JPH11230707A - Manufacture of microsensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a microsensor device in which the form of a microsensor main body of a prove or the like after working is not damaged in the following etching process. SOLUTION: After a probe 13 is worked as a protruding pattern on a substrate by etching a first silicon substrate 11, a deposition insulating film 14 is formed so as to cover the surface on which the protruding pattern is formed. A second silicon substrate 15 for backing is stuck on the deposition insulating film 14, and both of the substrates are formed in a unified body. The first silicon substrate 11 is polished until the deposition insulating film 14 is exposed, and the probe 13 is worked in the state that the periphery of the probe 13 is surrounded by the deposition insulating film 14. After that, unnecessary parts of the silicon substrate 15 for backing are eliminated by etching.

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 or the like.

[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. FIGS. 13 to 1 show the probe manufacturing method.
8 will be described. First, as shown in FIG. 13, a silicon substrate 3 as a probe material and a backing silicon substrate 1 are bonded together via an insulating film 2 such as an oxide film. Next, as shown in FIG. 14, the silicon substrate 3 is polished to a required thickness as a probe, and then, as shown in FIG.
Is formed, and the silicon substrate 3 is etched to form the probe 5 as shown in FIG. A strong alkaline solution such as KOH is used for etching the silicon substrate 3. In this case, a silicon nitride film (SiNx film) formed by a low pressure CVD method is used as the mask 4.

FIG. 17 is a perspective view showing the pattern of the processed probe 5 for easy understanding. Thereafter, by removing unnecessary portions of the backing silicon substrate 1 by etching, a pair of thin needle-like probes 5 are integrated with the remaining base of the silicon substrate 1 as shown in FIG. can get. The silicon substrate 1 is also etched by a KOH solution using a SiNx film. Although not shown in the drawing, a metal film is formed on the surface of the probe 5. For example, if the cantilever-type probe manufactured 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 distance between a pair of probes is 80 μm, and the length is 1 μm.
mm.

[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 1 in the etching step of FIG. 15 is allowed to some extent, it is necessary to prevent the probe 5 already processed from being etched when etching the backing silicon substrate 1. For this purpose, for example, it is necessary to form a SiNx film on both surfaces. However, since the surface of the probe 5 already processed must be covered with the SiNx film and finally removed again, the process is complicated. become. Moreover, since it takes a long time to etch the backing silicon substrate 1, even if the probe side processed by the SiNx film is covered, if a part of the probe is exposed on the side surface, the side etching proceeds. There is a problem that the shape of the probe is greatly impaired.

The present invention has been made in view of the above circumstances, and provides a method of manufacturing a microsensor device in which the shape of a processed microsensor body such as a probe is not damaged in a subsequent etching step. It is intended to provide.

[0007]

According to the present invention, there is provided a method of manufacturing a microsensor device, comprising the steps of: etching a microsensor substrate to process a microsensor body as a convex pattern on the substrate; Forming a deposited insulating film so as to cover the surface on which the convex pattern is formed, bonding a backing substrate thereon, and integrating the microsensor substrate and the backing substrate via the deposited insulating film; Polishing the microsensor substrate until the deposited insulating film is exposed, and processing the microsensor body so that its periphery is surrounded by the deposited insulating film; and etching unnecessary portions of the backing substrate. Removing step. In the present invention, the microsensor substrate and the backing substrate are, for example, silicon substrates. The deposited insulating film is preferably deposited as insulating fine particles by a flame hydrolysis reaction, and is cured by annealing in a step of bonding and integrating the microsensor substrate and the backing substrate.

In the manufacturing method according to the present invention, before bonding the microsensor substrate and the backing substrate, the microsensor body is processed as a convex pattern on the substrate.
Then, the convex pattern is covered with the deposited insulating film, the substrate for the macrosensor is bonded to the substrate for the backing via the deposited insulating film, and the substrate for the microsensor is polished to form the main part pattern of the microsensor body around the substrate. Is processed so as to be surrounded by the deposited insulating film. Therefore, in the subsequent step of etching unnecessary portions of the backing substrate, the periphery of the microsensor body is surrounded by the deposited insulating film, so that the shape of the microsensor body is not damaged by side etching. Thereby, it becomes possible to manufacture a micro sensor device having a minute shape as designed.

[0009]

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 the backing silicon substrate 15 is bonded 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 treated 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 a pair of probes 13 is coated with a metal film 17 such as an Au / Cr laminated film as shown in FIG. 11, thereby completing a cantilever-type probe as a conductive structure.

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, an 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.

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 applied to the manufacture of an acceleration sensor device as shown in FIG. 12 and other various microsensor devices. Further, in the embodiment, the microphone sensor body is processed with the silicon substrate, and the silicon substrate is used as the backing substrate. However, the present invention is also effective when other substrate materials are used. Further, the present invention is also effective in the case where a silicon substrate is etched using a SiNx film or the like as a mask instead of the SOG film as in the related art.

[0018]

As described above, according to the present invention, before bonding the microsensor substrate and the backing substrate, the microsensor body is processed as a convex pattern on the substrate, and this convex pattern is deposited. Covered with an insulating film, the macrosensor substrate is bonded to the backing substrate via this deposited insulating film, and the microsensor substrate is polished to process the microsensor body so that it is embedded in the deposited insulating film. . Therefore, in the step of etching unnecessary portions of the backing substrate, the microsensor body is protected by the deposited insulating film and is not side-etched. Thereby, it becomes possible to manufacture a micro sensor device having a minute shape as designed.

[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 by a conventional manufacturing process.

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

FIG. 15 is a cross-sectional view showing a mask pattern forming process according to a conventional manufacturing process.

FIG. 16 is a cross-sectional view showing a probe processing step by a conventional 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.

Claims (3)

[Claims] A step of etching the microsensor substrate to process the microsensor body as a convex pattern on the substrate; and depositing an insulating film so as to cover a surface of the microsensor substrate on which the convex pattern is formed. Forming a backing substrate thereon, integrating the microsensor substrate and the backing substrate via a deposited insulating film, and polishing the microsensor substrate until the deposited insulating film is exposed. And processing the microsensor body so that its periphery is surrounded by the deposited insulating film; and etching and removing unnecessary portions of the backing substrate. Production method. 2. The method according to claim 1, wherein the microsensor substrate and the backing substrate are silicon substrates. 3. The deposited insulating film is deposited as insulating fine particles by a flame hydrolysis reaction, and is cured by annealing in a step of bonding and integrating the microsensor substrate and the backing substrate. Claim 1
Or the method for manufacturing a microsensor vise according to 2.