim 1, wherein the second pitch is not smaller than the first pitch. 4. The bump process according to claim 1, wherein the first guard ring has a first ring wall, the second guard ring has a second ring wall, the first ring wall, the second ring The wall and the third peripheral wall are flush. 5. A bump structure, characterized in that it comprises at least: A substrate having a surface, a plurality of welding pads and a first protective layer, the welding pads are arranged on the surface, the first protective layer is formed on the surface and exposes the welding pads; a plurality of UBM layers, each of which has a first peripheral wall; a plurality of copper bumps formed on the UBM layers, each of the copper bumps has a first top surface and a second peripheral wall; A conductive layer formed on the first top surfaces of the copper bumps, the conductive layer has a second top surface and a third peripheral wall, and the conductive layer includes a nickel layer and a bonding layer, the nickel layer is located between the copper bump and the bonding layer, wherein there is a first distance between the third peripheral wall and the second peripheral wall, and between the third peripheral wall and the first peripheral wall There is a second distance between the conductive layer and the first protection layer, and there is an accommodating space, the accommodating space surrounds the first peripheral wall and the second peripheral wall, and the accommodating space has a corresponding to a first accommodating portion of the first peripheral wall and a second accommodating portion corresponding to the second peripheral wall; A first protection ring, which is formed in the first accommodating portion, the first protection ring prevents the copper ions from dissociation of the copper bumps, and the first protection ring is selected from silicon dioxide, silicon oxynitride or a mixture thereof one of silicon nitride, silicon oxynitride, or a mixture thereof; and A second protection ring, which is formed in the second accommodating portion, the second protection ring prevents the dissociation of copper ions of the copper bumps, and the second protection ring is selected from silicon dioxide, silicon oxynitride or a mixture thereof one of silicon nitride, silicon oxynitride, or a mixture thereof. 6. The bump structure as claimed in claim 5, wherein the first guard ring is connected to the second guard ring. 7. The bump structure according to claim 5, wherein the first protective ring has a first ring wall, the second protective ring has a second ring wall, the first ring wall, the second ring The wall and the third peripheral wall are flush.