JP2748304B2 - Method of manufacturing press-contact type semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to a method for manufacturing a semiconductor device to be insulated and, in particular, a press-contact type semiconductor device in which defects associated with a jig are improved.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional pressure contact type semiconductor device (hereinafter simply referred to as "semiconductor device") is an insulating device formed so as to cover a semiconductor substrate 11 and a bevel end surface 12 on the outer periphery thereof over the entire circumference. A surface insulating structure including the member 13 is used. The insulating member 13 also has a purpose of protecting the semiconductor substrate 11 and needs to be made of a material rich in rubber elasticity. Further, the insulating member 13 is formed by applying an insulating resin, which is characterized by having extremely high adhesion to the semiconductor substrate 11 and being extremely excellent in moisture resistance or heat resistance, to the bevel end surface 12 of the semiconductor substrate 11. A multilayer structure in which an insulating member rich in rubber elasticity is formed after being formed is often used.

Next, an example of a manufacturing process for obtaining an example of the conventional structure shown in FIG. 4 will be described with reference to FIG. FIG. 5 is a front cross-sectional view showing one example, and a step of preparing a semiconductor substrate 11 having at least one bonding surface between semiconductor layers of different conductivity types is first performed. Next, the semiconductor substrate 11 is sandwiched between two jigs 14 and 15 from above and
Is placed on the upper jig 14 to set the semiconductor substrate 11. The purpose of placing the weight 16 on the upper jig 14 is that the semiconductor substrate 11, the upper and lower jigs 14,
Because it is to prevent the insulating resin injected in the next step from leaking from the joint between the parts by improving the contact between the three members of 15, it is not necessarily a method of putting the weight 16, for example, A method of tightening with screws from above and below may be used at all. Then, a step of injecting a liquid insulating member from an injection hole 14a provided in the upper jig 14 and a step of curing the injected insulating member to integrate the insulating member 13 with the semiconductor substrate 11 are sequentially performed. Do. Then, the semiconductor substrate 11
Jigs 14 and 15
Then, the structure example of the conventional pressure contact type semiconductor device shown in FIG. 4 is obtained. In the step of removing the semiconductor substrate 11 from the jigs 14 and 15, a force higher than the frictional force existing between the insulating member 13 and the surface 15a of the jig 15 must be applied to the semiconductor element from above and below. However, since a material such as a thermosetting silicone rubber generally used as a material of the insulating member 13 has high adhesiveness to other substances, a friction existing between the insulating member 13 and the surface 15a of the jig 15 is present. The force becomes very large, and accordingly, the vertical force applied to the semiconductor element in the removal process becomes very large.

[0004]

However, in the conventional structure shown in FIG. 4, after the insulating member 13 is formed, the semiconductor element formed by integrating the semiconductor substrate 11 and the insulating member 13 is shown in FIG.
The step of removing from the jig 15 shown in FIG. Generally, the adhesion between the insulating member 13 and the jig 15 is often high,
When removing this semiconductor element from the jig 15, the surface of the jig 15
The frictional force at 15a becomes very large, and the vertical force applied to the semiconductor element at the time of taking out also becomes large and the semiconductor element is distorted, so that the insulating member 13 is cracked or the semiconductor substrate 11 is damaged. There is a risk of malfunction. For example, since a material such as a fluororesin has relatively high releasability from the insulating member 13, a method of coating the surface of the jig 15 in FIG. Although there is a method of using a material such as a resin, the above-mentioned problems are more likely to be manifested as the diameter of the semiconductor element becomes larger, and thus cannot be a complete solution. In addition, applying a release agent or the like to the surface of the jig 15 to remove the semiconductor element from the jig 15 smoothly has a high risk of contaminating the bevel end surface 12 of the semiconductor substrate 11 and has a sufficiently high reverse withstand voltage. It should be avoided because it is considered impossible to obtain the semiconductor device, and the problem existing during the process of taking out the semiconductor element from the jig 15 conventionally used remains.

[0005]

In order to achieve the object, a semiconductor substrate having at least one junction surface between semiconductor layers of different conductivity types, and an outer peripheral end face of the semiconductor substrate are formed over the entire circumference. A ring-shaped insulating device having a smaller inner diameter than the outer peripheral end surface of the semiconductor substrate in the surface insulating structure formed so as to cover the semiconductor substrate, wherein a gap between the semiconductor substrate and the insulating device is at least one layer or more. In this case, the semiconductor device is filled with the elastic insulating member so as to be bonded to each other to insulate the entire outer peripheral end face. Also, at least one or more annular grooves may be provided on the inner peripheral surface of the ring-shaped insulating device. The manufacturing process of the semiconductor element obtained in this manner includes a process of preparing the semiconductor substrate, a process of arranging the semiconductor substrate and the insulating device concentrically, sandwiching the semiconductor device with at least two or more jigs from above and below, and forming a liquid. A step of preparing to inject the insulating member, a step of injecting the liquid insulating member into an outer peripheral portion of the semiconductor substrate, and curing the injected insulating member to cure the semiconductor substrate, the insulating device, and the insulating member. And a step of separating and removing the two or more jigs sandwiching the semiconductor element and the semiconductor element. That is, in the press-contact type semiconductor device according to the present invention, an insulating device made of a material such as a less elastic fluororesin is provided on the outside of the highly elastic insulating member that covers the entire peripheral surface of the bevel end surface of the semiconductor substrate. The added FW structure (flat wafer structure) was adopted, and a method of providing a concave portion or a convex portion on the inner wall of the outermost insulating device was adopted.

[0006]

The semiconductor device, the insulating member having high elasticity and the insulating member having low elasticity at the outermost periphery are integrated by adding an insulating device to the outermost peripheral portion of the element. In the step of taking out the semiconductor element from the jig, the semiconductor element can be removed from the jig without applying a vertical force. As a result, the problem that has conventionally occurred during the step of removing the element from the jig does not occur, and the yield can be significantly improved.

In general, an insulating device having low elasticity has high adhesion to other substances, and the insulating device having low elasticity on the outermost periphery is detached from the semiconductor element when handling the semiconductor device. Although there is little danger of damaging the insulating member and the semiconductor substrate, the presence of the concave or convex portions provided on the inner wall of the insulating device with low elasticity allows the insulating device with low elasticity and the insulating member with high elasticity as a whole. Good adhesion over the entire surface, there is almost no danger that the insulating device with low elasticity will separate from the semiconductor device and damage the insulating member with high elasticity and the semiconductor substrate when handling the semiconductor device. improves. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0008]

FIG. 1 is a structural view showing one embodiment of a pressure contact type semiconductor device to which an FW structure is applied. In FIG. 1, reference numeral 1 denotes a semiconductor substrate, which may be any semiconductor material such as Si, SiC, or GaAs, and may be any of various diodes, transistors, or thyristors. In any case, the pressure contact type semiconductor element is often used for high power. In this case, in particular, a high withstand voltage is ensured by forming a bevel end surface 1a with an inclined end surface of the semiconductor substrate 1 where the pn junction is exposed. doing. Outside the bevel end face 1a, an insulating member 2 is formed so as to cover the bevel end face 1a over the entire circumference for both the purpose of protecting the bevel end face 1a and the purpose of ensuring a pressure resistance close to the theoretical limit value. You. The insulating member 2 needs to be made of a material that is rich in rubber elasticity and can reduce stress due to external force.
The insulating member 2 has an insulating layer formed on the bevel end face 1a, which is characterized by having extremely high adhesion to the semiconductor substrate 1 and having extremely excellent moisture resistance or heat resistance. A multilayer structure in which an insulator layer rich in rubber elasticity is formed may be used.

In the structure of the present invention, an insulating device 3 made of a material such as a fluororesin exists outside the insulating member 2. Since the insulating device 3 is not a highly elastic insulator such as silicone rubber, but an insulator having a low elasticity such as a fluororesin, the processing of the insulating device 3 is performed with higher precision, and as a result, the insulating device 3 is assembled into a seal. The center can be easily adjusted with higher precision. Further, by performing various processes on the outer wall of the insulating device 3, a shape having a large creepage length with a small volume can be obtained, and a high breakdown voltage can be achieved without impairing the effective area of the semiconductor element. It has a ripple effect.

Hereinafter, the manufacturing process of the FW structure of the present invention will be described with reference to FIG. First, a semiconductor substrate 1 having at least one bonding surface between semiconductors of different conductivity types
Is performed. Next, after positioning the semiconductor substrate 1 and the insulating device 3, the two jigs 6 and 7 are aligned.
A preparatory process for forming the insulating member 2 with the weight 9 placed on the upper jig 6 is performed. This weight 9
Is placed on the upper jig 6 by applying pressure from above and below to the semiconductor substrate 1, the insulating device 3, and the upper and lower jigs 6, 7.
This is to prevent the liquid insulating member from leaking out from the joint of the parts by improving the contact between the four members, so that it is not always necessary to put the weight 9 on, for example, tightening with screws from above and below It does not matter even if it is a method.
In addition, in order to align the semiconductor substrate 1 and the insulating device 3, a mark for alignment may be provided on the jig 6 or the jig 7, or a new jig for alignment may be added. It does not shake the gist at all and there is no problem at all.
Then, a step of injecting a liquid insulating member from an injection hole 8 provided in the upper jig 6, and curing the injected liquid insulating member so that the semiconductor substrate 1, the insulating member 2, the insulating device 3, Are sequentially performed. Thereafter, when the integrated semiconductor element is removed from the jig 6 or the jig 7, the semiconductor substrate 1, the insulating member 2, and the insulating device 3 are integrated in the structure according to the present invention. In addition to not applying a large force greater than the large frictional force existing between the surface 15a of the tool 15 and the insulating portion 13 in the vertical direction of the semiconductor element, the jigs 6, 7 Since the bonding area between any one of them and the insulating member 2 becomes small, the jigs 6 and 7
Removal of the semiconductor element from the jig is extremely easy, and the problems that have conventionally been encountered in the step of removing the semiconductor element from the jig have been almost solved.

Further, a concave portion 3a is provided on the inner wall surface of the insulating device 3, that is, on the bonding surface with the insulating member 2,
The close contact between the insulating member 3 and the insulating member 2 is improved. This prevents the insulating member 2 and the insulating device 3 from being separated from each other when handling the semiconductor element, thereby preventing the semiconductor substrate 1 and the insulating member 2 from being damaged, thereby further improving reliability. The shape of the concave portion 3a is shown in FIG.
As shown in (a) to (f), various types of shapes can be applied. That is, as a specific example, FIG.
(B) is an example of a convex shape 3b into which a wedge is driven, FIG. (C) is an example of a spherical concave shape 3c,
FIG. 4D shows an example in which neither a concave shape nor a convex shape is provided, FIG. 5E shows an example in which a rectangular projection shape 3d is provided, and FIG. 5F shows an example in which a shape 3e having wedge-shaped projections is provided.

[0012]

As described above, according to the present invention, in the step of taking out the semiconductor element from the jig, the jig can be very easily attached without applying the vertical force applied to the conventional semiconductor element. To remove the semiconductor element from the jig, which has caused cracks in the highly elastic insulating member, distorted the semiconductor substrate, and damage. Can be solved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory view showing various shapes of the insulating device of the present invention.

FIG. 3 is an explanatory view illustrating a manufacturing method for obtaining a pressure contact type semiconductor device of the present invention.

FIG. 4 is a structural diagram showing an example of the related art.

FIG. 5 is an explanatory view for explaining a manufacturing method for obtaining a conventional pressure contact type semiconductor element.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 insulating member 3 insulating device 1a bevel end surface 3a concave shape 3b concave shape 3c concave shape 3d projection shape 3e projection shape 6 jig 7 jig 8 injection hole 9 weight

Claims (3)

(57) [Claims] 1. A semiconductor device for insulatingly covering the outer periphery of a semiconductor substrate, comprising a jig, a semiconductor substrate, and an insulating device, wherein the jig is vertically integrated to be integral with each other. A hole for injecting an insulating member outside the annular protrusion and an annular protrusion at the portion to be formed, and further formed such that a space is formed in the outer peripheral portion of the semiconductor substrate when the upper and lower jigs are overlapped, The insulating device is an annular member made of a material that can be machined and has a small change in elasticity, and is disposed near the outer periphery of the semiconductor substrate so that the space is sealed when the semiconductor substrate is sandwiched by the jig. An insulation member is injected from a hole in the jig, and is cured to form an insulator closely adhered to the outer periphery of the semiconductor substrate, and an insulating device is fixed to the insulator. Mold semiconductive Method for manufacturing a body element. 2. The method according to claim 1, wherein at least one concave or convex portion is formed on the inner diameter side of the insulating device. 3. The method according to claim 1, wherein the semiconductor substrate has at least one junction surface between semiconductor layers having different pn junction conductivity types or impurity concentrations.