JPH11350169A - Wet etching apparatus and wet etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide homogeneous precision parts by providing an etching apparatus capable of executing anisotropic etching in wet etching and a process for producing the same, thereby executing processing of fine sizes and making mass production. SOLUTION: This etching apparatus has a component section for ejecting a pressurized medicinal liquid 5 from a nozzle 4 and perpendicularly applying this medicinal liquid to a sample 1 surface and has a mechanism of splashing the medicinal liquid after processing from the sample surface by a high-pressure gas 6 or a mechanism of neutralizing the medicinal liquid as side etching progresses and anisotropic etching collapses if the medicinal liquid remains as it is in the processing section without being pressurized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for wet-etching materials such as semiconductor crystals, metals and glass plates with a chemical solution and a method of manufacturing the same.

[0002]

2. Description of the Related Art Wet etching is often used in the manufacturing process for precisely processing materials such as semiconductor crystals, metals and insulating films, and is still regarded as one of the important technologies. Wet etching is used for forming an arbitrary concavo-convex pattern on the surface of a sample, mirror finish of the surface of the sample, and polishing of a substrate. The shape of the concavities and convexities is usually obtained in large quantities by forming a pattern on the surface of the sample with a photoresist and using the mask as a mask to wet-etch the material of the sample, so that the wet etching is a low-cost and simple processing technique.

[0003]

However, since wet etching is an isotropic etching, the mask edge is under-etched, and the so-called side etching amount is large, so that there is a drawback that the processing cannot be performed to the size of the mask. For this reason, conventional wet etching requires several μm
The depth of the pattern is limited to a pattern size of several μm, and the finer processing is performed by a technique using an expensive dry etching apparatus. In addition, in conventional wet etching, in general, when precision processing is performed, the etching rate is extremely reduced, so that the processing time is prolonged, the adhesion between the mask and the sample is deteriorated, the etching failure rate increases, and the cost increases. There was a disadvantage. For this reason, the present invention provides an etching apparatus capable of performing anisotropic etching in wet etching and a method for manufacturing the same, thereby providing a uniform precision part at low cost by processing fine dimensions and mass-producing it. The purpose is.

[0004]

In order to perform anisotropic etching by wet etching, an anisotropic component for vertically cutting the sample surface is required. In order to achieve this object, an etching apparatus based on the present invention basically has a component for ejecting a pressurized chemical solution from a nozzle and applying the same vertically to the sample surface. According to the experiment, the higher the pressure of the vertically ejected chemical, the faster the etching rate to cut the sample material. When the pressure difference from the atmosphere is increased to 1 atmosphere or more, the etching rate is doubled compared to the conventional method of immersing only in the chemical. It turns out that it can be faster than that. It can be inferred that this is because the chemical reaction is promoted by the kinetic energy of the molecules of the chemical solution, and the chemical solution is more easily cut than usual. If the chemical liquid remains in the processing area without being pressed, the side etch will proceed and the anisotropic etching will be disrupted, so a mechanism for scattering the processed chemical liquid from the sample surface with a high-pressure gas or a mechanism for neutralizing the chemical liquid Is an aspect of the present invention. The chemical solution (which may contain carrier gas) ejected from the etching nozzle scatters throughout the sample surface,
In order to remove these, a configuration is adopted in which a drying nozzle for ejecting high-pressure gas is installed. Alternatively, a configuration is provided in which a neutralizing solution is supplied to the sample surface to neutralize the processed chemical solution. The neutralizing solution may be provided on the surface or supplied from a nozzle.

[0005]

FIG. 1 shows an embodiment of a wet etching apparatus according to the present invention as viewed from a side. The sample 1 on which the mask pattern 2 has been formed is fixed to a moving mechanism section 10, and an etching nozzle 4 is arranged to face the sample surface. A high-pressure nitrogen gas 6 and etching chemicals 5 and 5 ′ are jetted from the etching nozzle 4 to process the portion 3 to be etched. The drying nozzle 7 is for spraying and drying the chemical solution remaining on the sample surface, from which high-pressure nitrogen gas for drying 8 is supplied to the sample surface. The ejection port of the etching nozzle 4 has a round or band shape, and the moving mechanism section 10 is swept according to this shape so that uniform etching can be performed over the entire surface of the sample. Since this mechanism only needs to move relatively, the sample may be fixed and the nozzle may be swept. The drying nozzle 7 preferably has a strip-shaped outlet in order not to keep the chemical solution on the entire surface of the sample. FIG. 1 shows an example in which the etching nozzle 4 supplies the high-pressure nitrogen gas 6 and the etching chemicals 5 and 5 ′ individually, but this may be supplied from either, and the nozzle has one port. Then, a pressurized chemical solution or a chemical solution with high-pressure nitrogen gas may be ejected from one place. The high-pressure gas is not limited to nitrogen, and compressed air or the like may be applied according to the application.

[0006] Using the apparatus shown in FIG.
An example of a method for forming an i-part by anisotropic etching will be described below. First, a SiO2 film is formed on the surface of a Si sample, a photoresist layer is applied thereon, and a mask pattern is formed by photolithography. Next, the sample is placed in an etching apparatus and etched. SiO2 film is HF
As a chemical solution of the system, a chemical solution of a KOH aqueous solution is used for Si. The above chemical is spouted vertically from the etching nozzle on the sample surface,
First, the SiO2 film is processed, and then the Si is processed. High-purity high-pressure nitrogen gas is sprayed from the drying nozzle onto the surface so that the scattered chemical solution does not remain on the sample surface. The etching rate increases from 1.5 atm or more of the pressure of the chemical solution, which is suitable for improving the productivity. With this method, the processed shape of Si became the same as that of the mask pattern, and a hole having a substantially vertical cross-sectional shape and a high aspect ratio was obtained.

FIG. 2 shows another embodiment of the main part of the wet etching apparatus according to the present invention as viewed from the side. The sample 21 on which the mask pattern 22 has been formed is fixed to the moving mechanism section 20, and an etching nozzle 24 is arranged so as to face the sample surface. A high-pressure nitrogen gas 26 and etching chemicals 25 and 25 ′ are jetted from the etching nozzle 24,
Thereby, the etched portion 23 is processed. Also,
A neutralizing solution 29 for neutralizing the etching chemical is provided on the surface of the sample, which may be supplied from the neutralizing nozzle to the surface of the sample or may be immersed in the neutralizing solution. The shape of the outlet of the etching nozzle 24 and the mechanism of the moving section are the same as those described in the description of FIG.

An example of a method for forming a Ti micromesh component by anisotropic etching using the apparatus shown in FIG. 2 will be described below. First, a photoresist layer is formed on a sample surface of a Ti plate, and a mask pattern is formed by photolithography. Next, the sample is placed in an etching apparatus and etched. The chemical liquid ejected vertically from the etching nozzle to the sample surface is an aqueous solution of HF, and the pressure is as high as about 3 atm, and processing is performed at high speed. The surface of the sample is covered with a neutralizing solution, and the etching proceeds only in the region ejected from the etching nozzle, and the scattered chemical solution and neutralizing solution are neutralized and no reaction occurs. A vertical hole of 5 μm square was obtained in a Ti plate having a thickness of about 10 μm, and a highly accurate micromesh was easily obtained.

Although the embodiment in which anisotropic etching is performed by wet etching has been described above, the chemical sprayed from the etching nozzle is not limited to a liquid, but a mixture of a liquid and a solid. Note that the liquid may be used. In this case, the solid may be a solid generated by lowering the temperature of the chemical solution or fine particles added to the chemical solution. It is also noted that anisotropic etching can be performed by a device that performs etching by ejecting a chemical solution from an etching nozzle while rotating the sample at a high speed so that no chemical solution remains on the sample surface. In this case, a moving mechanism is added to the etching nozzle for uniform processing. The anisotropic etching according to the present invention has a feature that the structure of the apparatus is simpler than that of the dry etching and can be realized at low cost. Further, since no processing strain remains on the sample, it is particularly effective as a semiconductor device manufacturing apparatus. In the apparatus of the present invention, the active etching solution does not remain on the sample surface, so that the etching mask is less deteriorated. In addition, since a chemical solution having a high etching rate can be used, the processing time can be reduced, and the manufacturing cost of parts can be reduced. is there. It has been expected that parts such as micromachines requiring high precision can be provided at low cost by the apparatus and the manufacturing method of the present invention.

[0010]

According to the present invention, (1) a chemical solution is jetted perpendicularly to the sample surface,
By treating the scattered chemical solution, anisotropic processing can be performed by wet etching, and fine processing can be performed. (2) The apparatus of the present invention can be manufactured at low cost, the manufacturing cost of parts can be reduced by shortening the processing time, and there is a prospect that high precision parts can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a wet etching apparatus according to one embodiment of the present invention.

FIG. 2 is a side view of a main part of a wet etching apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 1, 21: Sample 2, 22: Mask pattern 3, 23: Etched portion 10, 20: Moving mechanism 4, 24: Etching nozzle 5, 5 ', 25, 25': Etching chemical 6, 26: High pressure nitrogen Gas 7: Drying nozzle 8: High-pressure nitrogen gas for drying 29: Neutralizing liquid

Claims (6)

[Claims] 1. An apparatus for wet-etching a sample, comprising a mechanism for jetting a pressurized chemical solution from an etching nozzle to the surface of the sample. 2. The wet etching apparatus according to claim 1, wherein the pressurized chemical solution is formed by jetting a high-pressure gas. 3. The wet etching apparatus according to claim 1, further comprising a mechanism for removing a chemical solution scattered on the surface of the sample after being ejected from the surface of the sample by ejecting a high-pressure gas. 4. The wet etching apparatus according to claim 1, wherein the wet etching apparatus has a mechanism for neutralizing a chemical solution scattered on the sample surface after the ejection with a neutralizing solution. 5. A step of forming a mask pattern on the surface of a sample, a step of installing the sample in the wet etching apparatus according to claim 3, and a step of ejecting a pressurized chemical from an etching nozzle to the surface of the sample, and A step of spraying high-purity high-pressure nitrogen gas from a drying nozzle onto the surface so as not to remain on the surface of the sample. 6. A step of forming a mask pattern on the surface of a sample, a step of installing the sample in the wet etching apparatus according to claim 4, and a step of ejecting a pressurized chemical solution from an etching nozzle to the surface of the sample to remove the scattered chemical solution. A wet etching method characterized by etching the sample surface based on the step of neutralizing the sample surface with a neutralizing solution.