JPH11233794A - Manufacture of micro-sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing micro-sensor device by which the mass-productivity of a micro-sensor device can be improved by improving a silicon substrate etching process. SOLUTION: In a method for manufacturing micro-sensor device, a photosensitive SOG film 12 mask on a first silicon substrate 11 is patterned as a mask and a cantilever type probe 13 is formed in a projecting pattern on the silicon substrate 11 by etching the substrate with a KOH solution by using the SOG film 12 as the mask. Then an insulating film is deposited on the surface of the substrate 11 on which the projecting pattern is formed so as to cover the surface and, after a second silicon substrate is stuck to the first silicon substrate 11 in one body with the deposited insulating film in between, the substrate 11 is polished until the deposited insulating film is exposed. Then, after the probe 13 is worked to such a state that the probe 13 is surrounded by the deposited insulating film, the unnecessary part of the second silicon substrate is etched off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a microsensor device such as a cantilever probe by processing a silicon substrate.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a micromachining technique for processing a fine hole in a precision machine part or the like. When a fine hole is processed by micromachining, a technique for precisely measuring the diameter and the like of the fine hole is required. As a technique for measuring the diameter of such a fine hole, various techniques using a cantilever-type probe have been proposed (for example, see Japanese Unexamined Patent Publication No.
243313, JP-A-8-75445, etc.).

As a method of processing a cantilever probe using a silicon substrate, for example, there is a method using an SOI (Silicon On Insulator) substrate utilizing a substrate bonding technique. In brief, the method of manufacturing the probe is as follows. First, a first silicon substrate as a probe material and a second silicon substrate for backing are bonded together via an insulating film such as an oxide film. Next, after the first silicon substrate is polished to a required thickness as a probe, a mask is patterned and the silicon substrate is etched to form a probe.
A strong alkaline solution such as KOH is used for etching the silicon substrate.
A silicon nitride film (SiNx film) is used.

Thereafter, unnecessary portions of the backing second silicon substrate are removed by etching, thereby obtaining a pair of thin needle-like probes in a state integrated with the remaining base of the silicon substrate. Also for the etching of the second silicon substrate, etching with a KOH solution using a SiNx film is used. A metal film is formed on the surface of the probe. For example, if the cantilever-type probe made in this way is used for measuring a minute inner diameter of about 1 mm, the diameter of one probe is approximately 20 μm, the interval between a pair of probes is 80 μm, and the length is 1 mm. It becomes small.

[0005]

As described above, in the conventional probe manufacturing process using a bonded substrate, when etching a silicon substrate, a SiNx film mask by a low-pressure CVD method is used. This is an annealing step in which the temperature is about 800 ° C. and the processing time is several hours, and the processing apparatus is expensive. Further, even if the etching of the backing silicon substrate is allowed to some extent in the probe etching process, it is necessary to prevent the already processed probe from being etched when etching the backing silicon substrate. For this purpose, for example, it is necessary to form a SiNx film on both sides. However, since the surface of the already processed probe must be covered with a SiNx film and finally removed again, the process is complicated. Become. Moreover, it takes a long time to etch the backing silicon substrate,
Even if the probe processed by the x film is covered, if a part of the probe is exposed on the side surface, there is a problem that the side etching progresses and the probe shape is greatly damaged.

The present invention has been made in view of the above circumstances, and has as its object to provide a method of manufacturing a microsensor device that can improve mass productivity by improving a silicon substrate etching process.

[0007]

According to the present invention, there is provided a method of manufacturing a microsensor device by patterning a mask on a silicon substrate and etching unnecessary portions of the silicon substrate with a strong alkaline solution using the mask. The pattern of the mask is formed with a coating type insulating film by spin coating. More specifically, a method of manufacturing a microsensor device according to the present invention includes forming a pattern of a coating type insulating film mask on a first silicon substrate by spin coating, and using the mask to form a strong alkali on the first silicon substrate. Processing the microsensor body as a convex pattern on the first silicon substrate by etching with a liquid, and forming a deposited insulating film so as to cover the surface of the first silicon substrate on which the convex pattern is formed Bonding a second silicon substrate thereon to integrate the first and second silicon substrates via a deposited insulating film, and removing the first silicon substrate until the deposited insulating film is exposed. Polishing, processing the microsensor body so that its periphery is surrounded by the deposited insulating film;
Etching and removing unnecessary portions of the second silicon substrate.

[0008] The method of manufacturing a microsensor device according to the present invention also includes a step of bonding a first silicon substrate and a second silicon substrate together with an insulating film interposed therebetween, and integrating the first silicon substrate and the second silicon substrate. Patterning a mask of a coating type insulating film by spin-coating, patterning the microsensor body by etching the first silicon substrate with a strong alkaline solution using the mask, And etching off unnecessary portions. Preferably, the present invention is characterized in that the coating type insulating film has photosensitivity and is patterned by direct exposure. Further, in the step of etching and removing unnecessary portions of the second silicon substrate, preferably, a mask of a coating type insulating film is formed on the second silicon substrate by spin coating, and etching is performed using a strong alkaline solution using the mask. Shall be.

According to the present invention, by using a coating type insulating film as a mask for etching a silicon substrate,
Compared to the case of using a SiNx film formed by low-pressure CVD, a large-scale apparatus is not required, and the film formation time is significantly reduced. Therefore, the manufacturing process of the microsensor device using the bonded substrate is simplified, and the mass productivity of the microsensor device is improved. In particular, when a photosensitive material is used as the coating-type insulating film, the mask can be patterned by direct exposure without using a resist process, and the process can be further simplified.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to the manufacture of a cantilever probe will be described below with reference to the drawings. In an actual manufacturing process, a plurality of pairs of cantilever-type probes are formed from one substrate. However, in the following drawings, description will be made focusing on a pair of cantilever-type probes for convenience. As shown in FIG. 1, in this embodiment, a coating type insulating film formed by spin coating, that is, a SOG (Spin On Glass) film is formed on a first silicon substrate 11 serving as a microsensor substrate as an etching resistant mask material. 12 is formed.
The SOG film 12 preferably has photosensitivity.

Next, as shown in FIG. 2, the SOG film 12 is exposed and developed to form a mask pattern. SOG film 1
When 2 has photosensitivity, it can be exposed and developed directly without using a resist process. And
Using the patterned SOG film 12 as a mask, FIG.
As shown in (1), the silicon substrate 11 is etched using a strong alkaline solution, for example, KOH, to form the probe 13 as a convex pattern so as to be integrated with the silicon substrate 11. After that, the SOG film 12 used as a mask
Is removed. The shape obtained as described above is shown in a perspective view in FIG. At this stage, the probe 13 has not been separated from the silicon substrate 11.

Next, as shown in FIG. 5, a deposited insulating film 14 is formed so as to cover the probe 13 formed as a convex pattern. Then, as shown in FIG. 6, a second silicon substrate 15 is bonded on the deposited insulating film 14 as a backing substrate. The deposited insulating film 14 is preferably a layer of Si-BO fine particles (soot) obtained by a flame hydrolysis method. This fine particle layer becomes a hard deposited insulating film 14 by bonding substrates and annealing at 1150 to 1250 ° C. as shown in FIG.
15 will be firmly bonded. This method is known as a method capable of performing good substrate bonding even when the bonding surface has irregularities.

After bonding the backing silicon substrate 15 to the silicon substrate 11 thus processed, the first silicon substrate 11 is removed until the deposited insulating film 14 is exposed as shown in FIG. Grind. Thus, the pair of probes 13 are separated from each other while being surrounded by the deposited insulating film 14.

Next, unnecessary portions of the second silicon substrate 15 are removed by etching. Specifically, for example, as shown in FIG. 8, an SOG film 16 is formed on a second silicon substrate 15 and exposed and developed, and as shown in FIG. 16 masks are patterned. The SOG film 16 is preferably made of a photosensitive material and patterned by direct exposure, as in the case of processing the first silicon substrate 11 described above.

Then, using the SOG film 16 as a mask, the second silicon substrate 1 is formed with a strong alkaline solution, for example, KOH.
5 is etched. At this time, as shown in FIG. 9, the probe 13 which has already been processed has its periphery covered with the deposited insulating film 14, so that side etching is prevented. Finally, if the deposited insulating film 14 is removed, FIG.
As shown in FIG. 7, the probe 13 can be exposed. Then, the SOG film 16 is removed, and as shown in FIG.
By coating 7, a cantilever probe as a conductive structure is completed.

As described above, in this embodiment, before bonding the substrates, a convex pattern serving as a probe is processed on the first silicon substrate, and the processed surface is covered with the deposited insulating film to form the second pattern. By bonding a silicon substrate and then polishing the first silicon substrate, the probe is separated while being embedded in the deposited insulating film. Therefore, in the step of etching the second silicon substrate for lining, the probe already processed is surrounded by the deposited insulating film, so that the side etching does not progress even if the KOH etching is performed for a long time. And a small probe as designed can be obtained.

In this embodiment, a SOG film is used as an etching mask for a silicon substrate,
As compared with the case where a SiNx film is used, a large-scale and expensive apparatus is not required, and the film formation time is reduced by about one hour. Therefore, the throughput is improved. In particular, when a photosensitive SOG film is used, exposure and development can be performed without performing a resist process, and thus the mask patterning process is simplified, which is more preferable.

FIGS. 13 to 18 show a cantilever manufacturing process according to another embodiment of the present invention. In this example,
First, the substrate is bonded as in the conventional case. That is, FIG.
As shown in FIG. 1, a first silicon substrate 2 for a cantilever
1 and a second silicon substrate 23 for lining are bonded together with an insulating film 22 interposed therebetween to be integrated. Specifically, the insulating film 2
2 is previously formed on one surface of the silicon substrates 21 and 23 with a thermal oxide film or a CVD silicon oxide film,
Thereafter, they are integrated by direct bonding. In this embodiment, since the bonding surface is not processed yet and is flat, direct bonding can be performed without using a deposited insulating film formed by the flame hydrolysis method as in the previous embodiment.

Next, as shown in FIG. 14, the first silicon substrate 21 is polished to a required thickness. And
As shown in FIG. 15, a mask made of the SOG film 24 is patterned, and the silicon substrate 21 is etched with KOH using the mask. As shown in FIG.
To process. The SOG film 24 is preferably made of a photosensitive material and patterned by direct exposure, as in the previous embodiment. FIG. 17 shows this state in a perspective view for easy understanding.

Finally, as shown in FIG. 18, unnecessary portions of the second silicon substrate 23 are removed by etching, and the insulating film 22 is further removed by etching to complete a cantilever probe. Although not shown in the figure, KOH etching is also performed in the etching process of the second silicon substrate 22 using the photosensitive SOG film as a mask. In this embodiment, as in the previous embodiment, the etching process is simplified by performing KOH etching using the SOG film as a mask.

The present invention is not limited to the above embodiment. In the embodiment, the example in which the cantilever probe is manufactured has been described. However, the present invention can be similarly applied to the manufacture of an acceleration sensor device as shown in FIG. 12 and other various microsensor devices.

[0022]

As described above, according to the present invention, the use of the SOG film as a mask for etching a silicon substrate requires a larger film forming apparatus than the case of using a SiNx film by low pressure CVD. In addition, the film formation time is greatly reduced. Therefore, the manufacturing process of the microsensor device using the bonded substrate is simplified, and the mass productivity of the microsensor device is improved. When a photosensitive SOG film is used, a mask can be pattern-formed by direct exposure without using a resist process, and the process can be further simplified.

[Brief description of the drawings]

FIG. 1 shows a step of manufacturing a cantilever probe according to an embodiment of the present invention.
It is sectional drawing which shows the state which applied the film.

FIG. 2 is a cross-sectional view showing a state where an SOG film is patterned in the same manufacturing process.

FIG. 3 is a cross-sectional view showing a state where a probe is patterned by etching a first silicon substrate in the same manufacturing process.

FIG. 4 is a perspective view showing a probe pattern formed in the same manufacturing process.

FIG. 5 is a cross-sectional view showing a state where a deposited insulating film is formed in the same manufacturing process.

FIG. 6 is a cross-sectional view showing a state where a second silicon substrate is bonded in the manufacturing process.

FIG. 7 is a cross-sectional view showing a state where a probe is separated by polishing a first silicon substrate in the same manufacturing process.

FIG. 8 is a cross-sectional view showing a state where an SOG film is formed on a second silicon substrate in the same manufacturing process.

FIG. 9 is a perspective view showing a state where a pattern is formed using an SOG film as a microphone in the same manufacturing process.

FIG. 10 is a perspective view showing a state where a second silicon substrate is etched in the same manufacturing process.

FIG. 11 is a perspective view showing a probe obtained by the same manufacturing process.

FIG. 12 is a diagram illustrating an acceleration sensor device according to another embodiment.

FIG. 13 is a cross-sectional view showing a state of bonding substrates in a manufacturing process according to another embodiment of the present invention.

FIG. 14 is a cross-sectional view showing a state of substrate polishing in the same manufacturing process.

FIG. 15 is a cross-sectional view showing a mask pattern forming step in the same manufacturing step.

FIG. 16 is a cross-sectional view showing a probe processing step by the same manufacturing step.

FIG. 17 is a perspective view showing the state of FIG. 16;

FIG. 18 is a perspective view showing a state where a backing silicon substrate is removed.

[Explanation of symbols]

11 ... first silicon substrate (microsensor substrate),
12: SOG film, 13: probe, 14: deposited insulating film,
15 ... second silicon substrate (backing substrate), 16 ... S
OG film, 17: metal film, 21: first silicon substrate, 2
2 ... insulating film, 23 ... second silicon substrate, 24 ... SOG
Membrane, 25 ... probe.

Claims (5)

[Claims] 1. A method of manufacturing a microsensor device by patterning a mask on a silicon substrate and etching an unnecessary portion of the silicon substrate with a strong alkaline solution using the mask, wherein the mask is formed by spin coating. A method for manufacturing a microsensor device, comprising forming a pattern with an insulating film. 2. A pattern of a coating type insulating film mask formed by spin coating on a first silicon substrate, and etching the first silicon substrate with a strong alkaline solution using the mask to form the microsensor main body. Processing a convex pattern on the first silicon substrate; forming a deposited insulating film so as to cover the surface of the first silicon substrate on which the convex pattern is formed; and forming a second silicon substrate on the deposited insulating film. Bonding and integrating the first and second silicon substrates via a deposited insulating film; and polishing the first silicon substrate until the deposited insulating film is exposed, thereby surrounding the microsensor main body. Processing a state surrounded by the deposited insulating film; and etching and removing an unnecessary portion of the second silicon substrate. Vice manufacturing method. 3. A step of bonding a first silicon substrate and a second silicon substrate together with an insulating film interposed therebetween to integrate the first silicon substrate and the second silicon substrate, and applying a coating type insulating film mask to the first silicon substrate by spin coating. Forming a pattern, etching the first silicon substrate with a strong alkaline solution using the mask to pattern the microsensor body, and etching and removing unnecessary portions of the second silicon substrate. A method for manufacturing a microsensor device, comprising: 4. The method for manufacturing a microsensor device according to claim 1, wherein the coating type insulating film has photosensitivity and is formed by direct exposure. 5. The step of etching and removing unnecessary portions of the second silicon substrate includes forming a coating type insulating film mask by spin coating on the second silicon substrate, and using the mask to form the second silicon substrate. 4. The silicon substrate is etched with a strong alkaline solution.
Or the method for manufacturing a microsensor device according to 4.