JP2001038698A - Semiconductor micro structure, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form two V-shaped grooves adjacent to each other without increasing the chip size. SOLUTION: In forming two V-shaped grooves in this structural body, one step 22 is formed on one groove forming part of a silicon substrate 20 in advance, and then, an etching protective film 23 is formed on a surface of the silicon substrate. After this etching protective film 23 is formed, a resist mask 24 for regulating a groove area is formed on the surface of the etching protective film 23 outside the area on which two V-shaped grooves are formed. After the resist mask 24 is formed, a part of the etching protective film 23 is etched by an RIE device, and the resist mask 24 for regulating an unnecessary groove area. The etching protective film which is not etched but remaining on a side wall part of the step 22 forms an etching protective film 23' for separation. The anisotropic etching is implemented with an etching solution such as potassium hydroxide aqueous solution to form a V-shaped groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor microstructure constituting a flow sensor, a microactuator, a microvalve, a micropump and the like used for home electric appliances and medical products, and a method for producing the same.

[0002]

2. Description of the Related Art A conventional method for manufacturing a semiconductor microstructure will be described with reference to FIG.

FIG. 2 shows a process of forming V-shaped grooves 11 and 12 on the surface of a silicon substrate 1 by wet anisotropic etching so as to be adjacent to each other. As shown in FIG. 2B is formed by forming an etching protection film 2 on the surface of the substrate 1 other than the groove forming portion, forming a separation etching protection film 3 at a boundary portion of the groove to be formed, and performing wet anisotropic etching. The V-shaped grooves 11 and 12 are formed as shown in FIG.

[0004]

However, according to the above-described method, since it is necessary to form the etching protection film for isolation 3, the area of this portion has limited the miniaturization of the chip.

On the other hand, if the width of the separation etching protective film 3 is too small, a deep groove may be formed by etching for a long time, and the side walls 13 of the V-shaped grooves 11 and 12 may be formed.
As a result, there is a possibility that a portion under the etching protection film for separation 3, that is, the upper end of the separation wall 14 is separated from the back surface of the etching protection film for separation 3 and penetrates as shown in FIG.

That is, the orientation of the main surface of the silicon substrate 1 is <10
0> When the crystal plane is used, the side walls 1 of the V-shaped grooves 11 and 12
The plane No. 3 becomes a <111> crystal plane and is not etched by short-time etching, but is slightly etched by long-time etching and recedes from the original position shown by the broken line in FIG. That's what happens.

The present invention has been made in view of the above points, and has as its object to provide a semiconductor microstructure capable of forming two adjacent V-shaped grooves without increasing the chip size. It is an object of the present invention to provide a body and a method for producing the same.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a part of a sloped side wall surface of a V-shaped groove formed on the surface of a semiconductor substrate is protected by etching when the groove is formed. It is characterized by comprising a film.

According to the second aspect of the present invention, at least two adjacent V-shaped grooves are formed on the same plane of the semiconductor substrate by etching a part of the semiconductor substrate, and a separation wall for separating both grooves is formed. It is characterized in that the upper surface is a ridge line composed of the upper edge of the inclined side wall surface adjacent to both grooves.

According to the third aspect of the present invention, after forming a recess in which the side wall surface is inclined in advance in the groove forming region of the semiconductor substrate and forming an etching protection film for forming a groove on a part of the side wall surface in which the recess is inclined, The method is characterized in that a groove is formed at a groove forming portion of a semiconductor substrate by wet anisotropic etching.

According to a fourth aspect of the present invention, in the third aspect of the present invention, at least one of the two adjacent groove forming regions of the semiconductor substrate is formed with a concave portion having a sidewall surface inclined in advance, and the other portion than the groove forming region is formed. After an etching protection film is formed on a part of the side wall surface to be inclined, grooves are respectively formed in two adjacent groove forming regions of the semiconductor substrate by wet anisotropic etching.

According to a fifth aspect of the present invention, in the third aspect of the present invention, a concave portion is formed in at least one of two adjacent groove forming regions of the semiconductor substrate, and after the formation, the entire surface of the semiconductor substrate including the concave portion is etched. A protective film is formed, and after the formation, after removing the etching protective film in a region other than the inclined side wall surface of the recess and covering the other groove forming region, two adjacent two of the semiconductor substrate are subjected to wet anisotropic etching. A groove is formed in each of the groove forming regions.

According to a sixth aspect of the present invention, in any one of the third to fifth aspects of the present invention, the etching protection film is etched by reactive ion etching. A method for manufacturing a microstructure.

According to a seventh aspect of the present invention, in any one of the third to fifth aspects, the etching protection film is a silicon oxide film.

According to an eighth aspect of the present invention, in any one of the third to fifth aspects, the etching protection film is a silicon nitride film.

According to a ninth aspect of the present invention, in any one of the third to fifth aspects of the present invention, the etchant used for the wet anisotropic etching is an aqueous potassium hydroxide solution.

According to a tenth aspect of the present invention, in any one of the third to fifth aspects of the present invention, the etchant used for wet anisotropic etching is a solution that does not corrode anilluminium.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. (Embodiment 1) FIG. 1 shows a manufacturing process of this embodiment. In the manufacturing process of this embodiment, when forming two V-shaped grooves, first, as shown in FIG. An etching protection film 21 made of a silicon oxide film is formed on both sides of the 20 <100> crystal plane except for a region where one V-shaped groove is to be formed. In FIG. 1A, the etching protection film 21 on the side opposite to the grooved surface is omitted, but the etching protection film 21 is actually formed on the surface. The same applies to the following drawings.

After the formation of the etching protection film 21, a window is formed on a part of the etching protection film 21 by a photolithography process and an etching process.

Next, anisotropic etching is performed using an etching solution, for example, an aqueous solution of potassium hydroxide (KOH), and a concave portion (hereinafter referred to as a step) 22 having a trapezoidal cross section in the width direction as shown in FIG. Is formed in the above-mentioned groove forming portion. Both side walls of the step 22 have a tilt in the <111> crystal plane direction.

After the step 22 is formed, the etching protection film 21 is removed by etching, and after this removal, the etching protection film 23 made of a silicon oxide film is again oxidized by oxidation as shown in FIG.
Silicon substrate 2 including step 22 as shown in FIG.
0 is formed on the surface.

After the formation of the etching protection film 23, FIG.
As shown in (d), a resist mask 24 for defining a groove region is formed on the surface of the etching protection film 23 outside the region where two V-shaped grooves are to be formed by a photolithography process.

After this formation, a part of the etching protection film 23 is etched by an RIE (reactive ion etching) device. This processing may use an ion milling device or the like. At this time, the etching protection film on the side wall of the step 22 is not etched by the etching directivity of the RIE apparatus in a direction orthogonal to the surface of the silicon substrate 20 and remains. After that, when the unnecessary groove region defining resist mask 24 is removed, it becomes as shown in FIG. Here, the etching protection film remaining without being etched on the side wall of the step 22 constitutes the separation etching protection film 23 '.

Thereafter, anisotropic etching is performed with an etching solution such as an aqueous solution of potassium hydroxide (KOH) to form a V-shaped groove 25 having a desired depth with both side walls inclined in the <111> crystal plane direction. , 26 are formed as shown in FIG. 1 (f) to obtain a desired semiconductor microstructure.

(Embodiment 2) Although a silicon oxide film is used in Embodiment 1 as the etching protection film 23 formed in FIG. 1C, in this embodiment, the etching protection film 23 is formed with an etching solution such as potassium hydroxide (KOH). The etching protection film 23 is formed of a silicon nitride film which is difficult to be etched, and a deep groove can be formed.

(Embodiment 3) As an etching solution used in FIG. 1 (f), an aqueous solution of potassium hydroxide is used in Embodiment 1, but in this embodiment, TMAH (tetramethylammonium hydroxide) which does not corrode aluminum is used. The liquid was used. By using this TMAH solution, it becomes possible to form the etching protection film 23 from aluminum in FIG. 1C, and the process can be simplified.

[0027]

According to the first aspect of the present invention, since an etching protection film is provided on a part of the inclined side wall surface of the V-shaped groove formed on the surface of the semiconductor substrate when the groove is formed, the chip size can be increased. It is possible to provide a microstructure having a groove with high accuracy without accuracy.

According to a second aspect of the present invention, at least two adjacent V-shaped grooves are formed on the same plane of the semiconductor substrate by etching a part of the semiconductor substrate, and a separation wall for separating both grooves is formed. Since the upper surface is a ridge line composed of the upper edge of the side wall surface adjacent to the two grooves, the micro groove having at least two V-shaped grooves without increasing the chip size by minimizing the distance between the adjacent grooves. A structure can be provided.

According to a third aspect of the present invention, after forming a concave portion having a sloped side wall surface in advance in a groove forming region of a semiconductor substrate and forming an etching protective film for forming a groove on a part of the side wall surface where the concave portion is slanted, Since the groove is formed in the groove forming portion of the semiconductor substrate by wet anisotropic etching, retreat of the side wall of the groove due to re-etching during long-time etching can be prevented, and as a result, the groove can be formed with high accuracy.

According to a fourth aspect of the present invention, in the third aspect of the invention, at least one of two adjacent groove forming regions of the semiconductor substrate is formed with a concave portion having a sloped side wall surface in advance, and a concave portion other than the groove forming region is formed. After forming an etching protection film on a part of the inclined side wall surface, grooves are respectively formed in two adjacent groove forming regions of the semiconductor substrate by wet anisotropic etching. Since the adjacent grooves are separated, two adjacent grooves can be formed without depending on the dimensions of the etching protection film, so that there is an effect that the chip size can be reduced.

According to a fifth aspect of the present invention, in the third aspect of the present invention, a concave portion is formed in at least one of two adjacent groove forming regions of the semiconductor substrate, and after the formation, the entire surface of the semiconductor substrate including the concave portion is etched. Forming a protective film, after the formation,
The grooves are formed in two adjacent groove forming regions of the semiconductor substrate by wet anisotropic etching after removing the etching protection film in a region other than the inclined side wall surface of the recess and covering the other groove forming region. The third and fourth aspects of the present invention have the effect.

According to a sixth aspect of the present invention, in any one of the third to fifth aspects of the present invention, the etching protection film is etched by reactive ion etching. Thus, the etching protection film can be etched without the need, and the effects of the third and fourth aspects of the present invention are obtained.

According to a seventh aspect of the present invention, in any one of the third to fifth aspects of the present invention, since the etching protection film is a silicon oxide film, it is possible to perform wet anisotropic etching for a long time and to form a deep groove. There is an effect that it becomes possible.

According to an eighth aspect of the present invention, since the etching protection film is a silicon nitride film in any one of the third to fifth aspects, an effect that a deeper groove can be formed than in the case of the seventh aspect of the invention can be obtained. There is.

According to a ninth aspect of the present invention, in any one of the third to fifth aspects of the present invention, the etching solution used for the wet anisotropic etching is an aqueous solution of potassium hydroxide. There is an effect that it is possible to prevent the side wall from retreating and to form a highly accurate groove.

According to a tenth aspect of the present invention, in any one of the third to fifth aspects of the present invention, since the etching solution used for wet anisotropic etching is a solution that does not corrode anilluminium, the etching protection curtain can be formed of aluminum. Therefore, there is an effect that the process can be simplified.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 20 silicon substrate 21 etching protection film 22 step 23 etching protection film 23 'separation etching protection film 24, 25 V-shaped groove

Claims (10)

[Claims] 1. A semiconductor microstructure comprising: a V-shaped groove formed on a surface of a semiconductor substrate; 2. An etching process for a part of a semiconductor substrate to form at least two adjacent V-shaped grooves on the same plane of the semiconductor substrate, and to form an upper surface of a separation wall separating the two grooves from each other. A semiconductor microstructure characterized by a ridge line comprising an upper edge of an adjacent inclined side wall surface. 3. A method according to claim 1, further comprising: forming a concave portion having an inclined side wall surface in advance in the groove forming region of the semiconductor substrate; forming an etching protective film for forming a groove on a part of the inclined side wall surface of the concave portion; Forming a groove in a groove forming portion of a semiconductor substrate by using the method. 4. A recess having an inclined sidewall in advance in at least one of two adjacent trench forming regions of a semiconductor substrate, and an etching protection film is formed on portions other than the trench forming region and on a portion of the sidewall where the recess is inclined. 4. The method of manufacturing a semiconductor microstructure according to claim 3, wherein after the formation, grooves are respectively formed in two adjacent groove forming regions of the semiconductor substrate by wet anisotropic etching. 5. A concave portion is formed in at least one of two adjacent groove forming regions of the semiconductor substrate, and after the formation, an etching protection film is formed on the entire surface of the semiconductor substrate including the concave portion. After removing the etching protection film in a region other than the inclined side wall surface and covering the other groove forming region, grooves are formed in two adjacent groove forming regions of the semiconductor substrate by wet anisotropic etching. The method for manufacturing a semiconductor microstructure according to claim 3, wherein 6. The method of manufacturing a semiconductor microstructure according to claim 3, wherein the etching protection film is etched by reactive ion etching. 7. The method according to claim 3, wherein the etching protection film is a silicon oxide film. 8. The method according to claim 3, wherein the etching protection film is a silicon nitride film. 9. The method of manufacturing a semiconductor microstructure according to claim 3, wherein an etching solution used for wet anisotropic etching is an aqueous solution of potassium hydroxide. 10. The method for manufacturing a semiconductor microstructure according to claim 3, wherein an etching solution used for wet anisotropic etching does not corrode anilluminium.