JPH0794464A - Methods for protecting and etching circuit pattern formed on silicon wafer - Google Patents

Abstract

PURPOSE:To protect a circuit pattern from an aqueous solution of potassium hydroxide contained in an etchant by applying a photoresist containing rubber and bisazide to the circuit pattern forming surface of a silicon wafer on which the circuit pattern is formed and baking the photoresist. CONSTITUTION:A photoresist 7 containing rubber and bisazide is applied to the circuit pattern forming surface of a silicon wafer 1 on which a thermal head pattern for ink jet printer is formed from a supplying section 6 and photoresist 7 is spin-coated by using a spin coater table 8. After spin-coating the photoresist 7, the wafer 1 is taken out from the table 8 and set in an electric furnace so as to harden the photoresist 7 by baking. Then the wafer 1 is dipped in an aqueous solution of potassium hydroxide. Therefore, the thermal head pattern for ink jet printer on the surface of the wafer 1 is protected even when the silicon of the wafer 1 is etched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for protecting a circuit pattern formed on a silicon wafer from an aqueous solution of potassium hydroxide which is an etching solution for silicon. The present invention relates to a method for protecting a circuit pattern of the above from an etching solution and an etching method.

[0002]

2. Description of the Related Art Conventionally, in order to protect a circuit pattern formed on a silicon wafer from an aqueous solution of potassium hydroxide which is an etching solution for silicon, a jig as shown in FIG. 12 has been used. The wafer 61 is placed with the circuit pattern side of the wafer 61 facing the holder 62, and the O-rings 63, 6
The holders 65 are stacked with the wafers 4 interposed therebetween, and the wafer 61 is fixed between the holders 62 and 65 with screws (not shown). By putting this in a potassium hydroxide aqueous solution, the circuit pattern surface side of the wafer 61 is protected without coming into contact with the potassium hydroxide aqueous solution. The side of the wafer 61 on which the circuit pattern is not formed can be etched by coming into contact with a potassium hydroxide aqueous solution through the opening 66. It goes without saying that it is necessary to pattern the silicon nitride film in accordance with the shape to be etched in advance to expose silicon on the side in contact with the aqueous potassium hydroxide solution.

[0003]

Since the conventional method for protecting the circuit pattern formed on the silicon wafer as described above uses a jig, it occupies a large volume and the number of wafers that can be processed in one batch is small. It has a drawback that productivity is poor because the number is small and automation is difficult.

[0004]

A method of protecting a circuit pattern formed on a silicon wafer according to the present invention is a method in which a rubber + bisazito type photoresist is applied to a silicon wafer having a circuit pattern formed thereon and baked to solidify. ,
The circuit pattern formed on the silicon wafer is protected from an aqueous solution of potassium hydroxide which is an etching solution for silicon. Moreover, the circuit pattern formed on the silicon wafer is protected by using a rubber + bisazito type photoresist having a viscosity of 100 cp or more. Further, the circuit pattern formed on the silicon wafer is protected by applying and baking a rubber + bisazito type photoresist a plurality of times. In addition, the circuit pattern formed on the silicon wafer is protected by applying an aminosilane-based adhesion promoter and then applying a rubber + bisazito-based photoresist and baking to solidify. In addition, a circuit pattern formed on a silicon wafer by applying a mixture of an aminosilane-based adhesion promoter and an alcohol-based solvent containing water, and then applying and baking a rubber + bisazito-based photoresist to solidify the same. Protect. In the etching method according to the present invention, the circuit pattern is protected by the above-mentioned method and then immersed in an aqueous potassium hydroxide solution.

[0005]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a process diagram showing a first embodiment of an etching method using a protection method according to the present invention, and FIG.
FIG. 3 is a plan view showing a silicon wafer etched by the etching method shown in FIG. 3, FIGS. 3 to 6 are views for explaining the etching method shown in FIG. 1, and FIG. 7 is a plan view showing the silicon wafer after etching.

As shown in FIG. 2 (a), a plurality of identical thermal head patterns 1a are formed on the front surface side of the 4-inch silicon wafer 1 to be etched, and on the back surface side where no thermal head pattern is formed. As shown in FIG. 2B, the silicon nitride (silicon nitride film) 2 is uniformly applied, and a silicon exposed portion 3 where the silicon nitride 2 is not applied is partially formed. The region where the silicon nitride 2 is formed is not etched. 2 (c) is shown in FIG.
2A is an enlarged view of the A portion, and the silicon exposed portion 3 of FIG. 2B is located just on the back surface side of the slot position 5 shown in FIG. 2C. A heating portion 4 is formed on each thermal head pattern 1a, and a slot position 5 is arranged at a position where there is no wiring pattern. In this embodiment, the slot position 5 (silicon exposed portion 3) is formed by the etching process shown in FIG.
A slot is opened in the slot. This slot is used as an ink reservoir when the thermal head pattern portion is incorporated in the print head.

In FIG. 1, of the etching steps of steps 20 to 24, steps 20 to 23 are steps of protecting the circuit (thermal head) pattern formed on the silicon wafer 1.

As shown in FIG. 3, on the circuit pattern surface (front surface) side of the silicon wafer 1 on which the thermal head pattern for the ink jet printer is formed, a rubber + bisazito type photoresist (for example, Tokyo Ohka (manufactured by)) OM
R-83) is dropped from the supply unit 6 (step 21), and spin coating is performed at 300 rpm for 30 seconds using the spin coater table 8 (step 22). By spin coating, the film thickness of the photoresist is made uniform as shown in FIG. Next, the silicon wafer on which the photoresist has been spin-coated is taken out from the spin coater table 8, placed in the electric furnace 8 as shown in FIG. 5, and the wafer is baked at 150 ° C. for 30 minutes to solidify the photoresist (step 23). ). This wafer is immersed in a 20% potassium hydroxide aqueous solution (85 ° C.) for 4 hours in the container shown in FIG. 6 (step 24) to etch silicon, and the ink supply slot 13 is opened as shown in FIG. .

As a result, the thermal head pattern for the ink jet printer on the wafer surface was protected even after the etching.

FIG. 8 shows a second etching method according to the present invention.
FIG. 6 is a process drawing showing an example of FIG. Similar to the above-described embodiment, on the circuit pattern surface side of the wafer 1 (FIG. 1) on which the thermal head pattern for the ink jet printer is formed,
OMR-83 (Tokyo Ohka Kogyo Co., Ltd.) is supplied as a rubber + bisazito photoresist and spin-coated at 300 rpm for 30 seconds (steps 31 and 32). 15 wafers
Baking is performed at 0 ° C. for 30 minutes to apply and solidify the photoresist three times in total (step 34). Next, this wafer is 20%
Immerse in an aqueous solution of potassium hydroxide (85 ° C.) for 4 hours (step 35), etch silicon, and open ink supply slot 13 (FIG. 7).

As a result, the thermal head pattern for the ink jet printer on the wafer surface was protected even after the etching. Further, by applying and solidifying the photoresist three times, pinholes in the photoresist were eliminated and reliability was improved.

FIG. 9 shows a third etching method according to the present invention.
FIG. 6 is a process drawing showing an example of FIG.

On the circuit pattern surface side of the wafer 1 (FIG. 1) on which the thermal head pattern for the ink jet printer is formed, a rubber + bisazito type photoresist OMR-made by Tokyo Ohka Co., Ltd. having a viscosity of 100 cp-- 83
And spin coating at 300 rpm for 30 seconds (steps 41 and 42). The wafer is baked at 150 ° C. for 30 minutes to solidify the photoresist (step 43). This wafer is immersed in a 20% potassium hydroxide aqueous solution (85 ° C.) for 4 hours (step 44) to etch the silicon and open the ink supply slot 13 (FIG. 7).

As a result, the thermal head pattern for the ink jet printer on the wafer surface was protected even after the etching. Further, even if the photoresist coating and solidification were not performed a plurality of times, the photoresist was coated thickly and pinholes were eliminated, and the reliability was improved. Viscosity 10
The effect is great when it is 0 cp or more. When the step of the circuit pattern is large, the viscosity is preferably large.

FIG. 10 is a process diagram showing a fourth embodiment of the etching method according to the present invention. On the circuit pattern surface side of the wafer 1 (FIG. 1) on which the thermal head pattern for the ink jet printer is formed, 5000-5000 DuPont (manufactured) VM-651 as an adhesion promoter of aminosilane type is applied.
Spin coating is performed at rpm of 30 seconds (step 52). The wafer is baked at 150 ° C. for 30 minutes to solidify the photoresist (step 53). Up to this point is the step of protecting the circuit pattern of the wafer 1. Next, this wafer is dipped in a 20% aqueous potassium hydroxide solution (85 ° C.) for 4 hours (step 54) to etch the silicon, and the ink supply slot 13 Open (Fig. 7).

As a result, the thermal head pattern for the ink jet printer on the wafer surface was protected even after the etching. Further, even when the photoresist is applied thickly because the step difference of the circuit pattern is large, the peeling of the photoresist around the wafer can be prevented.

FIG. 11 is a process diagram showing a fourth embodiment of the etching method according to the present invention.

First, as an aminosilane-based adhesion promoter mixed with an alcohol-based solvent containing water,
VM-651, 1-methoxy-2-propanol and water are mixed at 1: 180: 20 (step 61). On the side of the circuit pattern surface of the wafer 1 (FIG. 1) on which the thermal head pattern for the ink jet printer is formed,
Spin-coat this mixture at 5000 rpm for 30 seconds 8
Bake at 5 ° C. for 5 minutes (step 62). Next, OM of Tokyo Ohka (manufactured by) as a rubber + bisazito type photoresist
Using R-83, spin coating is performed at 300 rpm for 30 seconds (step 63). The wafer is baked at 150 ° C. for 30 minutes to solidify the photoresist (step 63). The process up to this point is the circuit pattern protection process for the wafer 1. Next, this wafer is immersed in a 20% aqueous potassium hydroxide solution (85 ° C.) for 4 hours (step 64) to etch the silicon and open the ink supply slot 13 (FIG. 7).

As a result, the thermal head pattern for the ink jet printer on the wafer surface was protected even after the etching. Further, even when the photoresist is applied thicker because the step difference of the circuit pattern is larger, the photoresist around the wafer can be prevented from peeling off.

[0021]

As described above, according to the present invention, when a circuit pattern formed on a silicon wafer is protected, no jig is required, so that automation is easy and productivity is high. There is.

[Brief description of drawings]

FIG. 1 is a process diagram showing a first embodiment of an etching method according to the present invention.

FIG. 2 is a plan view showing a silicon wafer to be etched, where (a) is the front surface, (b) is the back surface, and (c) is A of (a).
FIG.

FIG. 3 is a front view showing a dropping state of a rubber + bis-azist photoresist.

FIG. 4 is a front view of a state where the film thickness is made uniform by spin.

FIG. 5 is a cross-sectional view showing a baked state of a rubber + bis-azide photoresist.

FIG. 6 is a cross-sectional view showing a state in which a silicon wafer is immersed in an etching solution after baking.

7A and 7B are plan views of a silicon wafer in which slots are formed by etching, FIG. 7A is a front surface, and FIG. 7B is an enlarged view of part A of FIG.

FIG. 8 is a process diagram showing a second embodiment of the etching method according to the present invention.

FIG. 9 is a process drawing showing a third embodiment of the etching method according to the present invention.

FIG. 10 is a process drawing showing a fourth embodiment of the etching method according to the present invention.

FIG. 11 is a process drawing showing a fifth embodiment of the etching method according to the present invention.

FIG. 12 is a cross-sectional view showing a circuit pattern protection state of a conventional silicon wafer.

[Explanation of symbols]

 1 Silicon Wafer 2 Silicon Nitride 13 Slot

Claims (8)

[Claims] 1. A rubber + bisazito-based photoresist is applied to the surface of a silicon wafer having a circuit pattern on which the circuit pattern is formed, and baked to solidify, whereby potassium hydroxide, which is an etching solution for silicon, is applied. A method of protecting a circuit pattern formed on a silicon wafer, comprising protecting the circuit pattern formed on the silicon wafer from an aqueous solution. 2. The method for protecting a circuit pattern formed on a silicon wafer according to claim 1, wherein the steps of applying the rubber + bisazito type photoresist, baking and solidifying are performed a plurality of times. 3. The method of protecting a circuit pattern formed on a silicon wafer according to claim 2, wherein the rubber + bisazito type photoresist has a viscosity of 100 cp or more. 4. An aminosilane-based adhesion promoter is applied to the surface of a silicon wafer having a circuit pattern on which the circuit pattern is formed, and then a rubber + bisazito photoresist is applied and baked to solidify. A method for protecting a circuit pattern formed on a silicon wafer, comprising protecting the circuit pattern from an aqueous potassium hydroxide solution which is an etching solution for silicon. 5. A rubber + bisazit is prepared by applying a mixture of an aminosilane-based adhesion promoter and an alcohol-based solvent containing water to the surface of the silicon wafer on which the circuit pattern is formed, on which the circuit pattern is formed. A method for protecting a circuit pattern formed on a silicon wafer, comprising protecting the circuit pattern from an aqueous solution of potassium hydroxide, which is an etching solution for silicon, by applying and baking a system photoresist to solidify. 6. A rubber + bisazit is formed by forming a film that does not react with potassium hydroxide, which is an etching solution, on the surface opposite to the one surface of a silicon wafer having a circuit pattern formed on one surface according to the shape to be etched. An etching method comprising applying a photoresist of a system to a surface of the silicon wafer on which the circuit pattern is formed, baking and solidifying the photoresist, and then immersing the photoresist in a potassium hydroxide aqueous solution which is an etching solution for silicon. 7. A silicon wafer having a circuit pattern formed on one surface thereof is formed on a surface opposite to the one surface thereof with a film that does not react with potassium hydroxide as an etching solution according to a shape to be etched. An adhesion promoter is applied to the surface of the silicon wafer on which the circuit pattern is formed, and then a rubber + bisazito photoresist is applied, baked and solidified, and then immersed in an aqueous solution of potassium hydroxide, which is an etching solution for silicon. An etching method characterized by the above. 8. A silicon wafer having a circuit pattern formed on one surface thereof is formed on a surface opposite to the one surface thereof with a film that does not react with potassium hydroxide as an etching solution in accordance with a shape to be etched. A mixture of an alcohol solvent containing water and an adhesion promoter is applied to the surface of the silicon wafer on which the circuit pattern is formed, and then a rubber + bisazito photoresist is applied and baked to solidify the silicon. Etching method is characterized by immersing in an aqueous solution of potassium hydroxide which is the etching solution of.