JP3114320B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a device structure and a method for manufacturing a pressure contact type gate turn-off thyristor.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device such as a press-contact type gate turn-off thyristor, a heat buffer plate such as tungsten or molybdenum is attached to an anode electrode by a brazing method. In this bonding method by brazing, when applying the passivation rubber to the bevel portion of the semiconductor element, the heat buffer plate brazed plays a role of damping the flowable passivation rubber, so that the bevel portion can be easily passivated. There is an advantage that the heat buffer plate can be positioned relatively easily.

However, the method of forming an anode electrode by the above-mentioned alloy method has a problem in that warpage of the element and thermal fatigue of the cathode electrode occur due to a difference in thermal expansion coefficient between the semiconductor element and the thermal buffer plate. It is necessary to take measures such as thickening the plate and arranging the cathode emitters radially.

[0004] As a result, the use of expensive thermal buffer plates increases, which is a major cause of cost increase. Furthermore, the radial arrangement of the cathode emitters is geometrically inefficient in the area of the element, so that a large current of the element is required. This is a disadvantageous configuration.

Further, the use of the alloy causes the alloy surface of the semiconductor element, which is the anode emitter side, to be eroded by 10 μm or more, so that the characteristics of the element become uneven and the diffusion layer on the anode emitter side is formed too deep. There is also the problem of having to do so.

Therefore, in recent years, a method (alloy-free method) of bonding to a semiconductor element by pressure welding without brazing the heat buffer plate has been performed. The alloy-free method is superior in reliability and cost as compared with the alloy method. FIG. 9 shows an element having a structure in which the heat buffer plate is not brazed (hereinafter, referred to as an alloy-free element).

However, in the conventional brazed element, when the bevel portion is coated with the passivation rubber, the brazed thermal buffer plate prevents the rubber from flowing down.
In this alloy-free element, it is difficult to prevent the rubber from flowing out.

[0008] Further, in the alloy-free element, it is required to make the press contact stress more uniform than in the conventional brazing element. Therefore, it is necessary to precisely position both heat buffer plates.

Therefore, as shown in FIG. 9, in the alloy-free device, a polyimide film 11 is formed on the bevel surface,
Around the transfer mold resin 12 as shown in the figure.
The formation of the rubber prevents outflow of the passivation rubber.

In FIG. 9, since the position of the transfer mold resin 12 and the shape of the transfer mold resin 12 can be controlled, as shown in FIG.
7 is performed.

Further, similarly to the thermal buffer plate, the position of the silicon wafer 4 is determined using the wall of the transfer mold resin 12. However, if the diameters of the pressure contact surfaces of the copper blocks 1 and 8 are equal to the diameter of the heat buffer plate, there is a possibility that the pressure contact becomes uneven. Therefore, as shown in the figure, one of the pressure contact surfaces of the copper block is made smaller than the heat buffer plate. I have.

[0012]

However, the transfer molding resin molding apparatus is expensive, so that a large capital investment is required for molding the transfer molding resin.

Further, in order to use the transfer mold resin for positioning the thermal buffer plate and for positioning the silicon wafer, it is necessary to form the transfer mold resin with high accuracy and to position the silicon wafer accurately. Therefore, in order to increase the molding accuracy, a larger capital investment is required.

Furthermore, in order to position the silicon wafer on the inner peripheral wall of the transfer mold resin having the same diameter as the thermal buffer plate as described above, it is necessary to make the outer diameter of the copper block larger than that of the conventional brazing element. . Therefore, the cost of the copper block and the weight of the element are increased.

SUMMARY OF THE INVENTION The present invention has been made under the above background, and enables easy and accurate positioning of members such as a semiconductor substrate and a thermal buffer plate, and is economically advantageous in manufacturing a semiconductor device. The aim is to provide a method.

[0016]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a tubular member having a flange inside, by coating a non-flowable passivation material inside the opening end of the flange. Positioning a thermal buffer plate on the main surface of the semiconductor substrate,
The heat buffer plate is positioned so that at least a portion of the heat buffer plate is inserted into the open end of the flange of the tubular member, with the open end of the flange of the tubular member serving as a guide. The semiconductor substrate is placed on the non-flowable passivation material applied to the inside of the opening end of the flange portion of the cylindrical member to position the semiconductor substrate and the cylindrical member. Performing a pressure contact between the semiconductor substrate and the heat buffer plate after pouring a flowable passivation material into a gap formed between the semiconductor substrate and the cylindrical member having the flange portion and curing the semiconductor substrate. I do.

In the method of manufacturing a semiconductor device, when the cylindrical member and the semiconductor base are positioned,
The open end of the flange of the cylindrical member has a protruding portion that protrudes from a heat buffer plate inserted into the open end of the flange of the cylindrical member, and has a cylindrical shape including the semiconductor base and the flange. After pouring a flowable passivation material into the gap formed between the cylindrical member and the hardening member, the cylindrical member fixed to the heat buffer plate and the semiconductor substrate is guided by the opening end protrusion of the flange of the cylindrical member as a guide. A method of manufacturing a semiconductor element, comprising positioning the tubular member and the metal block by inserting the member into the metal block, and thereafter performing pressure welding of the metal block, the heat buffer plate, and the semiconductor base. Provided.

Further, after a flowable passivation material is poured into a gap formed between the semiconductor substrate and the cylindrical member having the flange portion and hardened, an outer edge of the cylindrical portion of the cylindrical member is guided. By positioning this element case and the cylindrical member by inserting it into the element case,
Thereafter, a method for manufacturing a semiconductor device, wherein the thermal buffer plate and the semiconductor substrate are pressed against each other is also provided.

Further, in the above-described method for manufacturing a semiconductor device, the method further comprises: flowing a flowable passivation material into a gap formed between the semiconductor substrate and the cylindrical member having the flange portion; After inserting the heat buffer plate at the opening end of the ring-shaped member that can be inserted with the inner edge of the cylindrical portion of the cylindrical member as a guide on the main surface of the base opposite to the main surface to which the heat buffer plate is fixed. A method for manufacturing a semiconductor device is also provided, wherein the ring-shaped member is inserted into the opening end of the cylindrical portion of the cylindrical member, and thereafter, the thermal buffer plate and the semiconductor substrate are pressed against each other.

As described above, by positioning the semiconductor substrate, the heat buffer plate, the metal block, and the like using the inner diameter of the flange portion of the cylindrical member and the outer diameter of the cylindrical portion of the cylindrical member as a guide, each member is formed. Are positioned with a very high degree of accuracy, so that the pressure contact stress is made uniform at the time of pressure welding, and a semiconductor element having good characteristics can be manufactured.

In addition, since the passivation process can be performed at the same time by the above method, it is most suitable for manufacturing a semiconductor device having a bevel structure.

[0022]

The present invention will be described below with reference to examples. In this embodiment, a gate turn-off thyristor having a bevel structure is used as a semiconductor element for performing passivation processing. Further, a copper block was used as the metal block.

In FIGS. 1 and 2 to 9, reference numeral 1 denotes a copper block which is one main electrode conductor brought into pressure contact with the thermal buffer plate 2, and 2 denotes molybdenum which is a material having a thermal expansion coefficient substantially equal to that of silicon. Buffer plate made of steel or tungsten,
Reference numeral 3 denotes an anode electrode made of an aluminum vapor-deposited layer and formed on one main surface of a silicon wafer 4 (semiconductor substrate).

Reference numeral 4 denotes a silicon wafer which is a semiconductor substrate having a PNPN structure, and the heat buffer plate 2 is configured to be pressed against the silicon wafer 4 via an anode electrode 3.

On the main surface of the silicon wafer 4 facing the anode electrode 3, a disk-shaped gate electrode 5 made of an aluminum vapor-deposited layer is formed.

Reference numeral 6 denotes an aluminum vapor-deposited layer,
On the main surface of the silicon wafer 4 having the gate electrode 5, the other main electrode formed around the gate electrode 5 and formed concentrically is preferably a plurality of cathode electrodes. A ring-shaped thermal buffer plate 7 made of a material having substantially the same thermal expansion coefficient is formed.

Reference numeral 8 denotes a cathode copper block which is the other main electrode conductor which is brought into pressure contact with the thermal buffer plate 7, 9 is a gate post which is brought into pressure contact with the gate electrode 5 and is connected to an external electrode, and 10 is a gate post. A ceramic part 13 that forms the outer peripheral part of the case of the element is an insulating ring made of a tubular member having a flange inside.

In this embodiment, as shown in FIG. 1, a passivation material is applied to the inside of the opening end of the above-mentioned flange portion of the insulating ring 13A, and then, preferably, the semiconductor element is subjected to bevel processing to remove processing distortion. Is inserted into the insulating ring 13A and placed on the previously applied passivation material.

Next, a passivation process is performed by pouring a fluid passivation material into a gap formed between the semiconductor element and the cylindrical member and curing the material. Hereinafter, the passivation method and the method of press-contacting a semiconductor element will be described with reference to FIG.

First, the concentric heat buffer plate 7 is placed on the concentric cathode electrode 6 and positioned. Since this positioning is performed between concentric circles, an accuracy of about ± 100 μm can be easily obtained visually without using an expensive device.

Next, an insulating ring 13A having an outer wall substantially equal to the outer edge of the heat buffer plate 7 and not exceeding the size of the outer edge is inserted into the heat buffer plate 7 using the inner peripheral wall as a guide and positioned. . Therefore, there is almost no play between the insulating ring 13A and the heat buffer plate 7, and the positioning of the insulating ring 13A and the heat buffer plate 7 can be performed accurately and easily.

Thereafter, the bevel portion is protected by applying and curing the non-flowable rubbers 14 and 15 and the flowable passivation rubber 16.

Further, the heat buffer plate 2 is placed on the anode electrode 3 and is positioned in the same manner as the heat buffer plate 7.
7 is fixed by applying and curing. The non-flowable rubber 17 may not be applied. In this case, the non-fluid rubber 15 used for protecting the bevel portion also serves to fix the thermal buffer plate 2.

Further, on the side of the inner edge of the flange portion of the insulating ring 13A facing the thermal buffer plate 7, a projecting portion which is substantially equal to the shape of the outer edge of the cathode side copper block 8 and which projects in the direction opposite to the semiconductor substrate is provided. As shown in FIG. 1, the components are separately provided and the above-mentioned bonded components are assembled in a case.

In FIG. 1, since the copper block 8 is smaller than the heat buffer plate 7, the inner diameter of the protruding portion is smaller than the diameter of the flange portion on the semiconductor substrate side.
The diameter of this protrusion may be equal to or larger than the diameter of the flange on the semiconductor substrate side in accordance with the size of the protrusion.

The shapes of the copper blocks 1 and 8, the thermal buffer plates 2 and 7, the semiconductor substrate 4, and the like are not particularly limited, but are preferably circular or ring-shaped.

As a result, the insulating ring 13A and the copper block 8 can be positioned with high accuracy, as in the case of positioning the thermal buffer plate 7.

Since the copper block 8 and the copper block 1 can be easily positioned, if the insulating ring 7 having the silicon wafer 4 and the thermal buffer plate 7 is positioned with respect to the copper block 8, the copper block 8 Similarly, it is possible to easily position the block 1 with high accuracy.

Hereinafter, the anode electrode 2 and the cathode electrode 6
An example of a method of positioning and positioning the silicon wafer 4 (semiconductor substrate) having the above, the thermal buffer plate 7, and the insulating ring 13 will be described.

(A) As shown in FIG. 2A, first, a heat buffer plate 7 which is thicker than usual is positioned on the cathode electrode 6, and a non-fluid rubber 20 is applied and cured to be positioned. At this time, preferably, the non-flowable rubber 20 is prevented from adhering from half the thickness of the thermal buffer plate 7 to above.

Next, as shown in FIG.
A non-fluid rubber 14 is applied to the flange portion of A, and is adhered to the silicon wafer 4 with the positioned thermal buffer plate 7 as a guide. At this time, preferably, the insulating ring 1 is set so that the cured non-fluid rubber 20 does not contact the insulating ring 13A.
Make a recess in the flange of 3A. Therefore, in this case, the inner periphery of the flange portion of the insulating ring prevents the small diameter portion having substantially the same shape as the cathode copper block 8, the middle diameter portion having substantially the same shape as the heat buffer plate 7, and the non-fluid rubber 20 from contacting with each other. It has a stepped shape having a large diameter portion.

Thereafter, in order to prevent the rubber from flowing into the anode electrode 3, a wall of a non-flowable rubber 15 is formed on the anode surface as shown in FIG. 2c, and a flowable passivation rubber 16 is poured on the bevel surface and cured. .

(B) As shown in FIG. 3A, a step is provided at the outer edge of the thermal buffer plate 7 so that the outer edge has a shape substantially equal to the shape of the cathode copper block 8, and the large-diameter side of the outer edge is connected to the cathode electrode 6. The positioning is performed by the non-flowable rubber 20 similarly to the first embodiment.

Next, as shown in FIG.
The non-fluid rubber 14 is applied to the flange of 3A, and is adhered to the silicon wafer 4 with the positioned heat buffer plate 7 as a guide. At this time, a step is provided in advance on the inner periphery of the flange portion side of the insulating ring 13A, and its small diameter is almost equal to the small diameter of the heat buffer plate 7 and the large diameter is set so as not to bite the hardened non-fluid rubber 20. Adjust the diameter.

Thereafter, as shown in FIG. 3c, a wall of non-fluid rubber 15 is formed on the anode surface to prevent the rubber from flowing into the anode electrode 3, and a flowable passivation rubber 16 is poured on the bevel surface and cured. .

(C) As shown in FIG. 4A, the thermal buffer plate 7 is positioned on the cathode electrode 6, and the non-fluid rubber 20 is applied to the inner diameter side surface of the thermal buffer plate and cured to be positioned. .

Next, as shown in FIG.
The insulating ring 13A having the adhesive surface 4 applied to the bonding surface is bonded to the silicon wafer 4 using the positioned thermal buffer plate 7 as a guide. At this time, a step is provided in advance on the inner periphery of the flange portion side of the insulating ring 13A, and its small diameter is made substantially equal to the cathode copper block, and its large diameter is made equal to the diameter of the thermal buffer plate 7. Thereafter, as shown in FIG. 4c, a wall of non-flowable rubber 15 is formed on the anode surface to prevent the rubber from flowing into the anode electrode 3, and the flowable passivation rubber 1 is formed on the bevel surface.
Pour 6 and cure.

(D) In FIG. 5A, the silicon wafer 4
Is placed on the support jig 21, and the thermal buffer plate 7 is positioned above the cathode electrode 6.

Next, with the silicon wafer 4 placed on the support jig 21, an insulating ring 13A as shown in FIG. And adhere to the pellet. The small diameter of the insulating ring 13A is substantially equal to that of the cathode copper block 8, and the large diameter thereof is substantially equal to that of the heat buffer plate 7. In addition, in order to enhance the adhesiveness with the non-fluid rubber 14, the non-fluid rubber 14 A recess is made in advance in the contact portion with.

At this time, since the heat buffer plate 7 is not fixed, care should be taken not to shift it. Thereafter, the non-flowable rubber is cured while being placed on the support jig. Thereby, the heat buffer plate 7 and the insulating ring 13A are fixed at the same time.

Thereafter, in order to prevent the rubber from flowing into the anode electrode 3, a wall of the non-flowable rubber 15 is formed on the anode surface, and the flowable passivation rubber 16 is poured into the bevel surface and hardened.

After fixing the thermal buffer plate 2, the silicon wafer 4 having the anode electrode 3, the gate electrode 5, and the cathode electrode 6 and the insulating ring 13A by the above-described methods,
Cathode copper block 8 at flange of insulating ring 13
By using the inner wall portion corresponding to the outer diameter shape as a guide, the thermal buffer plate 2, the silicon wafer 4 having the anode electrode 3, the gate electrode 5, the cathode electrode 6, and the insulating ring 13A can be accurately positioned.

In the above method, the position of the cathode copper block 8 is determined by using the shape of the inner edge of the flange of the insulating ring 13, but the position of the cathode copper block 8 is determined by using the shape of the outer edge of the cylindrical portion of the insulating ring. 8 can also be located. The method is described below. (E) As shown in FIG. 6, in this example, the positioning of the insulating ring 13B is performed by controlling the maximum outer diameter of the silicon wafer 4, and the positioning of the silicon wafer 4 with respect to the cathode copper block 8 is insulated. Ring 13B
And the shape of the inner edge of the ceramic portion 10 of the case. Therefore, in this embodiment, it is also possible not to provide the above-mentioned projection on the flange of the insulating ring.

Further, in the above embodiment, one insulating ring is used. However, positioning can be performed by using a plurality of insulating rings. The method is described below.

(F) As shown in FIG. 7, another insulating ring 19 is combined with the insulating ring 13A, and the inner diameter of the insulating ring 19 is adjusted in advance to position and fix the heat buffer plate 2 on the anode side. Is made possible.

(G) As shown in FIG.
By making the inner diameter of A approximately equal to that of the cathode copper block 8, the positioning and fixing of the insulating ring 13A are performed by the cathode copper block 8.

At this time, one end of the insulating ring is made to protrude from the lower end of the cathode copper block 8, and this protruding portion is
The position of the heat buffer plate 7 and the position of the silicon wafer 4 with respect to the copper block are determined by contacting the outer edge of the silicon wafer 4. In the drawing, the position on the cathode side can also be determined by combining another insulating ring 19 using the same method as in the sixth embodiment.

After positioning of each member by the above-described methods, pressure contact is performed to complete a semiconductor element.

In each of the above examples, the non-fluid rubber 15
Alternatively, the outflow of the passivation rubber may be prevented by another member or means.

The plurality of insulating rings 13 and 19
In the example using the insulating ring, an insulating ring having a shape in which the insulating ring 19 is integrated with the insulating ring 13 in advance may be used alone.

As described above, the present invention is suitable for a passivation processing method and a positioning method for a semiconductor element.
Manufacture of preferably a gate turn-off thyristor, a diode, a thyristor, an electrostatic induction thyristor, an IGBT (insulated-gate bipolar transistor), a thyristor with an insulated gate, etc., which are semiconductor elements connected to external electrodes by pressure welding similarly to the gate turn-off thyristor. Suitable for the method.

In particular, a gate turn-off thyristor has a main electrode on each of both main surfaces of a semiconductor substrate, and a cathode electrode, which is a cathode electrode as one of the main electrodes, is surrounded by the gate electrode and dispersed on the main surface. The two main electrodes are connected to the external electrodes by pressure welding via a thermal buffer plate not brazed to silicon such as molybdenum or tungsten, which is a material having a thermal expansion coefficient almost equal to that of silicon, and the gate electrode is pressed to the vicinity of the element center. It is preferable to use a structure that is connected to an external electrode by the provided gate lead.

The end face of the semiconductor portion of the gate turn-off thyristor is preferably so-called beveled so that an electric field at the end face is weakened.

Further, the passivation of the beveled surface is preferably performed as follows.

(1) The main surface of the semiconductor substrate including the anode electrode 3, the silicon wafer 4, the gate electrode 5, the cathode electrode 6, and the heat buffer plate having the heat buffer plate 7, and the flange of the insulating ring 13. The parts are adhered by the passivation rubber 14 without any gap.

(2) Then, a wall of the non-flowable passivation rubber 15 is formed at the end of the other surface so that the flowable passivation rubber 16 does not flow into the main surface on the anode electrode side of the semiconductor substrate.

(3) Fluid passivation rubber is poured into the groove formed by the beveled surface of the semiconductor substrate and the insulating ring 13 to such an extent that the bevel surface is completely covered. Thereafter, the non-flowable passivation rubbers 14 and 15 are poured. And the flowable passivation rubber 16 is cured.

This semiconductor positioning method is performed as follows.

(1) The semiconductor substrate is positioned and fixed to the insulating ring by inserting the insulating ring 13 into the heat buffer plate 7 on the cathode electrode side which has been positioned in advance. (2) Positioning is performed by bringing the insulating ring 13 into contact with the cathode copper block 8.

At this time, it is assumed that the shape of the inner edge of the flange of the insulating and insulating ring 13 can be positioned by bringing it into contact with the cathode copper block.

After positioning and positioning each member as described above, pressure contact is performed to manufacture a semiconductor element.

In the above method for manufacturing a semiconductor device,
The heat buffer plate 2 on the anode side is fixed by the insulating ring 13.
Further, it is also possible to carry out by using the inner peripheral wall of the insulating ring 19 adhered from the anode side.

It is also possible to position and fix the insulating ring 13 by bringing it into contact with the heat buffer plate 2 on the anode electrode side previously positioned.
Further, the insulating ring 13 is positioned and fixed on the silicon wafer 4 without using the heat buffer plate 7 on the cathode electrode side, and the silicon wafer for the cathode electrode side heat buffer plate and the copper block is brought into contact with the inner peripheral wall of the insulating ring 13. By doing so, it is also possible to perform positioning.

[0074]

According to the present invention, since the semiconductor element is manufactured as described above, the bevel portion is subjected to the passivation processing and the position of the heat buffer plate pressed against the main electrode without using expensive manufacturing equipment. , And precise positioning of a silicon wafer as a semiconductor substrate in the element case is possible.

Further, since the outer diameter of the metal block such as the copper block may be the same as that of the conventional brazing element, it is not necessary to newly manufacture a member such as the metal block, which is economically advantageous.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for positioning a base according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a method of positioning a base according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram of a method for positioning a base according to one embodiment of the present invention.

FIG. 4 is an explanatory view of a method for positioning a base according to one embodiment of the present invention.

FIG. 5 is an explanatory view of a method for positioning a base according to one embodiment of the present invention.

FIG. 6 is an explanatory view of a method of positioning a base according to one embodiment of the present invention.

FIG. 7 is an explanatory diagram of a method of positioning a base according to one embodiment of the present invention.

FIG. 8 is an explanatory view of a method for positioning a substrate according to one embodiment of the present invention.

FIG. 9 is an explanatory view of a conventional method of positioning a base.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Copper block 2 ... Heat buffer plate 3 ... Anode electrode 4 ... Silicon wafer 5 ... Gate electrode 6 ... Cathode electrode 7 ... Heat buffer plate 8 ... Cathode copper block 9 ... Gate post 10 ... Ceramic part 11 ... Polyimide 12 ... Transfer mold Resin 13A: insulating ring 13B: insulating ring 14, 15: non-flowable rubber 16: flowable passivation rubber 17, 18: non-flowable rubber 19: insulating ring 20: non-flowable rubber 21: silicon wafer support jig

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 29/74 H01L 23/02 H01L 23/10 H01L 23/36

Claims (4)

(57) [Claims] 1. A non-fluid passivation material is applied to the inside of an opening end of the flange of a cylindrical member having a flange inside, and a heat buffer plate is positioned on a main surface of a semiconductor substrate. The heat buffer plate was positioned so that at least a part of the heat buffer plate was inserted into the open end of the flange of the tubular member, with the open end of the flange of the tubular member serving as a guide. The semiconductor substrate is allowed to stand on the non-flowable passivation material applied to the inside of the opening end of the flange portion of the cylindrical member to position the semiconductor substrate and the cylindrical member. The method according to the present invention is characterized in that a fluid passivation material is poured into a gap formed between the semiconductor substrate and the cylindrical member having the flange portion, and is cured, and then the thermal buffer plate and the semiconductor substrate are pressed against each other. A method for manufacturing a semiconductor device. 2. The method of manufacturing a semiconductor device according to claim 1, wherein when the cylindrical member and the semiconductor substrate are positioned, an opening end of the flange of the cylindrical member is formed by a flange of the cylindrical member. A protrusion protruding in a direction facing the semiconductor base with respect to the heat buffer plate inserted into the opening end of the base, and a gap formed between the semiconductor base and the cylindrical member having the flange After the flowable passivation material is poured into and cured, the cylindrical member fixed to the heat buffer plate and the semiconductor substrate is inserted into the metal block using the opening end protrusion of the flange of the cylindrical member as a guide. A method for manufacturing a semiconductor device, comprising: positioning the cylindrical member and the metal block; and thereafter, pressing the metal block, the thermal buffer plate, and the semiconductor substrate. 3. The method of manufacturing a semiconductor device according to claim 1, wherein a flowable passivation material is poured into a gap formed between the semiconductor substrate and the cylindrical member having the flange portion, and is cured. Positioning the element case and the cylindrical member by inserting the outer edge of the cylindrical portion of the cylindrical member into the element case as a guide, and then performing pressure contact between the thermal buffer plate and the semiconductor substrate. Semiconductor device manufacturing method. 4. The method for manufacturing a semiconductor device according to claim 1, wherein a flowable passivation material is poured into a gap formed between the semiconductor substrate and the cylindrical member having the flange. After curing, heat is applied to the opening end of the ring-shaped member, which can be inserted into the main surface of the semiconductor substrate opposite to the main surface to which the thermal buffer plate is fixed, using the inner edge of the cylindrical portion of the cylindrical member as a guide. After the buffer plate is inserted, the ring-shaped member is inserted into the opening end of the cylindrical portion of the cylindrical member, and thereafter, the thermal buffer plate and the semiconductor substrate are pressed against each other. Method.