JPH04256861A - Manufacture of semiconductor gas flow path - Google Patents

Abstract

PURPOSE:To prevent the shortening of the length of a nozzle hole which is formed by etching by providing protruding parts which protrude in the gas flowing direction of a gas flow path at a part wherein the half hole of the nozzle hole of a mask pattern is formed. CONSTITUTION:Protruding parts 251 and 252 which protrude in the gas flowing direction of a gas flow path are provided without shielding a nozzle-hole forming region at outer corner parts 201 and 202 at a part of a mask pattern 22 where the half hole of the nozzle hole is formed. The length of the protruding parts 251 and 252 are set so that the length 13 becomes about twice the etching depth. Etching is performed so as to form the half hole of the nozzle hole and the half groove of the gas flow path in a semiconductor substrate by using the mask pattern 22 such as this. Then, places corresponding to the protruding parts 251 and 252 of the mask pattern 22 undergo overetching. However, the length of the overetched part becomes approximately equal to the length 23 of the protruding parts 251 and 252, and the overetched part does not intrude into the nozzle-hole forming region.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor gas flow path in which gas is ejected from a nozzle hole formed in a semiconductor substrate to generate a gas flow in the gas flow path.

0002

2. Description of the Related Art Generally, this type of semiconductor gas flow path is used, for example, as a gas flow path in a miniaturized gas type angular velocity detector.

As shown in FIG. 18, the gas type angular velocity detector has a gas flow ejected from a nozzle hole 9 into a gas passage 10 toward a pair of flow sensors 11 in a sealed casing 8. As shown in FIG. 19, when a lateral angular velocity ω is applied to the detector body and the gas flow deviates from the center line O-O and is deflected to one side, the temperature coefficient of resistance in the flow sensor 11 is large. The difference in temperature sensing output produced between a pair of heat wires 111 and 112 made of tungsten or the like is extracted to detect the direction and magnitude of the angular velocity ω acting on the detector body at that time.

In the figure, reference numeral 12 denotes a diaphragm type pump, which circulates and sends the gas contained in the casing 8 to the nozzle hole 9 and the gas passage 10 through the flow path 13. Further, 8 is a rectifying hole that rectifies the gas ejected from the nozzle hole 9 into the gas passage 10, and 15 is a pair of heat wires 111, 11 in the flow sensor 11.
This circuit board is mounted with an electric circuit for detecting the direction and magnitude of the angular velocity ω acting on the detector body by extracting the difference between the temperature sensing outputs generated in the detector body.

However, in such a gas type angular velocity detector, when the angular velocity ω does not act on the detector body, the gas flow ejected from the nozzle hole 9 into the gas passage 10 flows through the nozzle hole 9 and the gas The nozzle hole 9 and the gas passage 10 are arranged so that the gas flows straight along the center line O-O of the passage 10.
It is necessary to form a sensor, and the processing accuracy is directly linked to the detection accuracy.

[0006] Conventionally, therefore, as shown in FIGS. 6 to 9, a micromachining process technique by etching a semiconductor substrate using a mask pattern is used.
A half-hole 31 of the nozzle hole and a half-groove 41 of the gas passage, respectively.
By abutting the lower semiconductor substrate 1 and the upper semiconductor base 2 formed by etching, the nozzle hole 3 is formed.
The semiconductor gas flow path consisting of the gas path 4 and the gas path 4 is manufactured with high processing accuracy, and the detector is thereby miniaturized (see Japanese Patent Application No. 1-165762).

Here, the lower semiconductor substrate 1 forming a part of the gas passage 4 is etched to form a bridge part 6 spanning the gas passage 4, and a pair of heat wires 51 are attached to the upper surface of the bridge part 6. , 52 are patterned by means such as metal deposition. The bridge portion 6 is provided so as to be located approximately in the middle of the height of the gas passage 4. Further, on the semiconductor substrate 1 at both ends of the bridge portion 6, electrode portions 7 connected to the respective heat wires 51 and 52 are patterned by means such as metal vapor deposition. Furthermore, a micropump 16 using a piezo element as a driving source is integrated and formed in a portion of the lower semiconductor substrate 1 at the back of the downstream side of the heat wires 51 and 52 in the gas passage 4.

Generally, in anisotropic etching of a silicon semiconductor substrate using an alkaline aqueous solution such as KOH, (001)
The etching speed difference between the (111) plane and the (111) plane is significantly different, and as shown in FIGS. Since grooves 18 or recesses 19 can be easily formed in the semiconductor substrate 1 according to the conditions, this method is widely used in micromachining of semiconductor substrates. In the figure, a is the (001) plane of the semiconductor substrate 1, and b is the (1) plane of the semiconductor substrate 1.
11) Shows the surface.

However, according to the anisotropic etching,
As shown in FIGS. 14 and 15, in the outer corner portion 20 of the mask pattern 17, the (221) plane, the (51
1) There is a problem that a high-order side-etched surface c such as a surface appears, resulting in an over-etched state. In the figure, 21 indicates an over-etched region.

0010

[Problems to be Solved by the Invention] Therefore, by using a mask pattern 17 having a shape as shown in FIG. When etching is performed to form the half-grooves 41 of the passages, as shown in FIG. The upper length l2 becomes short, and the length of the nozzle hole 3 that sends the gas flow into the gas passage 4 becomes insufficient, causing turbulent flow, which is a constraint on the gas flow path design. .

For example, width w=0.4 mm, length l=1 m
Assuming a nozzle hole with m and depth d = 0.2 mm, the actual length l2 of the nozzle hole is because the length l1 of the over-etched portions at both ends is approximately twice the etching depth d. , l2=0.2 mm.

0012

[Means for Solving the Problems] The present invention provides a method for forming half holes of nozzle holes and half grooves of gas passages in a semiconductor substrate by etching the semiconductor substrate according to a mask pattern. A special mask pattern is used in which a protrusion is provided at the outer corner of the part where the hole is to be formed so as to protrude in the gas flow direction of the gas passage without blocking the nozzle hole forming area.

[0013]

[Operation] According to the present invention, when etching a semiconductor substrate, a portion corresponding to the protrusion provided protrudingly as described above is formed at the outer corner portion of the portion of the mask pattern for forming the half hole of the nozzle hole. The length of the nozzle hole formed by etching is prevented from becoming short by preventing over-etching from entering the nozzle hole forming region.

[0014]

[Example] Fig. 1 shows an example of a mask pattern 22 used in the present invention, in which a nozzle hole forming region 23 is blocked by outer corner portions 201 and 202 of a portion for forming a half hole of a nozzle hole. Projections 251 and 252 are provided that project in the gas flow direction of the gas passage. In the figure, 24 indicates a gas passage forming region.

Specifically, when etching is performed by placing the mask pattern 22 on the (001) plane of a silicon semiconductor substrate, for example, the protrusions 251 and 252 are aligned in the <110> direction (of the nozzle hole) of the semiconductor substrate. (formation direction).

The length l3 of the protrusions 251 and 252 is set to be approximately twice the etching depth d. Further, the width of the protrusions 251 and 252 is set to be as thin as possible (usually several μm is sufficient).

When the semiconductor substrate is etched using such a mask pattern 22 to form a half hole for a nozzle hole and a half groove for a gas passage, the mask pattern 22
The portions corresponding to the protrusions 251 and 252 are over-etched, but the length of the over-etched portion corresponding to the etching depth generated on the semiconductor substrate at that time is approximately equal to the length l3 of the protrusions 251 and 252. , over-etching does not enter the nozzle hole formation region.

[0018] Then, a predetermined depth d with respect to the semiconductor substrate is set.
When etching is done, the protrusions 251, 252
The portion of the semiconductor substrate corresponding to the etching is completely removed by over-etching, leaving no remaining etched portion.

Therefore, even if the semiconductor substrate is etched with the protrusions 251 and 252 provided on the mask pattern 22, there will be no problem in forming the half-groove of the gas passage.

Further, in the present invention, when the semiconductor substrate is etched using the mask pattern 22 to form the half-hole of the nozzle hole and the half-groove of the gas passage, the protrusions 251 provided on the mask pattern 22, Monitoring the etching state of the semiconductor substrate at the location corresponding to 252,
The completion of etching is detected when the portions of the semiconductor substrate corresponding to the protrusions 251 and 252 are completely removed by over-etching.

FIGS. 2 and 3 show mask pattern 2.
2 shows other examples of shapes of protrusions 251 and 252 provided in FIG.

Here, the shapes of the protrusions 251 and 252 are devised to more reliably prevent over-etching from entering the nozzle hole forming area, and
The portions of the semiconductor substrate corresponding to the protrusions 251 and 252 are completely removed by over-etching, so that the last etched portions are less likely to remain.

FIG. 4 shows the shape of the semi-hole of the nozzle hole on the gas passage side of the semiconductor substrate, which is etched using the mask pattern 22 provided with the protrusions 251 and 252. In the figure, the shaded area indicates the etched side surface of the semiconductor substrate.

FIG. 5 shows the shape of a semi-hole of a nozzle hole on the gas passage side of a semiconductor substrate etched using a conventional mask pattern.

Although not particularly shown in the drawings, rectifying holes (see FIG. 18) for rectifying the gas flow ejected into the gas passage 4 are provided on both sides of the nozzle hole 3 as needed. A half hole of the rectifying hole is formed in the upper semiconductor substrate 2 and the nozzle hole 3.
As in the case of forming half-holes, these can be formed by etching them respectively.

[Effects of the Invention] As described above, in the method of manufacturing a semiconductor gas passage according to the present invention, a half-hole for a nozzle hole and a half-groove for a gas passage are respectively formed by etching a semiconductor substrate using a mask pattern. When manufacturing a semiconductor gas flow path in which an upper semiconductor substrate and a lower semiconductor substrate are brought together to eject gas from a nozzle hole to generate a gas flow in the gas path, a half hole of the nozzle hole in a mask pattern is formed. Since the semiconductor substrate is etched using a mask pattern in which a protrusion that protrudes in the gas flow direction of the gas passage without blocking the nozzle hole formation area is provided on the outer corner portion of the nozzle hole formation area, the semiconductor substrate is etched. The advantage is that the etching does not enter the nozzle hole formation area, and the etching of the semiconductor substrate can be performed with good control, making it possible to form nozzle holes and gas passages with high precision without being subject to design constraints. It has several advantages.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a mask pattern used in the present invention.

FIG. 2 is a diagram showing another example of a mask pattern used in the present invention.

FIG. 3 is a diagram showing still another example of a mask pattern used in the present invention.

FIG. 4 is a plan view showing the shape of a semi-hole portion of a nozzle hole on the gas passage side of a semiconductor substrate etched using a mask pattern according to the present invention.

FIG. 5 is a plan view showing the shape of a semi-hole portion of a nozzle hole on the gas passage side of a semiconductor substrate etched using a conventional mask pattern.

FIG. 6 is a plan view showing a semiconductor substrate in which a half-hole of a nozzle hole and a half-groove of a gas passage are formed by etching.

FIG. 7 is a perspective view showing a semiconductor substrate in which a half-hole of a nozzle hole and a half-groove of a gas passage are formed by etching.

FIG. 8 is a perspective view showing a semiconductor gas flow path formed by abutting a lower semiconductor substrate and an upper semiconductor substrate in which half-holes of nozzle holes and half-grooves of gas passages are formed by etching.

9 is a cross-sectional view taken along line AA in FIG. 8. FIG.

FIG. 10 is a partial plan view of a mask pattern and a semiconductor substrate when forming a groove in the semiconductor substrate.

FIG. 11 is a sectional view taken along line AA in FIG. 10.

FIG. 12 is a partial plan view of a mask pattern and a semiconductor substrate when forming a recess in the semiconductor substrate.

FIG. 13 is a cross-sectional view taken along line AA in FIG. 12;

FIG. 14 is a plan view showing an etched state of a semiconductor substrate in a mask pattern having external corners.

15 is a cross-sectional view taken along line AA in FIG. 14. FIG.

FIG. 16 is a diagram showing a conventional mask pattern.

FIG. 17 is a plan view showing a state of over-etching that occurs in a half-hole portion of a nozzle hole when a conventional mask pattern is used.

FIG. 18 is a cross-sectional plan view showing a general configuration of a gas type angular velocity detector.

FIG. 19 is a diagram showing the deflection state of the gas flow when angular velocity is applied to the gas type angular velocity detector.

[Explanation of symbols]

1...Lower semiconductor substrate 2...Upper semiconductor substrate 3...Nozzle hole 31...half hole of nozzle hole 4...Gas passage 41...Half groove of gas passage 17...Mask pattern 20, 201, 202...Outer corner part 21...Over-etching area 251, 252...Protrusion part

Claims (4)

[Claims] 1. By etching the semiconductor substrate using a mask pattern, an upper semiconductor substrate and a lower semiconductor substrate, each having a half-hole for a nozzle hole and a half-groove for a gas passage, are brought into contact with each other, and a gas is then etched. When manufacturing a semiconductor gas flow path that generates a gas flow in a gas passage by ejecting from a nozzle hole, a mask is placed on the outer corner of the part of the mask pattern for forming the half hole of the nozzle hole without blocking the nozzle hole formation area. A semiconductor gas flow channel characterized in that a half-hole for a nozzle hole and a half-groove for a gas channel are formed in a semiconductor substrate using a mask pattern provided with a protrusion that projects in the gas flow direction of the gas channel. manufacturing method. 2. The method of manufacturing a semiconductor gas flow path according to claim 1, wherein the length of the protrusion of the mask pattern is approximately twice the etching depth of the half hole of the nozzle hole. 3. A mask pattern is placed on the (001) plane of the semiconductor substrate, and a nozzle hole and a protruding portion of the mask pattern are formed along the <110> direction of the semiconductor substrate. A method for manufacturing a semiconductor gas flow path according to item 1. 4. The method of manufacturing a semiconductor gas flow path according to claim 1, wherein the completion of etching is detected according to the etching state of the semiconductor substrate at a location corresponding to a protrusion of the mask pattern.