JPH118221A - Manufacturing method of micro device - Google Patents

Abstract

(57) [Summary] [Object] To bond semiconductor wafers together, it is possible to remove a protruding portion of an adhesive in a microstructured structure which cannot be removed by polishing. In a method of manufacturing a micro element by a micromachining process using a semiconductor wafer that requires a semiconductor wafer bonding step, the semiconductor wafers are bonded to each other with an adhesive, and then bonded by an etchant that melts the adhesive. A step of removing the adhesive which has protruded from the surface is taken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a micro device by micro machining using a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, in a gas rate sensor for detecting an angular velocity from a deflection state of a gas flow when an angular velocity motion is applied to a sensor body, or a current meter or a flow meter,
In order to reduce the size, a sensor body including a flow path of a fluid such as a gas is manufactured by micromachining using an IC manufacturing technology using a semiconductor wafer.

[0003] When a micro element such as a gas rate sensor body is manufactured by micro machining using a semiconductor wafer, for example, semiconductor wafers having grooves formed on at least one side are adhered to each other to form a flow path therebetween. Bonding of a semiconductor wafer has become an important step for forming and the like.

In this case, as a simple bonding method, the semiconductor wafers are bonded to each other by placing a sheet-like adhesive on the bonding surface of the semiconductor wafer or applying the adhesive.

However, if the semiconductor wafers are bonded to each other by using an adhesive, the adhesive protrudes from the bonding surface. At that time, for example, if the adhesive protrudes into the gas flow path in the gas rate sensor, the gas flow is disturbed, and the sensor accuracy is reduced.

For this reason, conventionally, various measures have been taken such as making the shape of the bonding surface such that the adhesive hardly protrudes, and bonding the adhesive in such a posture that the adhesive hardly flows out into the flow path. However, none of them can completely eliminate the protrusion of the adhesive.

[0007]

The problem to be solved is that, when manufacturing micro-elements such as a gas rate sensor main body by micro-machining using a semiconductor wafer, when the semiconductor wafers are bonded together, Since the adhesive is protruded from the bonding surface and cannot be denied, it is micronized, and the protruding into the gas flow path causes the gas flow to be disturbed and the accuracy of the gas rate sensor to be reduced. It will be noticeable.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a micro element by micromachining using a semiconductor wafer which requires a bonding step of the semiconductor wafer. An optimal process for a micro element is employed in which the adhesive which has protruded from the bonding surface is removed by an etching solution which melts the adhesive.

[0009]

FIG. 1 shows a gas flow path in a gas rate sensor as an example of a micro device manufactured by micro machining.

Here, the upper semiconductor wafer 1 and the lower semiconductor wafer 2 each having a groove formed by etching, respectively.
Are bonded by an adhesive so that the gas flow path 3 is formed between the grooves.
In the figure, reference numeral 4 denotes the bonding portion. Note that the groove serving as the gas flow path may be formed in at least one of the semiconductor wafers.

When the upper semiconductor wafer 1 and the lower semiconductor wafer 2 are bonded by an adhesive, the adhesive protrudes from the bonding portion 4 and the adhesive 5 protrudes into the gas flow path 3. Is a factor that disturbs the gas flow.

The protruding portion 5 of the adhesive into the gas flow path 3 cannot be removed by polishing because the gas flow path 3 is micronized.

Therefore, according to the present invention, after the upper semiconductor wafer 1 and the lower semiconductor wafer 2 are bonded by an adhesive, the adhesive is immersed in an etching solution for melting, and the protruding portion 5 of the adhesive is chemically formed. I try to remove it.

At this time, for example, when the adhesive is an epoxy-based adhesive, a mixed solution of flowing acid and hydrogen peroxide is used as an etching solution.

The gap at the bonding portion 4 between the upper semiconductor wafer 1 and the lower semiconductor wafer 2 is usually 10 to 10.
It is about 20 μm, and the protruding amount of the adhesive therefrom is about 100 μm or less.

In this case, an etching solution having a mixing ratio of flowing acid and hydrogen peroxide solution of 1: 1 is applied at 60 ° C. (40-80 ° C.).
The upper semiconductor wafer 1 and the lower semiconductor wafer 2 are immersed in the etchant for 30 seconds (20 to 50 seconds).

In a normal semiconductor wafer bonding step, the gap between the semiconductor wafers after bonding is about 10 to 20 μm. Therefore, it takes a long time for the etching solution to penetrate into the bonding portion 4 in such a small gap. .

Therefore, even if the bonded upper semiconductor wafer 1 and lower semiconductor wafer 2 are immersed in an etching solution for a short time, the bonded portion 4 is not removed at all, and only the protruding portion 5 is removed. Is done.

As the adhesive, a silicone adhesive is widely used in addition to the epoxy adhesive. As the etching solution, an acid, an alkali, and a mixed solution thereof are used in addition to a mixed solution of a flowing acid and a hydrogen peroxide solution. Alternatively, an organic solvent such as acetone can be used as the etching solution.

[0020]

As described above, the present invention relates to a method of manufacturing a micro device by micro machining using a semiconductor wafer which requires a semiconductor wafer bonding step.
After bonding the semiconductor wafers with an adhesive, a step of removing the adhesive protruding from the bonding surface with an etchant that melts the adhesive is performed,
This is optimal for a micro element in which the protruding portion of the adhesive in a portion of the microstructured structure that cannot be removed by polishing can be removed without damaging the bonded portion.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an example of a micro device manufactured by micro machining.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper semiconductor wafer 2 Lower semiconductor wafer 3 Gas flow path 4 Adhesive part 5 Adhesive protruding part

Claims (1)

[Claims] 1. A method of manufacturing a micro device by micromachining using a semiconductor wafer which requires a semiconductor wafer bonding step, wherein an etching solution for bonding the semiconductor wafers to each other with an adhesive and then melting the adhesive. A method of removing the adhesive protruding from the bonding surface by the method.