JP2014103348A - Semiconductor module and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor module capable of obtaining inexpensive and strong bonding, and a method of manufacturing the same.SOLUTION: A semiconductor chip 10 is mounted on a mounting substrate 20 by bonding a first electrode part 12 of the semiconductor chip 10 to a second electrode part 22 of the mounting substrate 20. In the first electrode part 12 and the second electrode part 22, a first copper nitride thin film is formed on a surface of a first copper electrode body 12a, and a second copper nitride thin film is formed on a surface of a second copper electrode body 22a by irradiation with nitrogen plasma. Then, the first copper nitride thin film and the second copper nitride thin film are brought into contact with each other and are heat-treated while being pressurized, thereby bonding the first electrode part 12 to the second electrode part 22 with a copper nitride 32 interposed therebetween.

Description

  The present invention relates to a semiconductor module and a manufacturing method thereof, and more particularly to a semiconductor module applied to chip mounting and a manufacturing method thereof.

  In a semiconductor chip such as a power device, a laser diode (Laser Diode), or a light emitting diode (Light Emitting Diode), heat generation during operation is relatively large. For this reason, it is necessary to provide a heat dissipation path to suppress an increase in the temperature of the semiconductor chip that causes a deterioration in the lifetime.

  The semiconductor chip is mounted (chip mounted) on a mounting substrate or a heat radiating plate on which electrodes, wiring, etc. (metallization) are formed. In order to efficiently cool the semiconductor chip, it is necessary to reduce the thermal resistance of the heat dissipation path. For this reason, many designs and manufacturing devices for reducing the thermal resistance of the joint have been proposed.

  Conventionally, solder mounting has been the mainstream, but in recent years, a mounting method using copper or silver having a high thermal conductivity as a joining member has attracted attention in order to further reduce thermal resistance. Among the members having high thermal conductivity, copper is excellent from the viewpoint of cost, and a structure and a manufacturing method are desired in which a joint portion from a semiconductor chip to a heat sink is formed only by copper.

  However, when copper is exposed to the atmosphere, an oxide film is formed on the surface in a relatively short time. When an oxide film is formed on the surface of copper, the temperature and pressure required for bonding become high and bonding becomes difficult. Moreover, since the copper oxide film is brittle, there is also a problem of deteriorating the bonding strength. In order to solve such problems, the following methods have been proposed.

  Patent Document 1 proposes a method for interposing a hydrocarbon compound exhibiting reducibility by thermal decomposition between one joining surface and the other joining surface, regarding a metal joining method using copper as a joining surface. . In this method, the copper oxide formed on the surface of the copper wiring is reduced by the hydrocarbon compound brought into a radical state by the heat at the time of bonding. Thereby, joining by a clean joining surface (copper surface) is attained.

  Patent Document 2 proposes a technique for joining electronic components to each other by a joining device that transports the electronic components from the pretreatment chamber to the treatment chamber in an airtight state. In this method, after the copper surface of the joint surface is reduced using formic acid in the pretreatment chamber, an inert gas is introduced into the pretreatment chamber. Next, the electronic components are transported to the bonding chamber in an inert gas atmosphere, and the electronic components are pressure bonded together in the bonding chamber. According to this method, it is possible to perform bonding in a state in which the copper surface is reduced, and it is possible to obtain strong bonding at a relatively low temperature.

  Patent Document 3 proposes a technique for joining electronic components using a metal nanoparticle paste. In this method, an electronic component is joined by sintering at a predetermined temperature using a copper nanoparticle paste that has been oxidized and prevented by a protective film containing a carboxylic acid. In this method, it is said that electronic components can be joined at a relatively low temperature.

  Patent Document 4 proposes a technique for sintering copper using nano-copper particles. In this method, copper nitride is thermally decomposed by using the nitrided nano copper particles to remove nitrogen, and at the same time, copper is sintered. According to this technique, copper can be bonded under a low temperature.

  Patent Document 5 proposes a technique for bonding substrates by irradiating the substrate with predetermined plasma. In this method, the substrate is bonded in a vacuum by irradiating the substrate with oxygen plasma and subsequently irradiating with nitrogen plasma. By this method, it is said that a strong and dense bonding can be realized by a low temperature process.

JP 2001-185843 A JP 2006-181641 A JP 2012-23014 A JP 2006-210872 A JP 2005-79353 A

  As described above, various techniques have been proposed for bonding substrates and the like. However, with regard to the bonding between copper and copper, it has not been possible to obtain a strong bonding at low temperatures using an inexpensive device and an inexpensive material.

  The present invention proposes an improvement regarding the bonding between copper and copper as part of the development of a semiconductor module, and one object is to provide a semiconductor module capable of obtaining a low-cost and strong bonding. An object of the present invention is to provide a method for manufacturing such a semiconductor module.

  The semiconductor module according to the present invention includes a semiconductor chip and a mounting substrate. In the semiconductor chip, a first electrode portion including a first copper electrode body is formed. In the mounting substrate, a second electrode portion including a second copper electrode body is formed. The semiconductor chip is bonded to the mounting substrate in such a manner that the first electrode portion and the second electrode portion are opposed to each other and copper nitride is interposed between the first copper electrode body and the second copper electrode body.

  The method for manufacturing a semiconductor module according to the present invention includes the following steps. In the semiconductor chip, a first electrode portion including a first copper electrode body is formed on the side bonded to the mounting substrate. In the mounting substrate, a second electrode part including a second copper electrode body is formed on the side to which the semiconductor chip is bonded. First copper nitride is formed on the surface of the first copper electrode body. Second copper nitride is formed on the surface of the second copper electrode body. The first electrode portion and the second electrode portion are opposed to each other, and the first copper portion and the second copper nitride are interposed between the first copper electrode body and the second copper electrode body. Two electrode parts are brought into close contact with each other and pressurized. The first electrode portion and the second electrode portion are heated at a predetermined temperature while being pressurized, and the first copper nitride and the second copper nitride are diffused, thereby interposing a bonding layer containing copper nitride therebetween. The 1 electrode part and the 2nd electrode part are joined.

According to the semiconductor module of the present invention, inexpensive and strong bonding can be obtained.
According to the method for manufacturing a semiconductor module according to the present invention, it is possible to manufacture a semiconductor module that is inexpensive and can provide strong bonding.

It is sectional drawing of the semiconductor module which concerns on Embodiment 1 of this invention. FIG. 10 is a cross-sectional view showing a step of the method of manufacturing a semiconductor module in the embodiment. FIG. 3 is a cross-sectional view showing a step performed after the step shown in FIG. 2 in the same embodiment. FIG. 4 is a cross-sectional view showing a step performed after the step shown in FIG. 3 in the same embodiment. FIG. 5 is a cross-sectional view showing a step performed after the step shown in FIG. 4 in the same embodiment. FIG. 6 is a cross-sectional view showing a step performed after the step shown in FIG. 5 in the same embodiment. FIG. 7 is a cross-sectional view showing a step performed after the step shown in FIG. 6 in the same embodiment. It is sectional drawing which shows 1 process of the manufacturing method of the semiconductor module which concerns on Embodiment 2 of this invention. FIG. 9 is a cross-sectional view showing a step performed after the step shown in FIG. 8 in the same embodiment. FIG. 10 is a cross-sectional view showing a step performed after the step shown in FIG. 9 in the same embodiment. FIG. 11 is a cross-sectional view showing a step performed after the step shown in FIG. 10 in the same embodiment. FIG. 12 is a cross-sectional view showing a step performed after the step shown in FIG. 11 in the same embodiment. FIG. 13 is a cross-sectional view showing a step performed after the step shown in FIG. 12 in the same embodiment. FIG. 14 is a cross-sectional view showing a step performed after the step shown in FIG. 13 in the same embodiment. FIG. 15 is a cross-sectional view showing a step performed after the step shown in FIG. 14 in the same embodiment. It is sectional drawing which shows 1 process of the manufacturing method of the semiconductor module which concerns on Embodiment 3 of this invention. FIG. 17 is a cross-sectional view showing a step performed after the step shown in FIG. 16 in the same embodiment. FIG. 18 is a cross-sectional view showing a step performed after the step shown in FIG. 17 in the same embodiment. FIG. 19 is a cross-sectional view showing a step performed after the step shown in FIG. 18 in the same embodiment. FIG. 20 is a cross-sectional view showing a step performed after the step shown in FIG. 19 in the same embodiment. FIG. 21 is a cross-sectional view showing a step performed after the step shown in FIG. 20 in the same embodiment. It is sectional drawing which shows 1 process of the manufacturing method of the semiconductor module which concerns on Embodiment 4 of this invention. FIG. 23 is a cross-sectional view showing a step performed after the step shown in FIG. 22 in the same embodiment. It is sectional drawing which shows 1 process of the manufacturing method of the semiconductor module which concerns on Embodiment 5 of this invention. FIG. 25 is a cross-sectional view showing a step performed after the step shown in FIG. 24 in the same embodiment. It is sectional drawing of the power module which concerns on Embodiment 6 of this invention.

Embodiment 1
First, the semiconductor module will be described. As shown in FIG. 1, in the semiconductor module 1, the semiconductor chip 10 is bonded to the mounting substrate 20. In the semiconductor chip 10, as an example of the semiconductor element 11, a Schottky barrier diode (SBD: Schottky Barrier Diode) is formed on a silicon substrate. The size of the Schottky barrier diode is, for example, 10 mm (vertical) × 10 mm (horizontal) × 150 μm (thickness). In the semiconductor chip 10, the first electrode portion 12 including the first copper electrode body 12 a is formed on the side facing the mounting substrate 20.

  The mounting substrate 20 is a ceramic substrate made of sintered alumina. The size of the ceramic substrate is, for example, 15 mm (length) × 15 mm (width) × 300 μm (thickness). This ceramic substrate is referred to as a DBC (registered trademark) substrate. On the mounting substrate 20, a second electrode portion 22 including a second copper electrode body 22 a is formed on the side facing the semiconductor chip 10.

  The semiconductor chip 10 is mounted on the mounting substrate 20 by bonding the first electrode portion 12 and the second electrode portion 22 together. Copper nitride 32 having a thickness of about 5 nm is interposed in the vicinity of the joining interface where the first electrode portion 12 and the second electrode portion 22 are joined. A copper nitride thin film 36 is formed as a protective film on the surfaces of the joined first electrode portion 12 and second electrode portion 22.

  In the semiconductor module 1 described above, the first electrode portion 12 and the second electrode portion 22 are bonded in a manner in which copper nitride is interposed, and the bonding interface does not contain copper oxide, so that the strength is high, and the heat Bonding reliability strong against history can be obtained.

  Next, a first example of a semiconductor module manufacturing method will be described. First, as shown in FIG. 2, a semiconductor chip 10 and a mounting substrate 20 that are semiconductor modules are prepared. A first electrode portion 12 including a first copper electrode main body 12 a is formed on one surface of the semiconductor chip 10. A second electrode portion 22 including a second copper electrode main body 22 a is formed on one surface of the mounting substrate 20.

Next, plasma processing is performed on the first electrode portion 12 and the second electrode portion 22. As shown in FIG. 3, the semiconductor chip 10 and the mounting substrate 20 are carried into a chamber 50 of an RF (Radio Frequency) plasma irradiation apparatus. Next, nitrogen gas is introduced into the chamber 50 and, for example, nitrogen (N ₂ ) plasma is irradiated to the semiconductor chip 10 and the mounting substrate 20 under an RF output of 100 W for about 30 seconds. By this nitrogen plasma irradiation, a first copper nitride thin film 14 is formed on the surface of the first copper electrode body 12a, and a second copper nitride thin film 24 is formed on the surface of the second copper electrode body 22a. Each film thickness of the first copper nitride thin film 14 and the second copper nitride thin film 24 is about 1 to 10 nm.

  Here, when the specification is such that two types of gas can be introduced into the chamber as the RF plasma irradiation apparatus, it is preferable to sequentially irradiate two types of plasma. That is, first, argon gas is introduced into the chamber 50, and the surface of the first copper electrode body 12a and the surface of the second copper electrode body 22a are cleaned by irradiating with argon (Ar) plasma. Forming the copper nitride thin film by irradiating with plasma enables the first electrode portion 12 and the second electrode portion 22 to be bonded more firmly.

  The thickness of each of the first copper nitride thin film 14 and the second copper nitride thin film 24 is preferably about 0.5 nm to 10 nm. When the film thickness is less than 0.5 nm, the first copper nitride thin film 14 or the second copper nitride thin film 24 is formed when the first electrode portion 12 and the second electrode portion 22 described later are pressed and brought into close contact with each other. The copper part of the first copper electrode body 12a or the second copper electrode body 22a may be exposed due to wear. When exposed copper is exposed to the atmosphere, the surface is oxidized, which may cause problems. On the other hand, when the film thickness is thicker than 10 nm, there is a high possibility that a large amount of nitrogen gas is generated, and there is a possibility that good bonding cannot be obtained.

  Next, as shown in FIG. 4, the semiconductor chip 10 and the mounting substrate 20 are arranged so that the first electrode portion 12 and the second electrode portion 22 face each other in the air at room temperature. Next, as shown in FIG. 5, the first electrode is formed in such a manner that the first copper nitride thin film 14 and the second copper nitride thin film 24 are interposed between the first copper electrode main body 12a and the second copper electrode main body 22a. The semiconductor chip 10 and the mounting substrate 20 are temporarily bonded by bringing the part 12 and the second electrode part 22 into close contact and applying pressure (see arrow 70). The pressure applied to pressurize the first electrode portion 12 and the second electrode portion 22 is preferably set to 0.1 MPa or more in order to promote close contact of the joint surfaces. On the other hand, in order to prevent the substrate of the semiconductor chip 10 from being broken, it is preferable to set the applied pressure to 50 MPa or less.

  Next, as shown in FIG. 6, the first copper nitride thin film 14 and the second copper nitride are heated by heating the semiconductor chip 10 and the mounting substrate 20 in the temporarily bonded state at a temperature of about 250 ° C. while applying pressure. In the portion where the thin film 24 is temporarily bonded, the copper nitride 32 (the first copper nitride thin film 14 and the second copper nitride thin film 24) is diffused to form the diffusion bonding layer 30. By forming the diffusion bonding layer 30, the semiconductor chip 10 and the mounting substrate 20 are substantially bonded from the temporarily bonded state. Further, in the portion of the first copper nitride thin film 14a and the portion of the second copper nitride thin film 24a exposed on the side surfaces of the first copper electrode main body 12a and the second copper electrode main body 22a, the copper nitride is decomposed and nitrogen is released. Then, a reduced copper thin film 34 is formed.

  The heating temperature at the time of this joining should just be 100 degreeC or more from which the diffusion of copper nitride begins. On the other hand, the higher the temperature, the faster the diffusion of copper nitride and the process time can be shortened. However, when the temperature is too high, nitrogen is suddenly released from the copper nitride and causes voids. For this reason, it is preferable that heating temperature is 300 degrees C or less.

  Here, the reduced copper thin film 34 exposed to the atmosphere may be oxidized. As already mentioned, the oxidation of copper causes problems. For this reason, it is preferable to form a protective film. Therefore, next, as shown in FIG. 7, the exposed reduced copper thin film 34 is again nitrided to form a copper nitride thin film 36 as a protective film. Thus, the semiconductor module 1 is completed.

  In the semiconductor module manufacturing method described above, the semiconductor chip 10 is mounted on the mounting substrate 20 by bonding the first electrode portion 12 of the semiconductor chip 10 to the second electrode portion 22 of the mounting substrate 20. In the first electrode portion 12 and the second electrode portion 22, by irradiating nitrogen plasma, the first copper nitride thin film 14 is formed on the surface of the first copper electrode body 12a, and on the surface of the second copper electrode body 22a. A second copper nitride thin film 24 is formed. Then, the first electrode unit 12 is formed in such a manner that the copper nitride 32 (diffusion bonding layer 30) is interposed by applying heat treatment while bringing the first copper nitride thin film 14 and the second copper nitride thin film 24 into contact with each other and applying pressure. Joined to the two-electrode portion 22.

  As a result, plasma irradiation which is widely used without using a bonding apparatus in which electronic components are transported from the pretreatment chamber to the treatment chamber in an airtight state and without using expensive materials such as nanoparticles. The semiconductor module 1 in which copper (first electrode portion 12) and copper (second electrode portion 22) are firmly and densely joined can be manufactured using an apparatus or a heat treatment apparatus.

Embodiment 2
Here, the case where a copper electrode main body and a copper nitride thin film are formed using a sputtering method will be described as a second example of the semiconductor module manufacturing method. The same members as those in the semiconductor module manufacturing method described in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated unless necessary.

  First, as shown in FIG. 8, a semiconductor element 11 that is a semiconductor chip and in which a Schottky barrier diode is formed on a semiconductor substrate, and a ceramic substrate 20a that is a mounting substrate are prepared. Next, as shown in FIG. 9, the semiconductor element 11 and the ceramic substrate 20a are transported into a chamber 51 of the sputtering apparatus. Next, by depositing copper by sputtering, a copper film 12b is formed on the surface of the semiconductor element 11, and a copper film 22b is formed on the surface of the ceramic substrate 20a.

  Subsequent to the formation of the copper films 12b and 22b, as shown in FIG. 10, the first copper nitride thin film 14b is formed on the surface of the copper film 12b by depositing copper nitride by sputtering, and the surface of the copper film 22b. A second copper nitride thin film 24b is formed thereon.

  Next, as shown in FIG. 11, the first electrode portion 12 including the first copper electrode body 12a is formed by patterning the copper film 12b and the like formed on the surface of the semiconductor element 11. A first copper nitride thin film 14b is formed on the surface (excluding side surfaces) of the first copper electrode body 12a. Moreover, the 2nd electrode part 22 containing the 2nd copper electrode main body 22a is formed by patterning the copper film 22b etc. which were formed in the surface of the ceramic substrate 20a. A second copper nitride thin film 24b is formed on the surface (excluding side surfaces) of the second copper electrode body 22a. Thus, the semiconductor chip 10 and the mounting substrate 20 are formed.

  Next, as shown in FIG. 12, the semiconductor chip 10 and the mounting substrate 20 are arranged so that the first electrode portion 12 and the second electrode portion 22 face each other in the air at room temperature. Next, as shown in FIG. 13, the first electrode is formed by interposing the first copper nitride thin film 14 and the second copper nitride thin film 24 between the first copper electrode main body 12a and the second copper electrode main body 22a. The semiconductor chip 10 and the mounting substrate 20 are temporarily bonded by bringing the part 12 and the second electrode part 22 into close contact and applying pressure (see arrow 70). At this time, as described in the process shown in FIG. 5, it is preferable to set the pressure applied to the first electrode portion 12 and the second electrode portion 22 to 1 MPa or more and 50 MPa or less.

  Next, as shown in FIG. 14, the first copper nitride thin film 14 and the second copper nitride are heated by heating the semiconductor chip 10 and the mounting substrate 20 in the temporarily bonded state at a temperature of about 250 ° C. while applying pressure. In the portion where the thin film 24 is temporarily bonded, the copper nitride 32 (the first copper nitride thin film 14 and the second copper nitride thin film 24) is diffused to form the diffusion bonding layer 30. As described in the process shown in FIG. 6, by forming the diffusion bonding layer 30, the semiconductor chip 10 and the mounting substrate 20 are substantially bonded. Moreover, the 2nd copper nitride thin film 24 exposed on the upper surface of the 2nd copper electrode main body 22a decomposes | disassembles, and the reduced copper thin film 34 is formed.

  Next, as described in the process shown in FIG. 7, a protective film is formed. As shown in FIG. 15, the exposed surfaces of the first copper electrode body 12a, the second copper electrode body 22a, and the reduced copper thin film 34 are nitrided again, thereby forming a copper nitride thin film 36 as a protective film. Thus, the semiconductor module 1 is completed.

  In the semiconductor module manufacturing method described above, the semiconductor chip 10 is mounted on the mounting substrate 20 by bonding the first electrode portion 12 of the semiconductor chip 10 to the second electrode portion 22 of the mounting substrate 20. In the semiconductor chip 10 and the mounting substrate 20, the first electrode part 12 including the first copper electrode body 12a and the second electrode part 22 including the second copper electrode body 22a are formed by sputtering. Further, the first copper nitride thin film 14 is formed on the surface of the first copper electrode body 12a and the second copper nitride thin film 24 is formed on the surface of the second copper electrode body 22a by sputtering. Then, the first electrode unit 12 is formed in such a manner that the copper nitride 32 (diffusion bonding layer 30) is interposed by applying heat treatment while bringing the first copper nitride thin film 14 and the second copper nitride thin film 24 into contact with each other and applying pressure. Joined to the two-electrode portion 22.

  As a result, a sputtering apparatus that is widely used without using a bonding apparatus in which electronic components are transported from the pretreatment chamber to the processing chamber in an airtight state, and without using an expensive material such as nanoparticles. Alternatively, a semiconductor module in which copper (first electrode portion 12) and copper (second electrode portion 22) are firmly and densely joined can be manufactured using a heat treatment apparatus.

Embodiment 3
Here, the case where a copper plate is applied as a mounting substrate will be described as a third example of the method for manufacturing a semiconductor module. The same members as those in the semiconductor module manufacturing method described in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated unless necessary.

  First, as shown in FIG. 16, a semiconductor chip 10 and a mounting substrate 20 to be a semiconductor module are prepared. As the mounting substrate 20, a copper plate 20b is applied. The copper plate 20b also serves as the second electrode portion 22 (second copper electrode body 22a). The size of the copper plate 20b is, for example, 15 mm (length) × 15 mm (width) × 300 μm (thickness), and is cut out from the oxygen-free copper plate.

  Next, nitrogen plasma is irradiated in the same manner as in the step shown in FIG. As shown in FIG. 17, the semiconductor chip 10 and the mounting substrate 20 are carried into the chamber 50 and irradiated with nitrogen plasma, whereby the first copper nitride thin film 14 (14a) is formed on the surface of the first copper electrode body 12a. The second copper nitride thin film 24 (24a) is formed on the surface of the second copper electrode body 22a.

  Next, as shown in FIG. 18, the semiconductor chip 10 and the mounting substrate 20 are arranged so that the first electrode portion 12 and the second electrode portion 22 face each other in the air at room temperature. Next, as shown in FIG. 19, the first electrode is formed in such a manner that the first copper nitride thin film 14 and the second copper nitride thin film 24 are interposed between the first copper electrode main body 12a and the second copper electrode main body 22a. The semiconductor chip 10 and the mounting substrate 20 are temporarily bonded by bringing the part 12 and the second electrode part 22 into close contact and applying pressure (see arrow 70).

  Next, as shown in FIG. 20, the first copper nitride thin film 14 and the second copper nitride are heated by heating the semiconductor chip 10 and the mounting substrate 20 in the temporarily bonded state under a temperature of about 250 ° C. In the portion where the thin film 24 is temporarily bonded, the copper nitride 32 (the first copper nitride thin film 14 and the second copper nitride thin film 24) is diffused to form the diffusion bonding layer 30. By forming the diffusion bonding layer 30, the semiconductor chip 10 and the mounting substrate 20 are substantially bonded from the temporarily bonded state. Further, the exposed first copper nitride thin film 14 and the second copper nitride thin film 24 are decomposed on the side surfaces of the first copper electrode main body 12a and the second copper electrode main body 22a, and the reduced copper thin film 34 is formed. . Next, as shown in FIG. 21, the exposed reduced copper thin film 34 is again nitrided to form a copper nitride thin film 36 as a protective film. Thus, the semiconductor module 1 is completed.

  In the semiconductor module manufacturing method described above, the semiconductor chip 10 is mounted on the mounting substrate 20 by bonding the first electrode portion 12 of the semiconductor chip 10 to the second electrode portion 22 of the mounting substrate 20. As the mounting substrate 20, a copper plate 20b including the function of the second electrode portion 22 (second copper electrode main body 22a) is applied. In the first electrode portion 12 and the second electrode portion 22 (copper plate 20b), the first copper nitride thin film 14 is formed on the surface of the first copper electrode body 12a by irradiating nitrogen plasma, and the second copper electrode body A second copper nitride thin film 24 is formed on the surface of 22a (copper plate 20b). Then, the first electrode unit 12 is formed in such a manner that the copper nitride 32 (diffusion bonding layer 30) is interposed by applying heat treatment while bringing the first copper nitride thin film 14 and the second copper nitride thin film 24 into contact with each other and applying pressure. Joined to the two-electrode portion 22.

  As a result, plasma irradiation which is widely used without using a bonding apparatus in which electronic components are transported from the pretreatment chamber to the treatment chamber in an airtight state and without using expensive materials such as nanoparticles. A semiconductor module in which copper (first electrode portion 12) and copper (second electrode portion 22) are firmly and densely joined can be manufactured using an apparatus or a heat treatment apparatus. Moreover, it can apply to the semiconductor (power) module of various forms by applying the copper plate 20b.

Embodiment 4
Here, a case where a copper nitride thin film is formed using an ammonia solution will be described as a fourth example of the semiconductor module manufacturing method. The same members as those in the semiconductor module manufacturing method described in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated unless necessary.

  First, similarly to the process shown in FIG. 2, a semiconductor chip 10 and a mounting substrate 20 to be a semiconductor module are prepared (see FIG. 2). Next, copper is nitrided with an ammonia solution. As shown in FIG. 22, an ammonia solution 54 is prepared in the chemical tank 52. The concentration of the ammonia solution 54 is about 25%, for example. The temperature of the ammonia solution 54 is set to about 40 ° C. The semiconductor chip 10 and the mounting substrate 20 are immersed in the ammonia solution 54 for about 10 minutes.

  As a result, a first copper nitride thin film 14 having a thickness of about 1 to 10 nm is formed on the surface of the first copper electrode body 12a. A second copper nitride thin film 24 having a thickness of about 1 to 10 nm is also formed on the surface of the second copper electrode body 22a (see FIG. 4 and the like).

  Thereafter, through steps similar to those shown in FIGS. 4 to 7 (Embodiment 1), the first electrode portion 12 of the semiconductor chip 10 is replaced with the second electrode portion 22 of the mounting substrate 20 as shown in FIG. Thus, the semiconductor module 1 bonded to is obtained. As shown in FIG. 23, a diffusion bonding layer 30 in which copper nitride 32 is diffused is interposed between the first copper electrode body 12 a of the first electrode portion 12 and the second copper electrode body 22 a of the second electrode portion 22. To do.

  In the semiconductor module manufacturing method described above, the first copper nitride thin film 14c and the second copper nitride thin film 24c are obtained by immersing the first copper electrode body 12a and the second copper electrode body 22a in an ammonia solution instead of the plasma treatment. Is formed. Thereby, it can contribute to reduction of equipment cost.

  In the semiconductor module manufacturing method described above, the case where both the semiconductor chip 10 and the mounting substrate 20 are immersed in the same ammonia solution 54 has been described. However, the semiconductor chip 10 and the mounting substrate 20 are separately put into an ammonia solution. You may make it soak.

Embodiment 5
Here, a case where a copper nitride thin film is formed using ammonia gas will be described as a fifth example of the semiconductor module manufacturing method. The same members as those in the semiconductor module manufacturing method described in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated unless necessary.

  First, similarly to the process shown in FIG. 2, a semiconductor chip 10 and a mounting substrate 20 to be a semiconductor module are prepared (see FIG. 2). Next, nitriding of copper is performed with ammonia gas. As shown in FIG. 24, the semiconductor chip 10 and the mounting substrate 20 are carried into the chamber 50. Ammonia gas 56 is introduced into the chamber 50, and the temperature in the chamber is set to about 300 ° C. The semiconductor chip 10 and the mounting substrate 20 are exposed to the ammonia gas for about 10 hours.

  As a result, a first copper nitride thin film 14 having a thickness of about 1 to 10 nm is formed on the surface of the first copper electrode body 12a. A second copper nitride thin film 24 having a thickness of about 1 to 10 nm is also formed on the surface of the second copper electrode body 22a (see FIG. 4 and the like).

  Thereafter, through steps similar to those shown in FIGS. 4 to 7 (Embodiment 1), the first electrode portion 12 of the semiconductor chip 10 becomes the second electrode portion 22 of the mounting substrate 20 as shown in FIG. Thus, the semiconductor module 1 bonded to is obtained. As shown in FIG. 25, a diffusion bonding layer 30 in which copper nitride 32 is diffused is interposed between the first copper electrode body 12 a of the first electrode portion 12 and the second copper electrode body 22 a of the second electrode portion 22. To do.

  In the semiconductor module manufacturing method described above, the first copper nitride thin film 14c and the second copper nitride thin film 24c are formed by exposing the first copper electrode body 12a and the second copper electrode body 22a to ammonia gas instead of the plasma treatment. It is formed. Thereby, it can contribute to reduction of equipment cost.

  In the semiconductor module manufacturing method described above, the case where both the semiconductor chip 10 and the mounting substrate 20 are exposed to the same ammonia gas has been described. However, the semiconductor chip 10 and the mounting substrate 20 are separately exposed to ammonia gas. It may be.

Embodiment 6
Here, a method for manufacturing a power semiconductor module to which the semiconductor module is applied will be described. The same members as those in the semiconductor module manufacturing method described in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated unless necessary.

  A semiconductor chip 10 to which GaN or the like is applied is prepared as a semiconductor chip. Further, a mounting substrate 20 to which a ceramic substrate made of alumina, silicon nitride, or the like is applied is prepared as the mounting substrate. Next, the first electrode portion 12 of the semiconductor chip 10 is bonded to the mounting substrate 20 through the same steps as those shown in FIGS. 3 to 7 (first embodiment) (see FIG. 7).

  Next, as shown in FIG. 26, a side of the ceramic substrate (mounting substrate 20) opposite to the side on which the semiconductor chip 10 is mounted is bonded to the heat sink 60. Thus, the power semiconductor module 2 is completed.

  In the method of manufacturing the power semiconductor module described above, the semiconductor chip 10 is mounted on the mounting substrate by bonding the first copper electrode body 12a and the second copper electrode body 22a with the copper nitride 32 (diffusion bonding layer 30) interposed. 20 is implemented.

  Thereby, the thermal resistance from the semiconductor chip 10 to the heat sink 60 through the mounting substrate 20 is greatly reduced as compared with the case where the semiconductor chip is bonded to the mounting substrate by solder. As a result, the allowable amount for the heat generation amount is improved, the characteristics as the power semiconductor module 2 are improved, and the life of the power semiconductor module 2 can be extended. Furthermore, since the thermal resistance is greatly reduced, the size of the semiconductor chip 10 can be reduced, the cooling function can be simplified, and the cost can be reduced.

  In the semiconductor module described above, a Schottky barrier diode has been described as an example of a semiconductor element formed on a semiconductor chip. The semiconductor element is not limited to this, and can be applied to other power semiconductor elements such as an IGBT (Insulated Gate Bipolar Transistor), a laser diode, or a light emitting diode.

  The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the terms of the claims, rather than the scope described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is effectively used for a semiconductor module in which a semiconductor chip having a relatively large amount of heat generation is mounted on a mounting substrate.

  DESCRIPTION OF SYMBOLS 1 Semiconductor module, 2 Power module, 10 Semiconductor chip, 11 Semiconductor element, 11a Schottky barrier diode, 12 1st electrode part, 12a 1st copper electrode main body, 12b Copper film, 14, 14a, 14b, 14c, 14d 1st Copper nitride thin film, 20 mounting substrate, 20a ceramic substrate, 20b copper plate, 22 second electrode part, 22a second copper electrode body, 22b copper film, 24, 24a, 24b, 24c, 24d second copper nitride thin film, 30 diffusion bonding Layer, 32 Copper nitride, 34 Reduced copper thin film, 36 Copper nitride thin film, 50, 51 Chamber, 52 Chemical bath, 54 Ammonia aqueous solution, 56 Ammonia gas, 60 Heat sink, 70 Arrows.

Claims (15)

A semiconductor chip on which a first electrode portion including a first copper electrode body is formed;
A mounting substrate on which a second electrode portion including a second copper electrode body is formed,
In the semiconductor chip, the first electrode portion and the second electrode portion are opposed to each other, and copper nitride is interposed between the first copper electrode body and the second copper electrode body. Bonded semiconductor module.   The semiconductor module according to claim 1, wherein a copper nitride thin film is formed as a protective film so as to cover a side surface of the first copper electrode body and a side surface of the second copper electrode body. The mounting substrate includes a ceramic substrate,
3. The semiconductor module according to claim 1, wherein the second copper electrode main body is disposed at a position corresponding to the first copper electrode main body on the ceramic substrate.   The semiconductor module according to claim 1, wherein the mounting board is a copper plate including the second copper electrode main body.   5. The semiconductor module according to claim 1, wherein a side of the mounting substrate opposite to a side on which the second copper electrode main body is disposed is bonded to a heat sink. Forming a first electrode portion including a first copper electrode body on a side bonded to a mounting substrate in a semiconductor chip;
Forming a second electrode part including a second copper electrode main body on the side to which the semiconductor chip is bonded in the mounting substrate;
Forming a first copper nitride on the surface of the first copper electrode body;
Forming a second copper nitride on the surface of the second copper electrode body;
In an aspect in which the first electrode part and the second electrode part are opposed to each other, and the first copper nitride and the second copper nitride are interposed between the first copper electrode body and the second copper electrode body, Pressing the first electrode part and the second electrode part in close contact with each other;
The first electrode portion and the second electrode portion are heated at a predetermined temperature while being pressurized, and the first copper nitride and the second copper nitride are diffused to form a bonding layer containing copper nitride. A method of manufacturing a semiconductor module, comprising a step of interposing the first electrode portion and the second electrode portion. The step of forming the first copper electrode main body and the step of forming the first copper nitride include a first copper film as the first copper electrode main body and a first copper nitride as the first copper nitride by sputtering. Including a step of continuously forming a film,
The step of forming the second copper electrode and the step of forming the second copper nitride include a second copper film as the second copper electrode body and a second copper nitride film as the second copper nitride by sputtering. The manufacturing method of the semiconductor module of Claim 6 including the process of forming each continuously.   The method for manufacturing a semiconductor module according to claim 6, wherein a copper plate including the second copper electrode main body is used as the mounting substrate.   The step of forming the first copper nitride and the step of forming the second copper nitride include irradiating the surface of the first copper electrode body and the surface of the second copper electrode body with nitrogen plasma, respectively. A method for manufacturing a semiconductor module according to claim 6.   The step of forming the first copper nitride and the step of forming the second copper nitride include a step of immersing the first copper electrode body and the second copper electrode body in an ammonia solution, respectively. Manufacturing method of semiconductor module.   The step of forming the first copper nitride and the step of forming the second copper nitride include a step of exposing the first copper electrode body and the second copper electrode body to ammonia gas, respectively. Manufacturing method of semiconductor module.   12. The semiconductor module according to claim 6, wherein, in the step of joining the first electrode part and the second electrode part, the predetermined temperature is set to 100 ° C. or more and 300 ° C. or less. Manufacturing method.   The thickness of the first copper nitride and the thickness of the second copper nitride are 0.5 nm or more and 10 nm or less in the step of forming the first copper nitride and the step of forming the second copper nitride. The manufacturing method of the semiconductor module of any one of 6-12.   14. The method according to claim 6, further comprising: nitriding the exposed surfaces of the first copper electrode body and the second copper electrode body after joining the first electrode part and the second electrode part. A manufacturing method of a semiconductor module given in any 1 paragraph.   The manufacturing method of the semiconductor module of any one of Claims 6-14 provided with the process of joining the said mounting board | substrate to a heat sink.

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