JPS5889859A - Fabrication method of micro cantilever on silicon wafer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention forms micro-cantilevers and beams of silicon wafer on silicon wafer/S, which have gold-containing wires that deflect and switch light beams. I am passionate about the stone method.

The conventional method for making a four-cantilever microphone beam is explained in the 1st ACL.
The connection is shown in Figure 4. In each figure, (A) is horizontal direction -1 (
B) is the cut thl- at 1 minute in the part indicated by the dotted line in (A).
It is.

To explain the conventional method with reference to this diagram, first, a high-concentration plowing operation is applied to the surface of the silicon wafer 1, and then the surface is heated.
After forming the P+ layer 2, a single crystal silicon layer 3. is epitaxially grown and further oxidized and treated to form an acidic silicon oxide layer 4 on the surface of the silicon Fm30. t
- form. Next, a gold #I thin film 5, which also serves as an electrode and a layer, is formed on at least the micro-cantilever.

Then, the silicon oxide layer 4t- around this metal thin film 5
It is removed in a concave manner to form an opening 6Yr.

(Refer to the first melting point) Thereafter, chemical etching of the silicone layer 3 is performed using this opening 6. Proceed to the vagueness of this Nitsutenda ore in Figures 2, 3, and 4. That is, first, the portion of the silicon layer 3 exposed by the opening 6 is etched in a V shape, and at the same time, as the V shape gradually becomes deeper, the silicon layer 3 under the silicon oxide #4 in the portion that will become a micro cantilever is etched. Etching progresses to rfiI3. Therefore, when this etching is completed, the silicon oxide layer 4 (having a metal thin layer @5t- on the upper surface) in the area surrounded by the front mouth part 6 has a thickness of 14 mm.
29 cantilever beam 7. Note that the depth of the chemical eratin is greater than that described above.

By applying an electrostatic field between the micro cantilever 7 formed in the above manner, the gold III* film 5 deposited on its upper surface, and the silicon wafer 1, the beam is deflected. Since the amount of tightening can be controlled by voltage, it can be applied to electrical components in deflection elements, etc.

However, the conventional manufacturing normal as described above has a large difference as described below. First, in order to provide P"Jii2, it is necessary to dope extremely high -11111kK impurities, and a dedicated diffusion furnace is required for this purpose.
lOμw & 8 on top! 3 tons of silicon layer with a thickness of more than
- Extremely advanced technology of epitaxial growth
Second, it takes a long time to complete the etching of the single crystal silicon layer 3 shown in FIGS. 2 to 4, and the etching rate varies greatly depending on the crystal orientation. , the orientation line of the i-micro cantilever 7 formed on the silicon wafer 11 is limited to a specific crystal plane direction and has no degree of freedom. Since the surface 8, that is, the top surface of the exposed 21 layer 2, is not a mirror surface but a diffuse reflection surface, when used as an optical element, either the diffuse reflection light from the bottom surface 8 or the specular reflection from the top surface of the micro cantilever holder 7 is generated. The disadvantage is that it mixes into the luminous flux.

In view of the above points, this invention is a good one and can solve the above-mentioned disadvantages.
The purpose of this paper is to provide a method for manufacturing a 9-cantilever beam. ~ Hereinafter, the present invention will be explained with reference to the 11kI pH aspect. Figures 5 to II8 are diagrams showing an example of the actual invention '1#A'. In Figure 6, (A) is a plan view, (B)
is a cross-sectional view at a portion indicated by a point - in (A).

To explain the process using this figure, first, a silicon wafer 11 that has been polished on one side is oxidized, and a silicon oxide layer (109 silicon Ml) 12t- generate.

Next, the silicate oxide s y @ 12 (D'lRm
&C1 After approximately 20,411 layers of polycrystalline silicon layer 13 are formed by the CVD method, the lI! Polish one side of the screw,
The polycrystalline silicon layer 13 is a polycrystalline silicon layer having a thickness of about lOμII@[0. After that, Denbi Oxidation IIJ1!1
By doing this, a silicon oxide layer ($I2 silicon oxide j
li) Generate 14. After that, at least Mike-
Metal thin layer 1 is placed on the European silicon layer 14 of the part that will become the cantilever.
115t' is formed. Then, the oxidized silicone around the thin metal 1 [15 is removed in a concave manner to form the mouth portion 16.
form. (See No. 5-) Thereafter, chemical etching of the polycrystalline silicon layer 13ID is performed using this opening 16. This etching Hiro 1t
Proceed to figures la, figures 7 and 8.

That is, first, the portion of the polycrystalline silicon layer 13 that is not exposed by the opening 16 is etched shallowly, and then the etching process gradually slows down and at the same time, the portion that will become the micro cantilever is oxidized. Etching progresses to the polycrystalline silicon layer 1.3 below the silicone layer 14. Therefore, when this etching is completed, the oxidized silicone layer 14 (included in the metal thin layer 1115 on the upper surface) in the portion surrounded by the front 1e and bottom portions 16 is removed.
becomes the i-level cantilever beam 17.・Note that the chemical etching is blocked by silicon oxide 112.
The depth of the space under the cantilevered lock 17 is equal to the thickness of the polycrystalline silicon layer 13.

As is clear from the above description, in the method of the present invention, a silicon oxide layer is used in place of the conventional P layer.
In addition, instead of the silane layer, a polycrystalline silicon layer produced by CVD or the like is used.

Therefore, according to the manufacturing method of the present invention, first, there is no work to remove impurity pitch 'Ill [Kdawg] during the tabulation process, so there is an advantage that the normal process for manufacturing conductor elements can be applied. Next, on the surface of the silicon wafer, which has become rough due to the excessive doping of impurities, single-crystal silicon 1li1 with a size of 10μ1 or more can be grown using CVD or other methods without requiring sophisticated technology. The advantage is that a simple method can be used to produce crystalline silicon. Nine, in the four-microphone cantilever made using the conventional method, the bottom surface of the lower part of the microphone cantilever does not become the key part, whereas in the four-microphone cantilever made using this method, the polycrystalline silicon layer The silicon oxide layer in a polished state (by polishing the silicon wafer, the surface of the silicon oxide layer naturally becomes mirror-finished) before it is produced. Therefore, when using this four cantilever beam as an optical element such as a light deflection element, the bottom E[
18 (shown in No. 8) is extremely small.
There is an advantage. Also, this manufacturing method involves chemically etching the polycrystalline silicon layer! Since a cantilever beam is formed, the direction of the four-microphone cantilever beam is not limited to a specific direction, and there is an advantage that the time required for etching is very small. In the conventional production method, a layer of monocrystalline silicon is formed on the shrimp taxi, and then the reIulm process is repeated on top of the micro cantilever vermilion. Although it is impossible to create micro-cantilever beams with a layered structure, this method can be applied to polycrystalline silicon.
Since it generates , it has the advantage that a multi-organ structure is possible.

[Brief explanation of the drawing]

Giri! Figures J to 4 show enlarged conventional micro cantilever manufacturing methods, respectively (A) a plan view and C respectively.
B) is a cross-sectional view, and the enlargement of Figures 5 to 8 is almost clear! The method for making cantilever beams is shown below, and (4) is flat.
r, respectively CB) a cross section -. DESCRIPTION OF SYMBOLS 11... Silicon wafer, 12... Silicon oxide layer, 13... Polycrystalline silicon layer, 14... Silicon oxide layer, 15... Gold maple thin film, 16... - Mouth part, 17
...Mikle cantilevered sash. Spear 1 Picture Spear 4 Flash Spear 511 Spear Sag Procedural Amendment May 28, 1980 Patent Office Commissioner Island 1) Spring Tree 1, Incident Indication 1937 Patent Application No. 11NIIIIT No. 2
, 尭＠O Name - Siri;P Microphone cylinder cantilever mounted on the top of the amp; Person 5, date of amendment order Showa year month day (self I
I) Figure 3

Claims (1)

[Claims] Ichimenken WI! After forming a first silicon oxide layer on the silicon wafer/S and forming polycrystalline silicon on the first silicon wafer/S,
A second silicon oxide layer is formed on the -surface polished m surface of the J surface, and furthermore, at least a micro cantilever,
A process of forming a metal thin film on the second silicon oxide layer in the area where the area is slightly damaged, and a polycrystalline silicon layer formed by finely decaching the second silicon oxide layer around the entire island*a. and a step of removing the polycrystalline silicon layer under the #I2 silicon oxide layer in the portion that will become the micro cantilever.