JP2014075565A - Method of manufacturing compound semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high thermal conductivity in a GaN substrate for high voltage driving element.SOLUTION: After forming an element by forming a GaN element on a sapphire substrate, a glass substrate is stuck to the element surface via a UV peelable material. Subsequently, the sapphire substrate and a GaN layer are removed by laser irradiation. Thereafter, the back side of the GaN element thus removed is metallized and a heat sink substrate is stuck thereto. Under that state, the glass surface is irradiated with UV light, thus removing the glass substrate. Consequently, a GaN element is formed on a heat sink. Since the heat sink substrate has a two-layer structure of a conductive heat sink material, and an insulating material, the element potential and the lead frame potential can be isolated.

Description

  The present invention relates to a method for manufacturing a semiconductor device using a power compound semiconductor, particularly a GaN substrate or SiC substrate.

  FIG. 1 shows a cross section of an element of a junction FET (JFET) using a conventionally published gallium nitride (GaN) substrate. 1A shows an element structure in which a GaN thin film layer 2 having a thickness of 10 μm is formed on a Si substrate 1 and a junction type gate portion becomes a gate 13 in the layer to control conduction between the drain 12 and the source 11 of the FET. It is sectional drawing shown. A load voltage of several hundred volts is applied between the drain and source, and the gate is in a conductive state (on state) when the ground voltage (the same potential as the source) is applied. 14 spreads to a non-conducting state (off state). FIG. 1B shows a state in which a wiring is formed on the surface layer, and a gate electrode 23, a drain electrode 22 and a source electrode 21 which are electrodes as GaN elements are formed. The thickness of Si, which is the base substrate, is 400 μm in order to ensure rigidity in the manufacturing process in the wafer state with a diameter of 4 inches. In order to achieve this, the metallization processing is performed for thinning to 50 μm and soldering on the back surface.

  FIG. 2 shows the GaN element taken out as an individual element and mounted on a lead frame. 2A shows that the GaN device of FIG. 1 is soldered to the lead frame via a heat sink or mounted via a high and low heat conductive adhesive, and an external gate and an external drain 32 of the lead frame by wire bonding 34. FIG. The state of being electrically connected to the external source 31 is shown. The heat sink 40 is provided to make the heat distribution generated in the GaN element uniform and transmit it to the lead frame 33, or to absorb the transient heat generated when the element is switched. FIG. 2B shows a structure in which the heat sink part is divided into two layers of a conductive part 41 made of a conductive material and a heat sink part made of an insulating part 42 made of an insulating material. In this structure, the potential of the lead frame is separated from the potential of the element substrate portion.

  The problem as a power semiconductor having this general structure lies in a heat transfer path generated in the GaN element portion. The main heat conduction is through the Si substrate to the lead frame via the heat sink, but because the heat conductivity of the Si substrate is low, the heat generated in the GaN element is led through the heat sink to the lead frame. It has a structure that is difficult to communicate with. That is, the problem is that the thermal resistance from the GaN element to the lead frame is large. The element temperature rises due to the heat generated in the GaN element, and it becomes difficult for current to flow, which falls into a vicious circle that further increases heat generation. Thus, it is indispensable to stably operate the device by lowering the temperature of the GaN device, which rises due to heat generated in the GaN device, as much as possible by heat conduction.

In order to reduce the thermal resistance from the GaN device to the lead frame in this structure, it is conceivable to reduce the thickness of the Si substrate, but for handling to separate the device from the wafer state and mount the device. 50 μm thickness is the minimum required thickness. Further, in this structure, it is necessary to enlarge the GaN element in order to disperse the heat generated in the GaN element in the GaN element. This increases the price of the GaN semiconductor. In order to improve heat conduction, the size of the GaN element must be increased not only to reduce the on-state loss of the element but also to increase heat conduction, that is, whether the heat conduction is good or bad. This means that it is an important factor that affects the size of the device and also has a large impact on the cost.

Further, in order to lower the thermal resistance from the GaN element to the lead frame in this structure, it is possible to use SiC as a semiconductor substrate having good thermal conductivity in addition to the Si substrate. Thereby, the heat conduction from the element to the lead frame is improved, and in the element of the SiC substrate, it is possible to reduce the size of the element intentionally increased in the element of the Si substrate. However, with a SiC substrate, the problem is that the substrate cost is high and the polishing cost is high because the SiC substrate is hard. There are advantages and disadvantages when using a Si substrate and a SiC substrate.

An object of the present invention is to apply a new structure to such a heat conducting structure from the GaN element to the lead frame, and to operate stably while suppressing cost reduction and temperature increase of the GaN element part. The point of interest in FIG. 2A is the relationship between the heat sink and the Si substrate. If the heat sink becomes the foundation of the GaN element part instead of the Si substrate rather than as an inclusion when the GaN element is mounted on the lead frame, the disadvantage that the heat conduction of the Si substrate is not good can be eliminated. This can improve the point that the size of the element is increased due to the poor thermal conductivity. 2B, the heat sink is not an inclusion when the GaN element is mounted on the lead frame, but serves as a foundation for the GaN element portion instead of the Si substrate, and the heat sink is composed of a conductive material and an insulating material. In the case of a layer structure, an insulating structure can be taken while eliminating the disadvantage that the heat conduction of the Si substrate is not good.

In order to realize the result of this consideration, a structure in which the substrate necessary for handling the substrate of the GaN element becomes a heat sink in the final stage of the wafer state is put into practical use. On the other hand, in the process of forming a GaN element in a 10 μm-thick GaN thin film, it is necessary to withstand a high temperature of 1000 ° C. or higher. Therefore, when forming the element, the substrate may be a Si substrate or a SiC substrate, Substrate is required. Metals such as copper and molybdenum used as a heat sink material melt and oxidize. With this in mind, the main point of the present invention is to use a Si substrate or other high heat resistant substrate in the GaN element process, and convert the heat sink substrate from these high heat resistant substrates immediately before element separation. It becomes.

Means for solving the above problems will be described below.
1. A method of manufacturing a semiconductor device using a first compound semiconductor (GaN),
The first base substrate or the substrate formed by forming the second compound semiconductor layer on the surface of the base substrate or the substrate formed by forming the third compound semiconductor layer on the surface of the base substrate is used as the first substrate, Forming a first compound semiconductor on the surface of the first substrate;
Forming a semiconductor element by forming at least one of a P-type region and an N-type region in the first compound semiconductor layer and forming an electrode; and
A first bonding step of bonding the surface of the semiconductor element formed by the semiconductor element formation step and the surface of the second substrate;
A first substrate removing step of removing the first substrate after the first bonding step;
A second substrate removing step of bonding the surface from which the first substrate has been removed by the first substrate removing step and a third substrate, and then removing the second substrate;
A method for manufacturing a semiconductor device, comprising:
2. 2. The method of manufacturing a semiconductor device according to claim 1, wherein in the second substrate removing step, the second substrate is removed after the semiconductor element is separated and mounted on a mounting substrate.
3. The method for manufacturing a semiconductor device according to claim 1, wherein the base substrate is a sapphire substrate, and the second compound semiconductor is a Ga-based compound semiconductor.
4). 4. The method of manufacturing a semiconductor device according to claim 3, wherein the first substrate removing step removes the first substrate by irradiating a surface of the sapphire substrate on which the Ga-based compound semiconductor is formed with laser light.
5. The method for manufacturing a semiconductor device according to claim 1, wherein the base substrate is a silicon substrate.
6). 4. The method of manufacturing a semiconductor device according to claim 3, wherein in the first substrate removing step, the silicon substrate is thinned, and thereafter the silicon substrate is removed or the first substrate is removed by chemical etching at the final stage of thinning. .
7). The second substrate is transparent glass;
In the second bonding step, an adhesive layer using a material that is peeled off by light is formed on the surface of the semiconductor element, and then bonded to the surface of the second substrate through the adhesive layer.
The second substrate removing step removes the second substrate by irradiating with light.
A method for manufacturing a semiconductor device according to claim 1.
8). The method of manufacturing a semiconductor device according to claim 1, wherein the first compound semiconductor is gallium nitride (GaN).
9. The method for manufacturing a semiconductor device according to claim 1, wherein the third compound semiconductor is silicon carbide (SiC).
10. The method for manufacturing a semiconductor device according to claim 1, wherein the third substrate is a heat sink material.
11. The method for manufacturing a semiconductor device according to claim 1, wherein the third substrate is a material having a two-layer structure of a conductive heat sink material and an insulating material.

Although there are great expectations for the practical application of GaN devices suitable for high-voltage driving, the expansion of their applications has been limited so far due to the limitations of device cost, stability of characteristics, and heat generated in the devices. According to the present invention, it is possible to reduce the cost by looking through from the substrate for the GaN element to the mounting. This revolutionary cost reduction structure contributes to industrial development.

  Sectional view showing the structure of a GaN layer and a junction FET element formed on a known Si substrate   Device mounting cross section   Manufacturing process, device transition and device cross-sectional view for realizing the device structure according to the present invention   Device mounting cross section   Cross-sectional view of a manufacturing process and device for realizing another device structure according to the present invention   Device mounting cross section   Method for producing a substrate used in the present invention   Cross-sectional view of the device and another manufacturing process for realizing the device structure according to the present invention

The embodiment for carrying out the present invention minimizes the use of an expensive GaN layer through a simple process and an inexpensive material as seen through from substrate formation to element formation and a heat sink material used for mounting. . Specifically, paying attention to the fact that a heat sink (see FIG. 2) is essential in the power element, the heat base can be mounted without using the Si base substrate as a support base, and the use of the Si base substrate is recommended. It is to make it unnecessary. This improves heat conduction and reduces the size of the GaN element. The heat generated in the element formed in the GaN layer having a thickness of 10 μm is directly transmitted to the heat sink substrate by eliminating the substrate such as Si, and is transmitted to the lead frame. However, in order to form a GaN film on a substrate (first substrate) that serves as a support base for a GaN element, it is necessary to perform processing at a high temperature of 1000 ° C. or higher. A heat sink substrate made of metal has a thermal expansion coefficient. Limited by melting point and oxidation. For this reason, a heat sink that becomes a support base when mounting cannot be used as a support base in the GaN element manufacturing process. For this reason, a sapphire substrate that can withstand high temperatures is used as a support for the GaN film, and after the GaN element fabrication process, the sapphire substrate is removed and replaced with a heat sink material. At the time of replacement, prior to the removal of the sapphire substrate (first substrate) that is a support base, an inexpensive glass substrate (second substrate) is bonded to the element surface side that is the opposite surface to form a temporary support base. . In that state, the sapphire substrate (first substrate) is removed, and the heat sink substrate (third substrate) is placed on the surface from which the sapphire substrate (first substrate) is removed using the glass substrate (second substrate) as a support. to paste together. In this state, the support base is a heat sink substrate, and the glass substrate can be removed. With this configuration, the heat transfer between the GaN element and the heat sink can be in an ideal state. The glass substrate preferably has the same thermal expansion coefficient as that of the semiconductor element, and alkali-free glass can be used. The glass substrate can be reused after polishing. The sapphire substrate can be easily removed by laser lift-off using the glass substrate as a support. Sapphire substrates can also be reused after polishing. In addition, the heat sink substrate is made of a material having a two-layer structure of a conductive and heat conductive material and an insulating material, so that the potential of the lead frame on which the element is mounted and the substrate potential of the GaN element are separated. It is possible to achieve a structure in which the degree of freedom in circuit configuration is increased.

  As a specific procedure, a sapphire substrate on which a Ga-based compound semiconductor thin film layer (second thin film) is formed (a base substrate and a substrate on which the second compound semiconductor layer is formed on the base substrate are referred to as a first substrate). A GaN film having a thickness of 10 μm is formed on the thin film surface of the Ga-based compound semiconductor, and then a GaN element is formed on the GaN film. The sapphire substrate is an inexpensive substrate with good flatness that has been put into practical use in recent light-emitting diode applications. Further, the reason why the thin film layer of the Ga-based compound semiconductor is interposed is to use it for peeling the sapphire substrate later by a laser lift-off technique. The Ga-based compound semiconductor may be GaN, but it is necessary to form a thin film having a thickness of several μm separately from the element formation. The element formed on the GaN film is a junction gate type FET, and in the element formation process, it is necessary to withstand a high temperature of 1000 or more to activate the P-type region and the N-type region. It is a material having a melting point of 2000 ° C. or higher and sufficiently high heat resistance. The sapphire substrate is a base substrate that can withstand this high temperature, and is a material that easily allows laser light to pass through and easily peels off later in the Ga-based compound semiconductor layer. The source, gate and drain of the junction gate type FET are formed, electrodes are formed (element formation), and then a transparent glass substrate (second substrate), which will eventually become unnecessary, is bonded to an adhesive or sheet. Bonding is performed on the surface on which the junction gate type FET is formed via a material. The adhesive is an ultraviolet light peeling material that can peel the glass substrate attached by ultraviolet irradiation. After glass bonding, this glass substrate becomes a support and can be handled in the wafer state, so that the sapphire substrate can be removed. This removal of the sapphire substrate can be easily performed by laser lift-off by irradiating a laser beam. (First substrate removal). Then, after removing the GaN thin film and subjecting the surface thereof to metallization, a heat sink substrate (third substrate) having good thermal conductivity and low electrical resistance is bonded in the substrate state. An example is a copper material or a molybdenum material. For the connection, a material capable of withstanding the subsequent standard soldering such as a high-temperature solder material is preferable. By bonding the heat sink substrate, the glass substrate finishes its role as a support base. The adhesive layer is peeled off by irradiating ultraviolet rays from the glass substrate side, and the glass substrate is removed. As a result, the GaN element using the heat sink material as a support base in the wafer state is completed. In this state, a thin film wafer state GaN layer is mounted on the heat sink material to form an element. After that, it is cut out by the size of the element and mounted on the mounting substrate. The sapphire substrate and glass substrate used in this process can be reused after polishing the surface.

  In this case, the heat sink substrate is made of a material having a two-layer structure of a conductive and heat conductive material and an insulating material, so that the potential of the lead frame on which the element is mounted and the substrate potential of the GaN element Can be separated from each other and the degree of freedom in circuit configuration can be increased.

In the above example, after the glass substrate was bonded, the heat sink substrate was subsequently bonded. However, after the glass substrate was bonded, the sapphire substrate was removed, and the GaN thin film was also removed as necessary. It is also possible to separate and handle the element in a state where metal is vapor-deposited (metallized) on the surface, that is, in a state where the heat sink is not bonded. In this case, the glass substrate is a support base. The elements can be separated in a wafer state and mounted on a heat sink material on a mounting board, or can be mounted on a mounting board such as a lead frame without a heat sink. After mounting on the lead frame, the glass layer on the surface can be irradiated with ultraviolet rays to remove the glass substrate.

In the above example, the case where the GaN layer is directly laminated on the sapphire substrate on which the Ga-based compound semiconductor thin film layer (second thin film) is formed as the first substrate has been described. In the case where a material having better properties is required, it is also possible to use a substrate formed by bonding single crystal silicon (Si) or single crystal silicon carbide (SiC) from a wafer state seed substrate by smart cut.

In the above case, the case of using the sapphire substrate as the first substrate has been described, but it is also possible to use a Si substrate. A GaN layer is formed on a Si substrate instead of the sapphire substrate described above to form an element, and then a glass substrate which is a second substrate is bonded. In this state, the Si substrate is thinly polished and then etched away.

  FIG. 3 discloses an embodiment of the present invention. FIG. 3A shows a state in which a GaN layer 2 having a thickness of 10 μm is formed on a surface on which a Ga-based compound semiconductor 4 is formed on a sapphire substrate 3 having a thickness of about 200 μm, which is a substrate serving as a support. FIG. 7B shows a state in which a junction gate type FET is formed in the GaN film. The gate 13 is formed of a junction, and is a known structure that cuts off and conducts current between the source 11 and the drain 12. FIG. 7C shows a state in which wiring is applied to the wiring layer 15 thereon (semiconductor element forming step). The gate electrode 23, the source electrode 21, and the drain electrode 22 are on the surface layer. A glass substrate 5 having a thickness of about 400 μm is bonded to this surface via an adhesive 6 made of a photo-releasable adhesive (first bonding step). The sapphire substrate 3 on which the junction type FET element is formed on the GaN layer 2 and the glass substrate 5 are bonded together as shown in FIG. In this state, laser light is irradiated from the surface of the sapphire substrate, gallium (Ga) is deposited by the GaN-based thin film layer 4 and the sapphire substrate 3 is peeled off (first substrate removing step), and the metallized layer 16 is formed on the exposed GaN surface. FIG. 7-e is formed. In order to peel off the Ga-based thin film layer on the sapphire substrate with laser light, a laser lift-off technique that has already started to be used for light-emitting diodes can be applied. The support base is the glass substrate 5 in the state of FIG. In this state, a heat sink substrate 7 made of a copper material plated with solder is bonded to the back surface of the GaN layer 2 on which the metal film is vapor-deposited (metallized) on the back surface, and the substrates are joined. In this state, the heat sink substrate 7 has a wafer shape and serves as a support base after this. This state is shown in FIG. In this state, ultraviolet light is irradiated from the surface of the glass substrate 5, the adhesive is peeled off, the glass substrate 5 is peeled (second substrate removing step), and the adhesive is washed away, as shown in FIG. In this state, the support base is the heat sink substrate 7. Thereafter, the element is separated and mounted on a lead frame or the like to complete the element.

  In the example shown in FIG. 3, the potential of the lead frame on which the GaN element is mounted and the GaN element can be obtained by using a material having a two-layer structure of a conductive and heat conductive material and an insulating material as the heat sink substrate. It is possible to separate the substrate potential from each other and increase the degree of freedom in circuit configuration.

FIG. 4 shows a mounting diagram of this element. FIG. 4A shows a state in which an element in which a heat sink and a GaN element are integrated is mounted on a lead frame. The heat sink and the element are integrated, the heat sink is bonded to the lead frame, and in this state, resin molding is performed with a mold to complete the package. FIG. 4B is a cross-sectional view when the lead frame substrate 7 includes a heat sink conductive material portion 8 and a heat sink insulating material portion 9.

  FIG. 5 shows another embodiment of the present invention. The difference from FIG. 3 is that the heat sink substrate 7 is not bonded in the substrate state, the semiconductor substrate is separated in the state where the glass substrate 5 is a support base, and the state shown in FIG. It mounts on the heat sink (not shown) formed on it, and removes the glass substrate 5 after that. Manufacturing proceeds in the same manner as in FIG. 3, and the state shown in FIG. 5-f is the same as the state corresponding to FIG. In this case, the elements are individually separated in the state shown in FIG. 5-f and mounted on a heat sink provided on the lead frame.

  In FIG. 5, the heat sink substrate 7 is shown as an example of a single layer, but the heat sink substrate 7 can also have a two-layer structure of a heat sink conductive material portion and a heat sink insulating material portion. In this case, the substrate potential of the element can be separated from the potential of the lead frame on which the element is mounted.

  FIG. 6 shows a state where the elements are individually separated in the state shown in FIG. 5-f and mounted on a heat sink provided in the lead frame. FIG. 6A shows a state in which the GaN element support is mounted on the heat sink 40 on the lead frame 33 in the state of the glass substrate 5. By irradiating ultraviolet light from the surface in this state, the adhesive resin 6 can be peeled off and the glass substrate 5 can be peeled off. Thereafter, the adhesive on the surface is removed, washed, and then wire bonded, as shown in FIG. 6B. After that, packaging is performed to complete the semiconductor device. FIG. 6C shows a view in which the heat sink 40 is not a single layer of conductive material but a heat sink conductive material portion 41 and a heat sink insulating material portion 42.

  3 and 5, the GaN film forming the GaN element is a thin film of about 10 μm, which is too thin to handle by itself. In the series of steps of bonding to the heat sink substrate of the final target substrate by repeated bonding and peeling, the amount of GaN layer used is minimized, and the heat sink is not separated into elements in the wafer state. Forming is a breakthrough

  3 and 5 show an example in which a sapphire substrate is used as the base substrate and a glass substrate is used as the second substrate, but various combinations of other substrate materials are possible.

In the above example, the case where the GaN layer is directly laminated on the sapphire substrate on which the Ga-based compound semiconductor thin film layer (second thin film) is formed as the first substrate has been described. In the case where a material having better properties is required, it is also possible to use a substrate in which a Si layer or SiC layer is formed as a seed substrate by bonding a thin crystal layer from the seed substrate by smart cut (registered trademark). FIG. 7 shows the manufacturing process. FIG. 7A shows a state in which a high concentration layer (smart cut layer) 52 of hydrogen (H) ions is provided at a depth of about 0.5 μm on the surface of the Si crystal 51 of the wafer state seed crystal. FIG. 7B shows a state in which the Ga-based thin film layer 4 is formed on the sapphire substrate 3 and its surface is bonded to the Si substrate 51. By raising the temperature in this state, cleavage occurs in the smart cut layer 52, and the Si seed thin film layer 53 is peeled off. FIG. 7C shows a state where the Si seed thin film layer 53 on which the smart cut layer is formed and the sapphire substrate are bonded together. The Si surface is polished, and this is a state in which a Si layer with good crystallinity is formed on a sapphire substrate, and this becomes a substrate for forming a GaN layer thereon.

  In the above example, an Si substrate is used as a seed substrate. However, an SiC thin film can be similarly formed on a sapphire substrate using an SiC substrate as a material having a lattice constant close to that of GaN. This is exactly the same as the manufacturing process of FIG.

  In the examples from FIG. 3 to FIG. 7, the example in which the sapphire substrate is used as the first substrate has been described, but a Si substrate can also be used. A GaN layer is formed on a Si substrate instead of the sapphire substrate described above to form a junction FET element and a wiring layer, and then a glass substrate which is a second substrate is bonded. In this state, it is possible to polish the Si substrate thinly and then remove it by etching. FIG. 8 shows an example of the manufacturing process. FIG. 8 discloses an embodiment of the present invention. FIG. 8A shows a state in which a GaN layer 2 having a thickness of 10 μm is formed on the surface of a Si substrate 10 having a thickness of about 400 μm which is a substrate serving as a support. FIG. 8B shows a state in which a junction gate type FET is formed in the GaN layer. The gate 13 is formed of a junction, and is a known structure that cuts off and conducts current between the source 11 and the drain 12. FIG. 8C shows a state in which wiring is applied to the wiring layer 15 thereon (semiconductor element forming step). The gate electrode 23, the source electrode 21, and the drain electrode 22 are on the surface layer. A glass substrate 5 having a thickness of about 400 μm is bonded to this surface via an adhesive 6 made of a photo-releasable adhesive (first bonding step). FIG. 7D shows the Si substrate 10 on which the junction FET element is formed on the GaN layer 2 and the glass substrate 5 are bonded together. In this state, the Si thickness is reduced by polishing from the back surface of the Si substrate 10 and finally removed by chemical polishing (first substrate removing step), and the metallized layer 16 is formed of a metal film on the exposed GaN surface. FIG. 8-e. In this state, the heat sink substrate 7 made of a copper material solder-plated on the back surface of the GaN metallized on the back surface is bonded and bonded. In this state, the heat sink substrate has a wafer shape and serves as a support base after this. This state is shown in FIG. In this state, ultraviolet light is irradiated from the surface of the glass substrate 52, the adhesive is peeled off, the glass substrate is peeled off (second substrate removing step), and the adhesive is washed away, as shown in FIG. In this state, the support base is the heat sink 7. Thereafter, the element is separated and mounted on a lead frame or the like to complete the element.

  In FIG. 8, if the heat sink substrate 7 is made of a material having a two-layer structure of a conductive and heat conductive material and an insulating material, the potential of the lead frame on which the device is mounted, the substrate potential of the GaN device, and Can be separated, and a structure with an increased degree of freedom in circuit configuration can be obtained.

  As shown in FIG. 5 in the case of the sci-fi substrate, in the case of FIG. 8 as well, the heat sink material is not bonded in the substrate state, and the state shown in FIG. It is also possible to separate the semiconductor elements, mount each element on a heat sink, and then remove the glass substrate 5.

  The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the present invention depending on the purpose and application.

Industrial applicability

  Power-based compound semiconductor devices using GaN are becoming increasingly important with the spread of hybrid vehicles and electric vehicles. In addition, with the spread of smart grids, the role of power-based compound semiconductor devices is becoming important for household appliances and for energy management. According to the present invention, the amount of GaN, which is an expensive material, can be greatly reduced, the temperature of the element portion of the GaN element can be suppressed and a stable operation can be performed, and an inexpensive GaN semiconductor device can be manufactured. It becomes possible. This greatly contributes to the popularization of power compound semiconductor devices in this field.

DESCRIPTION OF SYMBOLS 1 ... Si substrate 2 ... GaN layer 3 ... Sapphire substrate 4 ... Ga-type thin film layer 5 ... Glass substrate 6 ... Photo-peeling adhesive 7 ... Heat sink substrate 8 ... Heat sink conductive material portion 9 ... heat sink insulating portion 10 ... silicon substrate 11 ... source 12 ... drain 13 ... gate 14 ... depletion layer 15 ... wiring layer 16 ... Metallized layer 21 ... Source electrode 22 ... Drain electrode 23 ... Gate electrode 31 ... Source part of lead frame 32 ... Drain part 33 of lead frame ... Element support part 34 of lead frame ··· Wire 40 ··· Heat sink 41 ··· Conductive material portion of heat sink 42 · · · Insulating material portion 51 of heat sink ··· Si substrate 52 ··· Smart cut layer 53 ··· Seed Thin film layer

Claims (11)

A method of manufacturing a semiconductor device using a first compound semiconductor,
The first base substrate or the substrate formed by forming the second compound semiconductor layer on the surface of the base substrate or the substrate formed by forming the third compound semiconductor layer on the surface of the base substrate is used as the first substrate, Forming a first compound semiconductor on the surface of the first substrate;
Forming a semiconductor element by forming at least one of a P-type region and an N-type region in the first compound semiconductor layer and forming an electrode; and
A first bonding step of bonding the surface of the semiconductor element formed by the semiconductor element formation step and the surface of the second substrate;
A first substrate removing step of removing the first substrate after the first bonding step;
A second substrate removing step of bonding the surface from which the first substrate has been removed by the first substrate removing step and a third substrate, and then removing the second substrate;
A method for manufacturing a semiconductor device, comprising:   2. The method of manufacturing a semiconductor device according to claim 1, wherein in the second substrate removing step, the second substrate is removed after the semiconductor element is separated and mounted on a mounting substrate.   The method for manufacturing a semiconductor device according to claim 1, wherein the base substrate is a sapphire substrate, and the second compound semiconductor is a Ga-based compound semiconductor.     4. The method of manufacturing a semiconductor device according to claim 3, wherein the first substrate removing step removes the first substrate by irradiating a surface of the sapphire substrate on which the Ga-based compound semiconductor is formed with laser light.   The method for manufacturing a semiconductor device according to claim 1, wherein the base substrate is a silicon substrate.     6. The method of manufacturing a semiconductor device according to claim 5, wherein in the first substrate removing step, the silicon substrate is thinned, and thereafter the silicon substrate is removed or the first substrate is removed by chemical etching in a final stage of thinning. . The second substrate is transparent glass;
In the second bonding step, an adhesive layer using a material that is peeled by light is formed on the surface of the semiconductor element, and then bonded to the surface of the first substrate via the adhesive layer.
The second substrate removing step removes the second substrate by irradiating with light.
A method for manufacturing a semiconductor device according to claim 1.   The method of manufacturing a semiconductor device according to claim 1, wherein the first compound semiconductor is gallium nitride GaN.   The method for manufacturing a semiconductor device according to claim 1, wherein the third compound semiconductor is silicon carbide SiC.   The method for manufacturing a semiconductor device according to claim 1, wherein the third substrate is a heat sink material.   The method for manufacturing a semiconductor device according to claim 1, wherein the third substrate is a substrate material having a two-layer structure of a conductive heat sink material and an insulating material.

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