WO2003077306A1

WO2003077306A1 - Semiconductor device and its manufacturing method

Info

Publication number: WO2003077306A1
Application number: PCT/JP2003/002787
Authority: WO
Inventors: Hideyuki Andou
Original assignee: Sankan Electric Co., Ltd.
Priority date: 2002-03-08
Filing date: 2003-03-10
Publication date: 2003-09-18
Also published as: TW200415796A; TWI241028B; JPWO2003077306A1

Abstract

A mesa diode (1) comprises a semiconductor substrate (2), a protection film (3), a cathode electrode (4), and an anode electrode (5). A mesa groove (9) is formed in one main face of the semiconductor substrate (2) by etching using a metal film constituting the cathode electrode (4) as a mask. The mesa groove (9) is annularly formed along the edge of the semiconductor substrate (2). The protection film (3) is constituted of a fluid polyimide resin volatilizing at a temperature lower than the melting point of the material constituting the cathode electrode (4), cures, and coats the bottom and side of the mesa groove (9). The cathode electrode (4) is formed on one main face of the semiconductor substrate (2). The anode electrode (5) is formed on the other main face of the semiconductor substrate (2).

Description

TECHNICAL FIELD The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly, to a semiconductor device having a mesa groove and a method for manufacturing the same. Background art

It is known to form an annular inclined groove (mesa groove) along the outer peripheral surface of a semiconductor substrate to partition the semiconductor element and to make the semiconductor element have a relatively high breakdown voltage. As a semiconductor element manufactured by such a method, for example, a mesa diode (a mesa diode) is cited. Figure 4 shows a cross section of a general mesa diode.

As shown in the figure, the mesa diode 51 includes a semiconductor substrate 52, a force source electrode 53 formed on one main surface (upper surface) of the semiconductor substrate 52, and the other main surface (lower surface) of the semiconductor substrate. ) Formed on the anode electrode 54. The semiconductor substrate 52 includes a P + -type semiconductor region 55 forming an anode region, and an n-type semiconductor region 56 and an n ⁺ -type semiconductor region 57 forming a force source region. A mesa groove 58 is formed on the upper surface of the semiconductor substrate 52 so that the p + type semiconductor region 55, the n − type semiconductor region 56, the n + type semiconductor region 57, and the pn junction are exposed. You. A protective film 59 made of glass or the like is formed on the surface of the mesa groove 58, and the semiconductor regions 55 to 57 exposed by the mesa groove 58 are covered with the protective film 59.

Conventionally, a mesa diode having such a configuration has been manufactured by, for example, a procedure described below.

First, the upper surface of the semiconductor substrate (semiconductor wafer) 52 on which the p ⁺ type semiconductor region 55, the n ⁻ type semiconductor region 56 and the n ⁺ type semiconductor region 57 are formed is etched to have a U-shaped cross section. A mesa groove 58 is formed. Next, after applying glass to the entire upper surface of the semiconductor wafer 52 including the mesa groove 58, the applied glass is fired. This allows the glass film Is formed, and the upper surface of the semiconductor wafer 52 is covered with the formed glass film.

Subsequently, the glass film on the η ⁺ type semiconductor region 57 in the region where the force source electrode 53 is to be formed is removed by etching to form a protective film 59 covering the surface of the mesa groove 58. Next, for example, an aluminum film is formed by vacuum evaporation or the like on the portion where the glass film has been removed by etching. The surface of the aluminum film is etched to form a force source electrode 53 from the aluminum film. Further, on the lower surface of the semiconductor wafer 52, for example, titanium, nickel, palladium and silver are sequentially vacuum-deposited to form an anode electrode 54. Then, the semiconductor wafer 52 is diced along the mesa groove 58.

The protective film 59 covering the mesa groove 58 is liable to cause insulation rupture if the electrical and physical properties are not stable. For this reason, in the conventional manufacturing process, the glass applied to the mesa 58 is fired at, for example, about 700 ° C. to reduce the possibility of insulation rupture of the protective film 59, and the glass film (the protective film 5 9) to stabilize the characteristics of the protective film 59.

At such a temperature, the material (for example, aluminum) constituting the force source electrode 53 may be deteriorated by heat. The temperature at which the material of the force sword electrode 53 deteriorates is, for example, the melting point of the material. Since the melting point of the aluminum film constituting the power source electrode 53 is about 600 ° C., after forming an aluminum film on one main surface of the semiconductor substrate 52, the protective film 59 is formed by firing. When this is generated, the aluminum film is heated at a temperature higher than the melting point. At temperatures above the melting point, the aluminum film is susceptible to substantial damage. Therefore, in the conventional manufacturing process, a protective film 59 for covering the mesa groove 9 is formed first, and then a force source electrode 53 is formed in order to make the aluminum film hard to substantially damage.

However, in the manufacturing method of such a procedure, a plurality of etching steps are required when forming the protective film 59 and the cathode electrode 53, so that the manufacturing process is relatively complicated. It was also difficult to reduce costs.

Also, since the protective film 59 is formed on the entire upper surface of the semiconductor wafer 52 including the mesa groove 58, the protective film 59 in the area where the force electrode 53 is to be formed is etched. In some cases, the protective film 59 may remain on the edge of the region where the force source electrode 53 is to be formed. If the aluminum film forming the power source electrode 53 is formed on the area where the power source electrode 53 is to be formed while the protective film 59 remains, the aluminum film on the remaining protective film 59 protrudes. . In this case, the projection of the aluminum film hinders the etching of the surface of the aluminum film. Also, it is difficult to etch the protruding portion of the aluminum film so that the edge of the aluminum film and the edge of the mesa groove 58 are aligned in a cross section. For this reason, it was difficult to perform etching with high accuracy.

Therefore, high productivity of the mesa diode cannot be obtained by the conventional manufacturing method.

On the other hand, if an aluminum film is first formed on the semiconductor substrate 2 and then a protective film is formed, glass is baked at a temperature lower than the temperature at which the aluminum film deteriorates so as not to damage the aluminum film. 9 must be generated. Therefore, a protective film 59 having stable characteristics cannot be obtained.

The present invention has been made in view of the above problems, and has as its object to provide a semiconductor element capable of improving productivity and a method for manufacturing the same. Disclosure of the invention

In order to achieve the above object, a method for manufacturing a semiconductor device according to a first aspect of the present invention includes a semiconductor substrate (2) and a semiconductor substrate (2) formed in a predetermined region on one main surface of the semiconductor substrate (2). An electrode (4), a mesa groove (9) formed on the semiconductive substrate (2) along the outer periphery of one main surface of the semiconductor substrate (2), and an inner surface of the mesa groove (9). In a method of manufacturing a mesa-shaped semiconductor element (1) having a protective film (.3) to cover, a metal film forming the electrode is formed in a predetermined region on one main surface of the semiconductor substrate (2). (11) is formed, and using the metal film (11) as a mask, the mesa groove (9) is formed along an outer periphery of a negative main surface of the semiconductor substrate (2), and the metal film ( 11. Cover the inner surface of the mesa groove (9) with a material that is cured by heat at a temperature lower than the temperature at which Forming the protective film (3), and dicing the semiconductor substrate (2) along the mesa groove (9) ′ covered with the protective film (3). It is characterized by. According to this configuration, after a metal film forming an electrode is formed in a predetermined region on one main surface of the semiconductor substrate, a groove is formed on one main surface of the semiconductor substrate, and the metal film is heated by heat. Thus, a protective film covering the inner surface of the groove is formed from a material that cures at a temperature lower than the temperature at which substantial damage is caused. Therefore, it is not necessary to repeat the etching process a plurality of times to form the protective film and the metal film. Therefore, the manufacturing process of the semiconductor device can be simplified, and the productivity of the semiconductor device can be improved. Further, since the protective film is formed using a material that is cured by heat at a temperature lower than the temperature at which the metal film deteriorates, the formation of the protective film does not substantially damage the metal film.

In the above manufacturing method, the electrode (4) is formed using aluminum, and the electrode (4) is formed using a material that is cured by heat at a temperature of 100 ° C. to 400 ° C. lower than the melting point of aluminum-palladium. A protective film (3) may be formed.

In the above manufacturing method, in order to solve the above problem so as to form the protective film (3) from a polyimide resin, a semiconductor element according to a second aspect of the present invention includes a semiconductor substrate (2), A first electrode (4) formed on a predetermined area on one main surface of the semiconductor substrate (2), and a second electrode (5) formed on the other main surface of the semiconductor substrate (2). A mesa groove (9) formed in the semiconductor substrate (2) along an outer periphery of one main surface of the semiconductor substrate (2); and a protective film (3) covering an inner surface of the mesa groove (9). In the mesa-type semiconductor device (1) having the following, the first electrode (4) is composed of a metal film (1 1), and the protective film (3) is composed of the metal film (1 1). It is characterized by comprising a material that is cured by heat at a temperature lower than the temperature at which it deteriorates.

According to this configuration, since the protective film is made of a material that is cured by heat at a temperature lower than the temperature at which the metal film deteriorates, substantial damage to the electrodes is caused when the protective film is formed. Will not give. For this reason, the protective film can be formed after the electrode is formed, and it is not necessary to repeat a plurality of etching steps to form the protective film and the electrode. Therefore, the manufacturing process of the semiconductor device can be simplified, and the productivity of the semiconductor device can be improved. The mesa groove (9) is formed by etching one main surface of the semiconductor substrate (2) using the metal film (11) constituting the first electrode (4) as a mask. It may be formed.

The semiconductor substrate (2) has a second conductivity type second semiconductor region in which an interface between a first conductivity type first semiconductor region (6) and the first five semiconductor region (6) forms a pn junction. (7) and a third conductive type third semiconductor region (8) in contact with the second semiconductor region (7) and having a higher concentration than the second semiconductor region (7). The protective film (3) may be made of a material which is cured by heat at a temperature lower by 1100 ° C. to 400 ° C. than a melting point of the metal film constituting the first electrode (4). The first electrode (4) may be made of aluminum, and the protective film (3) may be made of a material which is cured by heat at 200 to 500 ° C.

15 The protective film (3) may be made of polyimide resin. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing a configuration of a mesa-type diode according to an embodiment of the present invention.

2 (a) to 2 (g) are cross-sectional views for explaining a manufacturing process of the mesa diode according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a modification of the semiconductor device according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a conventional mesa diode.

twenty five

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a semiconductor device and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the drawings using a mesa-type diode as an example.

As shown in cross section in FIG. 1, the mesa diode 1 has a semiconductor substrate 2 and a protective film 3 , A power source electrode 4 and an anode electrode 5.

The semiconductor substrate 2 includes a first semiconductor region 6, a second semiconductor region 7, and a third semiconductor region 8. A portion of the semiconductor substrate 2 excluding the second semiconductor region 7 and the third semiconductor region 8 constitutes a first semiconductor region 6.

The first semiconductor region 6 is formed of a semiconductor region of a first conductivity type, for example, ap ⁺ type, and functions as a cathode region. The first semiconductor region 6 has 30 μη! The thickness is about 300 μm. The first semiconductor region 6 is formed on the impurity concentration of about 1 X 1 0 ¹⁶ cm one ^{^{3 ~ 1 X 1 0 21 cm-}} 3.

The second semiconductor region 7 is formed on one main surface of the first semiconductor region 6. The second semiconductor region 7 is composed of a semiconductor region of the second conductivity type, for example, n-type. The second semiconductor region 7 is formed with a thickness of about 10 / Xm to 200 m. The second semiconductor region 7 is formed with an impurity concentration of about 1 × 10 ¹² cm— ³ to 1 × 10 ¹⁸ cm— ³ . Therefore, the semiconductor substrate 2 has a pn junction formed at the interface between the second semiconductor region 7 and the first semiconductor region 6.

The third semiconductor region 8 is formed on the upper surface of the second semiconductor region 7. The third semiconductor region 8 is formed of an n + -type semiconductor region having an n-type impurity concentration higher than that of the second semiconductor region 7, and functions as an anode region. The third semiconductor region 8 is formed to a thickness of about 50 μηι to 300 / m. The third semiconductor region 8 is formed on the impurity concentration of about l X 1 0 ¹⁷ cm one ^{^{3 ~ 1 X 1 0 22 cm-}} 3. '

On the upper surface of the semiconductor substrate 2, an inclined groove (mesa groove) 9 is formed. The mesa groove 9 is formed in an annular shape along the outer peripheral edge of the semiconductor substrate 2. The mesa groove 9 has a depth such that the first semiconductor region 6 is exposed at the bottom surface. Therefore, the third semiconductor region 8, the second semiconductor region 7, and the first semiconductor region 6 are exposed from the side and bottom surfaces of the mesa groove 9, and the pn junction between the first semiconductor region 6 and the second semiconductor region 7 is further increased. The edge is exposed. The mesa groove 9 is formed in a shape inclined from the upper surface of the semiconductor substrate 2 toward the lower surface (other surface), for example, so that the upper surface side of the semiconductor substrate 2 has a reduced diameter (a divergent shape). Therefore, the mesa diode 1 has a substantially trapezoidal shape as shown in FIG.

The protective film 3 includes the first semiconductor region 6, the second semiconductor region 7, ぴ Formed on the side and bottom surfaces of the mesa groove 9 so as to cover the third semiconductor region 8.

The protective film 3 is made of a material that cures at a lower temperature than the material constituting the cathode electrode 4 is deteriorated by heat. The temperature at which the material of the cathode electrode 4 deteriorates is, for example, the melting point of the material. Therefore, it is preferable that the protective film 3 be made of a material that is cured by heat at a temperature lower by 100 ° C. to 400 ° C. than the melting point of the material forming the force source electrode 4. For example, suppose that force source electrode 4 is made of aluminum. In this case, the protective film 3 may be made of a polyimide resin. The polyimide resin undergoes heat treatment at a temperature lower than the melting point of aluminum (about 600 ° C) (about 200 ° C to 500 ° C), and the solvent contained in the resin volatilizes and shrinks. Can be heat cured. Further, the polyimide resin can form a relatively hard and dense resin film by thermosetting at a temperature of 200 ° C. to 50 ° C. Therefore, when the polyimide resin is used as the material of the protective film 3, the aluminum film forming the cathode electrode 4 is not substantially damaged by heat. For this reason, in the present embodiment, a polyimide resin is used as the material of the protective film 3.

Force sword electrode 4 is made of a metal film such as an aluminum film. Force sword electrode 4 is formed on one main surface of semiconductor substrate 2.

The anode electrode 5 is composed of, for example, a metal film on which titanium, nickel, palladium and silver are sequentially deposited. The anode electrode 5 is formed on the other main surface of the semiconductor substrate 2.

Next, a procedure for manufacturing the mesa type diode 1 having the above-described configuration will be described in detail with reference to FIGS. 2 (a) to 2 (g). The following procedure is an example, and any procedure may be used as long as a similar result is obtained.

First, as shown in FIG. 2 (a), an n_ type semiconductor region (second semiconductor region 7) and a p + type semiconductor substrate 2 are formed by an epitaxial growth method, a thermal diffusion method, or the like. An n ⁺ type semiconductor region (third semiconductor region 8) is formed. The portion of the semiconductor substrate 2 excluding the second semiconductor region 7 and the third semiconductor region 8 constitutes the first semiconductor region 6. I have. In the present embodiment, the thicknesses of the first semiconductor region 6, the second semiconductor region 7, and the third semiconductor region 8 are 100 // πι, 40 m, and Ι Ι μπι, respectively. Was 240 μπι.

Next, as shown in FIG. 2B, an aluminum film '11 is formed on one main surface of the semiconductor substrate 2 by vacuum evaporation or the like. This aluminum film 11 constitutes a force source electrode 4 to be formed later. In the present embodiment, the thickness of aluminum film 11 is set to 8 μm.

Subsequently, for example, aluminum is vacuum-deposited on the other main surface of the semiconductor substrate 2 to form an aluminum film 12 as shown in FIG. 2 (b). The aluminum film 12 is for preventing the other main surface of the first semiconductor region 6 from being contaminated when a tape member described later is attached to the other main surface of the first semiconductor region 6. is there. The thickness of the aluminum film 12 is preferably about 1 // m to l0. In the present embodiment, the thickness is, for example, 2 μm.

Subsequently, an acid-resistant ink is printed on the aluminum film 11 using a screen technique using a nylon mesh mask or the like, thereby forming an etching mask on the aluminum film 11 as shown in FIG. 2 (c). Form 1 3 The etching mask 13 has an opening 13 a at a portion corresponding to a region where a mesa groove 9 is to be formed (a region where a mesa groove is to be formed). 3A is exposed through. The opening 13. A is formed in the form of a stitch on the main surface of the semiconductor substrate 2 when viewed two-dimensionally. For this reason, the etching mask 13 is formed in an island shape on one main surface of the semiconductor substrate 2.

Next, using the etching mask 13 as a mask, as shown in FIG. 2D, a portion of the aluminum film 11 corresponding to the opening 13a not covered with the etching mask 13 Is etched. That is, a portion of the aluminum film 11 corresponding to the region where the mesa groove is to be formed is removed. Aqua Regie was used as the etching solution for aluminum.

Further, a tape member 14 is attached to the lower surface of the aluminum film 12 (the surface not in contact with the other main surface of the semiconductor substrate 2).

Subsequently, the etching mask 13 and the aluminum film 11 are used as masks. Then, the region where the mesa groove is to be formed is etched through the opening 13a to form a mesa groove 9 having a U-shaped cross section as shown in FIG. 2 (e). In addition, the mesa groove 9 is formed in an annular shape along the outer peripheral edge of the semiconductor substrate 2 when viewed in plan. A mixed solution of nitric acid, hydrofluoric acid, acetic acid and sulfuric acid was used as an etching solution. In the present embodiment, the depth of the mesa groove 9 is set to 1605 / zm. As a result, the third semiconductor region 8, the second semiconductor region 7, the first semiconductor region 6, and the pn junction between the second semiconductor region 7 and the first semiconductor region 6 are exposed on the side surfaces of the mesa groove 9. In addition, the first semiconductor region 6 having a thickness of 80 m remains on the bottom surface of the mesa groove 9. Next, the portion of the aluminum film 11 shown in FIG. Is removed by etching so that the edge of the aluminum film 11 and the edge of the mesa groove 9 are aligned in a cross section as shown in FIG. 2 (f). Further, the etching mask 13 formed on the force source electrode 4 is removed. Further, the tape member 14 attached to the lower surface of the aluminum film 12 is removed.

Subsequently, as shown in FIG. 2G, the protective film 3 is formed so as to cover the inner surface of the mesa groove 9. If, for example, a polyimide resin is used as the material of the protective film 3, the protective film 3 can be formed at a temperature of about 200 ° C. to 500 ° C.

More specifically, first, a fluid polyimide resin is applied to the inner surface of the mesa groove 9 using a dispenser type applicator or the like. In order to form the protective film 3 by curing the applied polyimide resin, the resin is subjected to a heat treatment at 350 ° C. for 60 minutes for 20 minutes. The polyimide-based resin is heat-treated at a temperature of about 200 ° C. to 500 ° C. to evaporate a solvent contained in the resin and promote imide bond of the resin, thereby obtaining a relatively hard and dense resin. A film (protective film 3) is formed.

In this step, not only the polyimide resin but also the aluminum film 11 and the like are heated by the heat treatment.

There is no substantial damage to 25 1 1.

Next, the surface of the aluminum film 11 is lightly etched to form a force source electrode 4 composed of the aluminum film 11. Also, the aluminum film 12 is removed, and titanium, nickel, palladium and silver are sequentially vacuum-deposited on the other main surface of the semiconductor substrate 2 to form the anode electrode 5. Finally, the semiconductor substrate 2 is formed along the mesa groove 9. Dicing.

Through the above steps, the mesa diode 1 of the present embodiment is formed.

As described above, according to the present embodiment, after forming aluminum film 11 constituting force source electrode 4, semiconductor substrate 2 is etched using aluminum film 11 as a mask, and A groove 9 is formed. This eliminates the need to repeat a plurality of etching steps as in the prior art, in order to form the protective film 3 and the cathode electrode 4.

Further, in the present embodiment, since the protective film 3 is formed after the aluminum film 11 is formed, there is a problem that the protective film 3 remains on the edge of the region where the force source electrode is to be formed as in the related art. Will not occur. Since the aluminum film 11 can be formed first, the edge of the aluminum film 11 and the edge of the mesa groove 9 are easily aligned by etching as described above. For this reason, in the present embodiment, etching for forming the force sword electrode 4 can be performed more accurately than in the conventional technique.

Therefore, in the present embodiment, it is possible to form a mesa diode having improved productivity as compared with the related art.

Further, in the present embodiment, protective film 3 covering mesa groove 9 is formed by heat at a temperature lower than the temperature at which aluminum film 11 constituting force source electrode 4 deteriorates. For this reason, in the present embodiment, the heat hardly causes substantial damage to the aluminum film 11.

Note that the present invention is not limited to the above-described embodiment, and various modifications and applications are possible. For example, in the above embodiment, the temperature at which the metal film forming the force source electrode 4 is degraded by heat has been described by taking the melting point as an example. However, the temperature at which the metal film is degraded by heat is not limited to the melting point, but may be any temperature that substantially changes the properties (eg, resistivity) of the metal film.

In the above-described embodiment, the case where the polyimide resin is used for the protective film 3 has been described as an example. However, the material is not limited to this, and any material may be used as the material of the protective film 3 as long as the material of the force source electrode 4 can be formed at a temperature lower than the temperature at which the film quality of the material changes. That is, if the material of the protective film 3 can be heat-treated at a temperature that does not cause substantial damage to the material constituting the force source electrode 4, Anything is fine. In this case, the material forming the protective film 3 may be appropriately changed depending on the material forming the force source electrode 4.

In the above embodiment, the case where the tape member 14 (and the aluminum film 12) is formed on the other main surface of the first semiconductor region 6 has been described as an example, but the tape member 14 (and the aluminum film 1 2) need not be formed. In this case, the manufacturing process of the mesa-type diode 1 can be simplified as compared with the above-described embodiment, and a mesa-type diode with further improved productivity can be provided. Further, in the above-described embodiment, the case where the polyimide resin is applied to the mesa groove 9 using the dispenser type applicator has been described as an example, but the present invention is not limited to this, and various methods may be used. A polyimide resin may be applied to the mesa groove 9 without any problem. The semiconductor element of the above embodiment is not limited to the mesa diode, but may be any other mesa semiconductor element such as a mesa transistor. In this case, the mesa transistor may have the configuration shown in FIG. 3, for example. The illustrated mesa transistor la has the same configuration as that shown in FIG. 1 except for the p-type semiconductor region 21 and the n-type semiconductor region 22.

In the above embodiment, the aluminum film 11 constituting the cathode electrode 4 is formed on one main surface of the semiconductor substrate 2 by vacuum evaporation. However, the present invention is not limited to this. For example, the aluminum film 11 may be formed on one main surface of the semiconductor substrate 2 by sputtering.

As described above, according to the present invention, it is possible to provide a semiconductor device capable of improving the productivity of a semiconductor device and a method for manufacturing the same.

• The present invention is based on Japanese Patent Application No. 2002-6311 173 filed on March 8, 2002, and its description and claims The range and the whole drawing shall be taken. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention can be used for a mesa type semiconductor device.

Claims

The scope of the claims

1. A semiconductor substrate (2), an electrode (4) formed in a predetermined region on one main surface of the semiconductor substrate (2), and an outer periphery of the one main surface of the semiconductor substrate (2). The

(5) A method for manufacturing a mesa-shaped semiconductor element (1) comprising: a mesa groove (9) formed in a semiconductor substrate (2); and a protective film (3) covering an inner surface of the mesa groove (9). Forming a metal film (11) constituting the electrode in a predetermined region on one main surface of the semiconductor substrate (2);

Using the metal film (11) as a mask, forming the mesa groove (9) along the outer periphery of one main surface of the semiconductor substrate (2),

The protective film (3) is formed so as to cover the inner surface of the mesa groove (9) by using a material that is cured by heat at a temperature lower than the temperature at which the metal film (11) deteriorates. Dicing the semiconductor substrate I ⁵ plate (2) along the mesa groove (9) covered by (3);

A method for manufacturing a mesa-shaped semiconductor device, comprising:

2. forming the electrode (4) using aluminum, and forming the protective film (3) using a material that is cured by heat at a temperature of 100 ° C. to 400 ° C. lower than the melting point of aluminum; 2. The method for manufacturing a semiconductor device according to claim 1, wherein:

20 3. The method for manufacturing a semiconductor device according to claim 2, wherein the protective film (3) is formed from a polyimide resin.

4. A semiconductor substrate (2), a first electrode (4) formed in a predetermined region on one main surface of the semiconductor substrate (2), and a first electrode (4) formed on the other main surface of the semiconductor substrate (2) The second electrode (5), a mesa groove (9) formed in the semi-five conductor substrate (2) along the outer periphery of one main surface of the semiconductor substrate (2), and the mesa groove ( 9) In a mesa-type semiconductor device (1) comprising a protective film (3) covering the inner surface of

The first electrode (4) is composed of a metal film (1 1),

The protective film (3) is made of a material that is cured by heat at a temperature lower than the temperature at which the metal film (11) deteriorates. A semiconductor element characterized by the above-mentioned.

5. The mesa groove (9) is formed by etching one main surface of the semiconductor substrate (2) using the metal film (1 1) constituting the first electrode (4) as a mask. The semiconductor device according to claim 4, wherein the semiconductor device is formed by:

6. The semiconductor substrate (2) includes a second semiconductor of a second conductivity type in which an interface between the first semiconductor region (6) of the first conductivity type and the first semiconductor region (6) forms a pn junction. A third semiconductor region (8) in contact with the second semiconductor region (7) and having a higher concentration than the second semiconductor region (7). 5. The semiconductor device according to claim 4, wherein the semiconductor device is characterized in that:

7. The protective film (3) is made of a material that is cured by heat at a temperature 100 ° C to 400 ° C lower than the melting point of the metal film forming the first electrode (4). 5. The semiconductor device according to claim 4, wherein:

8. The first electrode (4) is made of aluminum,

The semiconductor device according to claim 7, wherein the protective film (3) is made of a material that is cured by heat at 200 ° (up to 500 ° C).

9. The semiconductor device according to claim 8, wherein the protective film (3) is made of a polyimide resin.