JP3430827B2 - Method for manufacturing semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a concave portion in a substrate, forms a light reflecting surface on the side surface of the concave portion, reflects light emitted from a light emitting element arranged in the concave portion on the side surface, and reflects the light above the substrate. The present invention relates to a semiconductor device manufacturing method for producing a semiconductor device to be taken out. More specifically, the present invention relates to a method of manufacturing a semiconductor device, which is devised so as to easily form a light reflecting surface that forms an angle of 45 ° with respect to the substrate surface.

[0002]

2. Description of the Related Art As an optical disk reading apparatus, there is an apparatus that takes out the light emitted from a light emitting element, applies it to the optical disk, detects the light reflected by the optical disk with a light receiving element, and reads the information on the optical disk. FIG. 7 is a diagram showing a configuration example of a semiconductor device used in such a reading device. In FIG. 7, 1 is a silicon substrate, 2 is a concave portion formed in the silicon substrate 1, and 3 is a reflecting surface formed on the substrate surface and the side surface of the concave portion 2. The reflecting surface 3 is an inclined surface that makes a predetermined angle with the substrate surface. Reference numeral 4 denotes a light emitting element, which is arranged in the recess 2 and irradiates the reflecting surface 3 with light. This irradiation light is reflected by the reflecting surface 3, is extracted above the substrate as shown by A, and strikes the optical disc.

FIG. 8 is a configuration diagram of a recess formed by a conventional manufacturing method. This recess is created by the following procedure. The substrate surface of the silicon substrate 1 is the (100) surface. This (100) plane is anisotropically etched with a potassium hydroxide-based aqueous solution to form a truncated pyramid-shaped recess 2. The etching location is selected with a mask. At this time, the slope serving as the reflecting surface 3 is the (111) plane, and the angle formed with the substrate surface is about 54 °. Therefore, when the light emitting element emits light toward the substrate surface, the light reflected by the reflecting surface 3 does not proceed in the direction orthogonal to the substrate surface. In order to extract light in the direction orthogonal to the substrate surface, the reflecting surface 3 forming an angle of 45 ° with the substrate surface must be formed. In order to form a reflecting surface forming an angle of 45 ° with the surface of the substrate, conventionally, as shown in FIG. 9, when the silicon member 5 is sliced to form a wafer, the silicon member 5
By tilting the slice plane by 9 ° with respect to the (100) plane (the tilt angle is referred to as an off-angle) and setting the substrate surface in the direction indicated by the broken line in FIG. I was getting a face.

However, a silicon substrate having a large off-angle is expensive due to its peculiarity, and when an epitaxial layer is formed to form a transistor element or the like, the quality of the epitaxial layer deteriorates and the pattern shifts. However, there is a problem that pattern distortion is likely to occur.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a isopropyl alcohol is added to potassium hydroxide to a silicon substrate having a (100) face as a substrate face. solution or by performing anisotropic etching with ethylene diamine, pyrocatechol, the reflective surface forming an angle of the substrate surface and the 45 ° be a silicon substrate having no off-angle d
It is an object of the present invention to realize a method for manufacturing a semiconductor device that can be easily formed by etching.

[0006]

The present invention is a method of manufacturing a semiconductor device having the following structure. (1) A recess is formed in a substrate, a light reflecting surface is formed on a side surface of the recess, and a semiconductor device is produced in which light emitted from a light emitting element arranged in the recess is reflected by the side surface and is extracted above the substrate. In a method of manufacturing a semiconductor device, <100
＞ direction as orientation flat direction (10
Anisotropic etching is performed with a solution of potassium hydroxide and isopropyl alcohol on a silicon substrate having no off-angle with the ( 0) plane as the substrate surface, and an angle of 45 ° is formed with respect to the substrate surface ( 110) A method for manufacturing a semiconductor device, characterized in that a concave portion whose side surface is exposed is formed. (2) A recess is formed in a substrate, a light reflecting surface is formed on a side surface of the recess, and a semiconductor device is produced in which light emitted from a light emitting element arranged in the recess is reflected by the side surface and is extracted above the substrate. In a method of manufacturing a semiconductor device, <110
＞ direction as orientation flat direction (10
Anisotropic etching is performed with a solution of potassium hydroxide and isopropyl alcohol on a silicon substrate having no off-angle with the ( 0) plane as the substrate surface, and an angle of 45 ° is formed with respect to the substrate surface ( 110) A method for manufacturing a semiconductor device, characterized in that a concave portion whose side surface is exposed is formed. (3) The method for producing a semiconductor device according to (1) or (2), wherein the anisotropic etching is performed using ethylene diamine pyrocatechol.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of an embodiment of the present invention. Figure 1
Here, 10 is a wafer whose (100) plane is the wafer surface and whose <100> direction is the orientation flat.
101 is an orientation flat surface. Cover the wafer 10 with a mask to select etching locations,
When anisotropic etching is performed with a solution of isopropyl alcohol added to potassium hydroxide, a truncated pyramid-shaped recess 11 is formed at the etched portion. At this time, the (110) plane forming an angle of 45 ° with the substrate surface is exposed on the side surface of the recess 11. This surface is used as a light reflecting surface. Note that ethylene / diamine / pyrocatechol may be used as the etching liquid.

FIG. 2 is a vertical sectional view of the recess 11. Figure 2
Reference numeral 12 is a mask for selecting an etching location. The side surface of the recess 11 forms an angle of 45 ° with the substrate surface (11
0) surface is exposed. Thus, even if the substrate does not have an off-angle, an inclined surface forming an angle of 45 ° with the substrate surface can be formed on the side surface of the recess.

A procedure for manufacturing a semiconductor device by the method according to the present invention will be described. A light receiving element such as a photodiode and a circuit element such as a transistor are formed on a silicon substrate having an orientation flat in the <100> direction and having a (100) plane as a substrate surface. FIG. 3 is a diagram showing an example of the produced semiconductor device. In FIG. 3, 13 is a transistor, E is an emitter, C is a collector, and B is a base. 14 is a photodiode, A is an anode,
K is a cathode. n and p are conductivity types. afterwards,
The surface of the substrate is protected by an oxide film, the micromirror is patterned in the <100> direction, which is the same direction as the orientation flat direction, and anisotropic etching is performed using a solution of potassium hydroxide and isopropyl alcohol. Form a mirror. For patterning of the micromirror, a patterning portion is selected using a mask.
Furthermore, wiring is performed and the laser diode is bonded to the recess. FIG. 4 is a diagram showing an example of the produced semiconductor device. In FIG. 4, reference numeral 15 is a laser diode arranged in the concave portion 11, and 16 is a micromirror portion formed on the side surface of the concave portion 11. The micro-mirror unit 16 and the substrate surface 4
It is formed on the (110) plane forming an angle of 5 °.

FIG. 5 is an operation explanatory diagram of the semiconductor device of FIG. The light emitted from the laser diode 15 is reflected by the micro mirror portion 16 forming an angle of 45 ° with the substrate surface,
It hits the optical disc 17 above the micromirror unit 16. The light reflected by the optical disk 17 enters the photodiode 14 and is converted into an electric current there. A signal processing circuit including the transistor 13 and the like performs signal processing based on this current. As a result, the information on the optical disc 17 is read. The emitted light from the laser diode 15 may be detected by the monitor photodiode after being reflected by the micromirror unit 16. Thereby, the emitted light of the laser diode 15 can be monitored. The micro mirror unit 1
If a monitor photodiode is formed at 6, the light emitted from the laser diode 15 can be directly monitored.

FIG. 6 is an explanatory view of another embodiment of the present invention. Reference numeral 20 is a wafer having a (100) plane as a wafer plane and a <110> direction as an orientation flat.
201 is an orientation flat surface. When the wafer 20 is also etched in the same manner as the wafer 10, a concave portion 21 is formed in which a slope forming an angle of 45 ° with the substrate surface is exposed.

A normal wafer is a wafer having an orientation flat in the <110> direction. When a normal wafer is anisotropically etched using a solution of isopropyl alcohol in potassium hydroxide or ethylene diamine pyrocatechol, the recesses formed by etching are aligned with the orientation flat direction by 45 °.
They are arranged in a direction forming an angle of °. Therefore, the photolithography work is difficult. On the other hand, the wafer in the embodiment of FIG. 1 is a special wafer having the orientation flat in the <100> direction. For this wafer,
When anisotropic etching is performed using a solution obtained by adding isopropyl alcohol to potassium hydroxide or ethylene / diamine / pyrocatechol, the recesses formed by the etching are arranged in the same direction as the orientation flat direction. Therefore, photolithography work is easy to perform. When anisotropic etching is performed using a solution obtained by adding isopropyl alcohol to potassium hydroxide or ethylene / diamine / pyrocatechol, the magnitude relationship between the etching rates on the respective surfaces is as follows. (111) <(100) <(110)

[0013]

According to the present invention, a silicon substrate having a (100) plane as a substrate surface is anisotropically etched using a solution of potassium hydroxide with isopropyl alcohol or ethylene diamine pyrocatechol. By performing the above, the inclined surface forming an angle of 45 ° with the substrate surface is exposed on the side surface of the recess. Therefore, even if a silicon substrate having no off-angle is used, the reflecting surface forming an angle of 45 ° with the substrate surface can be easily formed by etching .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a semiconductor device manufactured by the method according to the present invention.

FIG. 4 is a diagram showing an example of a semiconductor device manufactured by the method according to the present invention.

5 is an operation explanatory diagram of the semiconductor device of FIG. 4;

FIG. 6 is an explanatory diagram of another embodiment of the present invention.

FIG. 7 is a diagram showing a configuration example of a semiconductor device used in an optical disc reader.

FIG. 8 is an explanatory diagram of a conventional semiconductor device manufacturing method.

FIG. 9 is an explanatory diagram of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 31/12 H01S 5/00-5/50

Claims (3)

(57) [Claims] 1. A semiconductor device in which a concave portion is formed on a substrate, a light reflecting surface is formed on a side surface of the concave portion, and light emitted from a light emitting element arranged in the concave portion is reflected on the side surface and is taken out above the substrate. In the method of manufacturing a semiconductor device to be prepared, potassium hydroxide, isopropyl alcohol are used for a silicon substrate having no orientation, the <100> direction being the orientation flat direction and the (100) face being the substrate surface. A method of manufacturing a semiconductor device, characterized in that anisotropic etching is performed with a solution added with to form a concave portion whose side surface is exposed to a (110) plane forming an angle of 45 ° with respect to the substrate surface. 2. A semiconductor device in which a concave portion is formed on a substrate, a light reflecting surface is formed on a side surface of the concave portion, and light emitted from a light emitting element arranged in the concave portion is reflected on the side surface and is extracted above the substrate. In the method of manufacturing a semiconductor device to be prepared, potassium hydroxide, isopropyl alcohol and potassium hydroxide are added to a silicon substrate having an orientation flat direction in the <110> direction and a substrate surface in the (100) plane and having no off-angle. A method of manufacturing a semiconductor device, characterized in that anisotropic etching is performed with a solution added with to form a concave portion whose side surface is exposed to a (110) plane forming an angle of 45 ° with respect to the substrate surface. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the anisotropic etching is performed using ethylene diamine pyrocatechol.