JP2002134669A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of cracks that occur on a connection terminal connecting an insulation board and an outer circuit board in the case that a temperature cycle test is performed, or cracks and peeling that occur on an adhesion resin connecting a cover body and the insulation board. SOLUTION: In a semiconductor device A provided with the plate-like cover body 3 mounting a semiconductor element 2 on the surface of the insulation board 1, attached to the surface of the insulation board 1 so as to cover the semiconductor element 1 and adhering a part thereof through a heat conduction resin 9 on the upper face of the semiconductor element 2 and mounted on the outer circuit board 11 through the connection terminal 10, thermal expansion coefficients lessen in order of the outer circuit board 11, the insulation board 1 and the cover body 3, the cover body 3 and the insulation board 1 are adhered by the adhesion resin different in Young's modulus, the adhesion resin 4b of large Young's modulus is positioned in the inside of the cover body 3 more inward than the adhesion resin 4a of small Young's modulus. The cracks and peeling do not occur on the connection terminal and the adhesion resins 4a, 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a heat-dissipating lid for use in an information processing device such as a computer, and more particularly, to a semiconductor device having a temperature cycling function when a temperature cycle is repeatedly applied to the semiconductor device. The present invention relates to a semiconductor device in which a connection terminal for connecting a semiconductor device to an external circuit board is not broken and a heat conductive resin for connecting a lid and a semiconductor element is not broken or peeled.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device having a heat-dissipating lid used for an information processing apparatus such as a computer has a substantially flat insulating substrate 21 and a semiconductor element as shown in a sectional view of FIG. It is basically composed of 22 and a cap-shaped lid 23.

The insulating substrate 21 is made of a ceramic material such as an aluminum oxide sintered body or a glass ceramic sintered body, has a mounting portion for mounting the semiconductor element 22 at the center of the upper surface, and extends from the mounting portion to the lower surface. A plurality of metallized wiring layers 24 to be formed.

[0004] The semiconductor element 22 is mounted on a mounting portion at the center of the upper surface of the insulating substrate 21, and each connection electrode 25 formed on the lower surface of the semiconductor element 22 and the metallized wiring layer 24 of the insulating substrate 21 are connected to conductive bumps. By joining at 26, each connection electrode 25 of the semiconductor element 22 and the metallized wiring layer 24 are electrically connected.

[0005] Thereafter, a cap-shaped lid 23 is bonded to the upper surface of the semiconductor element 22 with a heat conductive resin 27 to form an insulating substrate 21.
By attaching it to the outer edge of the upper surface with adhesive resin 28,
The semiconductor device B is manufactured.

In the semiconductor device B, the metallized wiring layer 24 on the lower surface of the insulating substrate 21 is connected to a connecting conductor of an external circuit board 29 such as a mother board made of a resin substrate such as a glass epoxy resin.
It is mounted on the external circuit board 29 by connecting to 30 via a connection terminal 31 made of solder or the like.

[0007] Such a semiconductor device needs to be subjected to the following temperature cycle test, and it is recognized as a product only after it has been confirmed that the semiconductor device has durability equal to or higher than a predetermined value in the temperature cycle test. That is, this temperature cycle test is a reliability test for confirming the durability of a semiconductor device against extremely high or low temperatures and the durability when the semiconductor device is alternately exposed to high and low temperatures. For example, the following procedure [1] ]
To [6].

[1] Using a thermostat at -40 ° C and a thermostat at 125 ° C, first, the sample is transferred from a room temperature (25 ° C) to a thermostat at -40 ° C and held for 10 to 15 minutes.

[2] The sample is transferred to the air at room temperature (25 ° C.).

[3] Within 1 minute after taking out from the -40 ° C. constant temperature bath, the sample is transferred from the air at room temperature (25 ° C.) to a 125 ° C. constant temperature bath and held for 10 to 15 minutes.

[4] The sample is transferred to the air at room temperature (25 ° C.).

[5] The sample is taken out of the thermostat at 125 ° C. and is transferred from the air at room temperature (25 ° C.) to a thermostat at −40 ° C. within one minute.

[6] One cycle of the above [1] to [5], that is, room temperature (25 ° C.) → low temperature (−40 ° C.) → room temperature (25 ° C.)
This cycle is repeated a predetermined number of times (for example, 1000 cycles) with a temperature change of (° C.) → high temperature (125 ° C.) → room temperature (25 ° C.) as one cycle.

When a temperature cycle test is performed on the semiconductor device B, the temperature is increased from room temperature (25 ° C.) to a high temperature (125 ° C.).
The connection terminals 31 for connecting the insulating board 21 and the external circuit board 29 are connected to the insulating board 21 and the external circuit board in both the process of raising the temperature to room temperature and the process of lowering the temperature from room temperature (25 ° C.) to low temperature (-40 ° C.). Cracks may occur due to thermal stress generated between them, and the occurrence of cracks is remarkable in the course of cooling. It is for the following reasons.

That is, since the Young's modulus of the insulating substrate 21, the lid 23 and the external circuit board 29 is small at a high temperature and large at a low temperature, the lid 23, the insulating substrate 21 and the external circuit board 29 are separated from each other during the heating process. It can easily bend in the direction in which the side becomes concave, and the thermal stress generated between the insulating substrate 21 and the external circuit board 29 can be reduced. On the other hand, during the cooling process,
Since the Young's modulus of each of 21, the lid 23, and the external circuit board 29 is larger than the temperature increasing process, the lid 23, the insulating substrate 21, and the external circuit board 29 are hardly bent.

Therefore, the thermal stress generated between the insulating substrate 21 and the external circuit substrate 29 increases in the temperature lowering process as compared with the temperature increasing process. Therefore, the connection terminals 31 that connect the insulating substrate 21 and the external circuit board 29 are more likely to crack in the temperature decreasing process than in the temperature increasing process.

In the structure of the conventional semiconductor device B, the coefficient of thermal expansion is 4 in a temperature cycle test, especially in a temperature decreasing process.
８8 × 10 ^-6 / ℃ insulating substrate 21 and thermal expansion coefficient about 15-20 ×
There is a problem that thermal stress generated in the connection terminal 31 is increased due to a difference in thermal expansion coefficient between the external circuit board 29 and 10 ^-6 / ° C.

In the structure of the conventional semiconductor device B, a cap-like lid 23 is attached to the outer edge of the upper surface of the insulating substrate 21 as shown in FIG. Therefore, the insulating substrate 21 is
In the temperature cycle test, especially in the temperature drop process, the connection terminal 31 for connecting the semiconductor device B and the external circuit board 29 cannot bend sufficiently in the direction in which the upper side becomes convex in the temperature cycle test. There has been a problem that the generated thermal stress cannot be reduced.

In particular, when the coefficient of thermal expansion of the lid 23 and the external circuit board 29 is larger than the coefficient of thermal expansion of the insulating substrate 21, the insulating substrate 21 is subjected to a temperature cycle test, especially during the process of lowering the temperature from room temperature to a low temperature. Since it is constrained by both the bonding portion with the lid 23 and the connection terminal 31, it cannot bend sufficiently in the direction in which the upper side is convex, and the thermal stress generated in the connection terminal 31 in the main surface direction of the insulating substrate 21 is reduced. It cannot be made smaller.

When such thermal stress is repeatedly applied,
There has been a problem that the connection terminal 31 is broken by thermal fatigue and cracks are generated near the connection portion of the connection terminal 31.

To solve these problems, a semiconductor device having a structure shown in FIG. 7 has been proposed (IEEE).
Sponsored 50th Electronic Components & Technology Conf
erence abstracts, pages 1189-1197).

FIG. 7 is a sectional view of the semiconductor device C.
As shown in FIG. 7, the semiconductor device C is a substantially flat insulating substrate.
It is basically composed of 41, a semiconductor element 42, and a flat lid 43.

An insulating substrate 41 has a semiconductor element 42
And a plurality of metallized wiring layers 44 extending from the mounting portion to the lower surface.

Then, the semiconductor element 42 is mounted on the mounting portion at the center of the upper surface of the insulating substrate 41, and each connection electrode 45 formed on the lower surface of the semiconductor element 42 and the metallized wiring layer 44 of the insulating substrate 41 are connected to the conductor. By bonding with the bump 46, each connection electrode 45 of the semiconductor element 42 is electrically connected to the metallized wiring layer 44.

Thereafter, the semiconductor device C is manufactured by attaching the lid 43 to the upper surface of the semiconductor element 42 with a thermally conductive resin 47 and attaching the lid 43 to the upper surface of the insulating substrate 41 with an adhesive resin 48. You.

In this semiconductor device C, the metallized wiring layer 44 on the lower surface of the insulating substrate 41 is connected to a connecting conductor of an external circuit board 49 such as a mother board made of a resin substrate such as glass epoxy resin.
It is mounted on the external circuit board 49 by connecting it to a connection terminal 50 via a connection terminal 51 made of solder or the like.

Here, by changing the shape of the cover 43 from a cap shape to a plate shape, the rigidity of the cover 43 is reduced.
Since the restraint on the insulating substrate 41 is reduced, the insulating substrate 41 can bend in a direction in which the lid 43 side (upper side) is convex in the temperature cycle test, particularly in the temperature decreasing process.
As a result, it is possible to reduce the thermal stress generated in the connection terminal 51 that connects the semiconductor device C and the external circuit board 49.

Further, since the thermal expansion coefficient of the lid 43 is smaller than the thermal expansion coefficient of the insulating substrate 41, the lid 43, the insulating substrate 41, and the external circuit board 49 also have convex upper sides in the same temperature decreasing process. Thus, the thermal stress generated in the connection terminals 51 between the insulating substrate 41 and the external circuit board 49 can be reduced.

By lowering the Young's modulus of the adhesive resin 48 connecting the lid 43 and the insulating substrate 41 to 0.011 GPa, the insulating substrate 41 and the lid 43 are particularly reduced in the temperature decreasing process from room temperature to low temperature. When flexing, the adhesive resin 48 can follow the deformation.

According to the above-described improvement, the thermal stress generated due to the difference in thermal expansion coefficient between the insulating substrate 41 and the external circuit board 49 during the temperature cycle test, especially during the temperature drop process, is reduced by the lid 43 and the insulating substrate 41.
And the external circuit board 49 can be made smaller by flexing so that the upper side becomes convex.
The connection terminal 51 connecting the external circuit board 49 to the external circuit board 49 is no longer cracked.

[0031]

However, in this conventional semiconductor device C, cracks do not occur in the connection terminals 51 connecting the insulating substrate 41 and the external circuit board 49, but
Due to the difference in thermal expansion coefficient between the insulating substrate 41 and the lid 43, the insulating substrate 41
In addition, a large thermal stress is generated in the adhesive resin 48 on the outer peripheral portion of the lid 43, and the adhesive resin 48 may be broken. As a result, a heat conductive resin 47 that dissipates heat generated in the semiconductor element 42
Is peeled off from the lid 43 or cracks are generated in the heat conductive resin 47, so that there is a problem that the heat dissipation of the semiconductor element 42 may be reduced.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a semiconductor device having a connection terminal for connecting an insulating substrate to an external circuit board when the semiconductor device is subjected to a temperature cycle test. Crack due to thermal stress caused by the difference in thermal expansion coefficient between the semiconductor device and the external circuit board, and the heat conductive resin bonding the semiconductor element and the lid does not peel off from the lid, good heat dissipation To provide a simple semiconductor device.

[0033]

According to the present invention, there is provided a semiconductor device comprising:
On the surface of the insulating substrate on which the metallized wiring layer is
A semiconductor element provided with a connection electrode is placed, and the metallized wiring layer and the connection electrode of the semiconductor element are joined together, and attached to the insulating substrate surface so as to cover the semiconductor element; A flat lid formed by bonding a part thereof to the upper surface of the semiconductor element via a heat conductive resin, and a connection terminal provided on the back surface of the insulating substrate and electrically connected to the semiconductor element. A semiconductor device mounted on the external circuit board by joining the metallized wiring layer on the lower surface of the insulating substrate and the connection conductor on the upper surface of the external circuit board via the connection terminal; The substrate, the insulating substrate, and the lid become smaller in this order, and the lid and the insulating substrate are attached with adhesive resins having different Young's moduli, and the adhesive resin having a large Young's modulus has a small Young's modulus. And it is characterized in that it is located inside of the lid than the adhesive resin are.

According to the present invention, the thermal expansion coefficient is reduced in the order of the external circuit board, the insulating substrate, and the lid by the above configuration. In addition, the insulating substrate and the external circuit board are bent such that the lid side is convex, so that thermal stress due to a difference in thermal expansion coefficient between the insulating substrate, the external circuit board, and the lid can be reduced.

Further, since the upper surface of the semiconductor element is adhered to the lid with a heat conductive resin, the heat generated in the semiconductor element is effectively transmitted to the lid side. Dispersibility can be improved.

Further, since the lid and the insulating substrate are attached with adhesive resins having different Young's moduli, and the adhesive resin having a higher Young's modulus is located inside the lid than the adhesive resin having a lower Young's modulus. In the same manner, in the temperature decreasing process, the restraint of the insulating substrate by the lid can be reduced by the deformation of the adhesive resin having a small Young's modulus at the connection portion. As a result, the insulating substrate bends so that the lid side becomes convex, and the insulating substrate is bent. Thermal stress due to the difference in thermal expansion coefficient of the external circuit board can be reduced. Further, the adhesive resin having a large Young's modulus reinforces the bonding between the lid and the insulating substrate, so that the mechanical strength of the bonding can be increased. Therefore, the thermal conductive resin does not peel off from the lid, so that it is possible to maintain and secure the thermal connection between the semiconductor element and the lid,
A semiconductor device having good heat dissipation properties and excellent long-term reliability of bonding between the lid and the insulating substrate can be obtained.

Here, since the thermal stress between the lid and the insulating substrate increases in proportion to the distance from the center of the lid, the distance from the center of the lid is long and the thermal stress on the lid outer peripheral side is large. An adhesive resin having a small Young's modulus, which is easy to perform, and an adhesive resin having a large strength and a large Young's modulus are arranged inside the lid, which is short from the center of the lid. As a result, by placing the adhesive resin with a small Young's modulus on the outer periphery of the lid,
Since the adhesive resin having a small Young's modulus is easily deformed, the resin is deformed in accordance with the thermal stress in the planar direction which becomes larger on the outer peripheral side of the insulating substrate in the temperature decreasing process of the temperature cycle test. In addition, since the adhesive resin having a large Young's modulus is disposed inside the lid, the adhesive resin having a large Young's modulus has high mechanical strength and is not easily deformed, so that the connection between the insulating substrate and the lid is strengthened.

Further, in the semiconductor device according to the present invention, in the above structure, preferably, the lid is made of a sintered body of a composite material containing aluminum and silicon carbide as main components. As a result, the density of the lid material is lower than the density of other commonly used materials including copper and tungsten as a main component, and the weight of the semiconductor device is reduced as compared with the lid having the same shape. It is possible to prevent the mounting height from being reduced due to the deformation of the connection terminal with the substrate due to the weight of the semiconductor device. As a result, in a temperature cycle test, especially when a thermal stress occurs due to a difference in thermal expansion coefficient between the insulating substrate and the external circuit board during the temperature lowering process from room temperature to a low temperature, the mounting height of the semiconductor device with respect to the external circuit board Is not reduced, the connection terminal between the insulating substrate and the external circuit board can be easily deformed in the mounting surface direction, and the generated thermal stress can be reduced. Therefore, the connection between the semiconductor device and the external circuit board is less likely to be broken, and the connection reliability between the insulating substrate and the external circuit board can be further improved.

[0039]

Next, the present invention will be described with reference to the accompanying drawings.

FIGS. 1A and 1B are a plan view and a sectional view, respectively, showing an example of an embodiment of a semiconductor device according to the present invention. In FIG. 1, reference numeral 1 denotes an insulating substrate, 2 denotes a semiconductor element, and 3 denotes a flat lid.
Are adhesive resins having different Young's moduli, that is, adhesive resin 4a having a small Young's modulus and adhesive resin 4 having a large Young's modulus.
b.

The insulating substrate 1 is made of, for example, a ceramic insulating material such as a glass ceramic sintered body or an electrical insulating material such as a resin insulating material such as a glass epoxy resin or a glass polyimide resin composite material.

When the insulating substrate 1 is made of, for example, a glass ceramic sintered body, an organic binder and a solvent are appropriately added to a mixed powder obtained by appropriately mixing glass and a predetermined filler to obtain a slurry. After being formed into a sheet, the sheet-shaped molded body is laminated and pressed to produce a laminate, and the laminate is subjected to air or nitrogen in an atmosphere.
It is manufactured by firing at 0 ° C. to 1000 ° C.

The insulating substrate 1 is provided with a metallized wiring layer 5 extending from the front surface to the inner surface to the rear surface. If the insulating substrate 1 is made of, for example, a glass ceramic sintered body, the metallized wiring layer 5 is formed with a through hole in advance at a predetermined position of the sheet-like molded body by punching or laser if necessary, It is formed by printing a conductive paste obtained by appropriately adding an organic binder and a solvent to a metal powder containing copper or silver as a main component and kneading the metal paste in a through-hole and on the surface of a sheet-like molded body by a screen printing method or the like. You. In addition, the metallized wiring layer 5 may be made of, for example, a metal material mainly containing gold, aluminum, nickel, lead-tin alloy or the like.

The semiconductor element 2 is made of a semiconductor such as silicon or gallium-arsenic, and has a plurality of connection electrodes 6 on its lower surface. The connection electrode 6 is joined and electrically connected to the metallized wiring layer 5 on the surface of the insulating substrate 1 via a conductor bump 7 made of a metal such as solder or gold.

The connection between the connection electrode 6 and the metallized wiring layer 5 by the conductor bump 7 is performed, for example, by bonding the conductor bump 7 to the connection electrode 6 of the semiconductor element 2 by welding, crimping, or plating. A method of contacting and joining the metallized wiring layer 5 of the insulating substrate 1 can be adopted.

The space between the semiconductor element 2 and the insulating substrate 1 around the conductor bump 7 is usually filled with a thermosetting resin 8 to reinforce the bonding between the semiconductor element 2 and the insulating substrate 1.

Semiconductor element 2 mounted on the surface of insulating substrate 1
, That is, the surface opposite to the surface on which the semiconductor element 2 is mounted on the insulating substrate 1, via the heat conductive resin 9.
A flat lid 3 having a smaller thermal expansion coefficient is bonded. Then, the lid 3 and the insulating substrate 1 are bonded to each other with an adhesive resin having a different Young's modulus, that is, an adhesive resin 4a having a small Young's modulus and an adhesive resin 4b having a large Young's modulus disposed inside thereof.
The semiconductor device A is configured by being attached via the.

Then, the semiconductor device A includes the insulating substrate 1
An external circuit board 11 having a larger coefficient of thermal expansion than the insulating board 1 is provided on the lower surface of the metallized wiring layer 5 via connection terminals 10 such as solder.
By connecting to the connection conductor on the upper surface, the external circuit board 11
The connection electrode 6 of the semiconductor element 2 mounted and mounted thereon is electrically connected to the connection conductor of the external circuit board 11.

According to the semiconductor device A of the present invention, when mounted on the external circuit board 11, the coefficient of thermal expansion is reduced in the order of the external circuit board 11, the insulating substrate 1, and the cover 3. From the above, in the temperature cycle test, especially in the temperature decreasing process, the insulating substrate 1 and the lid 3 are both convex on the lid 3 side due to the difference in thermal expansion coefficient between the external circuit board 11, the insulating substrate 1 and the lid 3. It can be bent. For this reason, the thermal stress in the plane direction generated in the connection terminal 10 for connecting the insulating substrate 1 and the external circuit board 11 can be reduced by bending, and the connection terminal 10 is less likely to be broken by the thermal stress.

The adhesive resin for connecting the lid 3 and the insulating substrate 1 is composed of an adhesive resin 4a having a small Young's modulus and an adhesive resin 4b having a large Young's modulus disposed inside the lid 3 than that.
It is composed of The adhesive resin 4a having a small Young's modulus is easily deformed, and the cover 3 and the insulating substrate 1
Deforms following the thermal deformation of the material and is not destroyed.
For example, in the cooling process of the temperature cycle test,
And the insulating substrate 1 is deformed in a direction in which the upper side is convex,
Since the amount of deflection between the lid 3 and the insulating substrate 1 is different, the difference in the amount of deflection becomes larger toward the outside of the lid 3. On the other hand, the adhesive resin 4a existing outside the adhesive resin 4b can follow the difference in the amount of deflection by being greatly deformed, so that both the lid 3 and the insulating substrate 1 are convex on the upper side. And the thermal stress generated in the connection terminal 10 can be reduced, so that the connection terminal 10 is hardly broken.

On the other hand, the adhesive resin 4b having a large Young's modulus firmly connects the lid 3 and the insulating substrate 1. In addition, during the cooling process of the temperature cycle test, the lid 3 and the insulating substrate 1
Is deformed in a direction in which the upper side is convex, but thermal stress is generated on the upper surface of the insulating substrate 1 outward in the surface direction, and the thermal stress increases toward the outside. Therefore, the thermal stress applied to the adhesive resin 4b existing inside the adhesive resin 4a is small, and the deformation of the adhesive resin 4b due to the thermal stress can be small. As a result, the adhesive resin 4b that is not easily deformed is hardly broken by thermal stress.

The semiconductor device A of the present invention is sometimes mounted vertically on the external circuit board 11 in order to improve the mounting density. 1 is reinforced by the adhesive resin 4b, the mechanical strength of the connection between the lid 3 and the insulating substrate 1 is high, and there is no problem.

Further, since the adhesive resin 4b having a large Young's modulus is located on the inner side of the lid 3 with respect to the adhesive resin 4a having a small Young's modulus, the adhesive resin 4b does not hinder the deformation of the adhesive resin 4a. Even if a large thermal stress is generated on the outer peripheral side of the upper surface of the substrate 1, the adhesive resin 4a is largely deformed and can follow the deformation of the insulating substrate 1 due to the thermal stress.

Here, the adhesive resin 4a and the adhesive resin 4b
Are preferably arranged at the four corners of the rectangular lid 3 because a larger area for mounting electronic components such as the semiconductor element 2 and chip capacitors and chip resistors on the upper surface of the insulating substrate 1 can be ensured.

Since the volume of the adhesive resin 4a is not destroyed even if the adhesive resin 4a is largely deformed following the deformation due to the thermal stress generated between the lid 3 and the insulating substrate 1,
Is preferably less than 50 mm ³ exceed 0.3 mm ^3. The volume of the adhesive resin 4b is more than 0.3 mm ³ and more than 20 mm in order to make the connection between the lid 3 and the insulating substrate 1 stronger.
It is preferably less than mm ³ .

Further, the volume of the adhesive resin 4b and the adhesive resin 4b
The relationship between the adhesive resin 4a and the insulating substrate 1 is such that the adhesive resin 4a is easily deformed following the deformation due to the thermal stress generated between the lid 3 and the insulating substrate 1. It is preferable that the value obtained by dividing the volume of the adhesive resin 4b by the volume of the adhesive resin 4a is more than 0.5 and less than 2 in order to simultaneously exhibit both the effect of strengthening the connection with the adhesive resin 4b.

The bonding area of the adhesive resin 4a and the adhesive resin 4b with the insulating substrate 1 or the lid 3 is
a is 0.7 mm ² to effectively follow the deformation of the lid 3 and the insulating substrate 1 due to thermal stress.
And less than 80 mm ² , and the adhesive resin 4 b is more than 0.7 mm ² and 35 mm, respectively, in order to strengthen the mechanical connection between the lid 3 and the insulating substrate 1.
Preferably it is less than ² .

Further, regarding the bonding area of the adhesive resin 4a between the insulating substrate 1 and the lid 3, it is preferable that the bonding area with the insulating substrate 1 is larger than the bonding area with the lid 3. In this case, during the cooling process of the temperature cycle test, the lid 3
A larger thermal stress is generated on the upper surface of the insulating substrate 1 than the lower surface of the lid 3, and the shear stress due to the large thermal stress is absorbed and reduced by the large bonding area. Thus, it is possible to prevent the adhesive surface with the insulating substrate 1 from peeling off. More preferably, 1 ≧ (adhesive area with lid 3) / (adhesive area with insulating substrate 1)> 1
/ 4 is good. If (the bonding area with the lid 3) / (the bonding area with the insulating substrate 1) is 1/4 or less, a large constricted portion is formed at the intermediate portion in the height direction of the adhesive resin 4a, and the temperature cycle is repeated many times. In such a case, the adhesive resin 4a tends to be easily broken at the constricted portion by repeatedly deforming the constricted portion.

As for the adhesive resin 4b, the same effect can be obtained by making the adhesive area with the insulating substrate 1 larger than the adhesive area with the lid 3 as described above. Since the stress is smaller than that of the adhesive resin 4a, the above configuration is not necessarily required. Therefore, the adhesive resin 4b may be, for example, a substantially columnar resin having an adhesive area with the insulating substrate 1 and an adhesive area with the lid 3 substantially the same.

The heights of the adhesive resin 4a and the adhesive resin 4b are the height of the lid 1 from the insulating substrate 1, and the height is the thickness of the semiconductor element 2, the height of the conductive bumps 7, and the heat. It is determined by the sum of the thicknesses of the conductive resin 9, and usually 0.2 mm is the lower limit. On the other hand, if the height of the adhesive resin 4a and the height of the adhesive resin 4b are too high, the gap between the semiconductor element 2 and the lid 3 is widened, and the thickness of the heat conductive resin 9 for bonding them is increased. The semiconductor device 2 may be thermally runaway or malfunction,
Preferably, it is less than 3 mm.

When the thermal conductivity of the heat conductive resin 9 for bonding the lid 3 and the semiconductor element 2 is low, the heat generated by the semiconductor element 2 is difficult to be effectively radiated, and the heat generated by the semiconductor element 2 is hardly radiated. The temperature may rise and thermal runaway may occur. Therefore,
The thermal conductivity of the thermally conductive resin 9 is preferably high, specifically, 1 W / (m · K) or more.

It is preferable to connect the radiating fins 12 to the upper surface of the lid 3, which increases the surface area of the radiating surface, thereby further improving heat dissipation.

In the semiconductor device A of the present invention, when the coefficient of thermal expansion of the insulating substrate 1 at 40 to 400 ° C. is less than 8 × 10 ⁻⁶ / ° C., the coefficient of thermal expansion of the external circuit board 11 is 15 to 20 × 10 ^{−. 6} /
The difference in thermal expansion coefficient from C.C. increases, and in the temperature cycle test, especially in the process of lowering the temperature from room temperature to a low temperature, the thermal stress of the connection terminal 10 between the insulating substrate 1 and the external circuit board 11 becomes extremely large, and the connection terminal 10 breaks It tends to be easier.

On the other hand, when the thermal expansion coefficient of the insulating substrate 1 at 40 to 400 ° C. exceeds 14 × 10 ⁻⁶ / ° C., the thermal expansion coefficient of the insulating substrate 1 becomes smaller than the thermal expansion coefficients of the lid 3 and the external circuit board 11. In some cases, the insulating substrate 1 cannot bend in the direction in which the insulating substrate 1 is convex toward the lid 3, and as a result, the thermal stress generated between the insulating substrate 1 and the external circuit board 11 can be reduced. In the same manner, particularly in the process of lowering the temperature from room temperature to a low temperature, the thermal stress applied to the connection terminal 10 connecting the insulating substrate 1 and the external circuit board 11 increases, and the connection terminal 10 may be broken.

Therefore, the thermal expansion coefficient of the insulating substrate 1 is 8 × 10
Range of ^{-6 / ℃ ~14 × 10 -6 /} ℃ is preferred.

For the lid 3 in the semiconductor device A of the present invention, various materials can be used as long as the lid has a smaller thermal expansion coefficient than the insulating substrate 1. While having the necessary strength, its thermal conductivity
It is preferable to use a material having excellent thermal conductivity exceeding 100 W / m · K. As such a material, for example, a sintered body of a composite material containing aluminum and silicon carbide as main components,
A composite material mainly containing copper and tungsten, a composite material mainly containing copper and molybdenum, a material mainly containing copper-free oxide, a sintered aluminum nitride, and the like can be given.

In particular, the semiconductor device A of the present invention has a cover 3
Is made of a sintered body of a composite material containing aluminum and silicon carbide as main components, the density of the lid 3 is about 3 g / cm ³ while having sufficient strength. Since the density of the composite material containing copper and tungsten as the main components used for is lower than 14 to 17 g / cm ³ ,
Since the weight of the semiconductor device A is reduced and the connection terminals 10 connecting the semiconductor device A and the external circuit board 11 are not greatly deformed, a reduction in the mounting height of the semiconductor device A on the external circuit board 11 is reduced. Can be. As a result, the insulating substrate 1
And the external circuit board 11 can further improve the connection reliability.

Next, another example of the embodiment of the semiconductor device of the present invention is shown in FIGS. 2, 3, 4 and 5. FIG. These figures are the same plan views as FIG. 1A in which the semiconductor device is viewed from the lid 3 side. However, in these figures, the same parts as those in the example shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Parts not shown have the same configuration as the example shown in FIG. Further, the adhesive resins 4a and 4b are shown in a see-through state to show the arrangement thereof, and FIG. 5 also shows the insulating substrate 1 in a see-through state.

In the example shown in FIG. 2, the adhesive resin 4a is provided at four places at the center of four sides of the outer peripheral region of the rectangular lid 3.
And the adhesive resin 4b is arranged at the center of the four sides of the outer peripheral region at four locations which are substantially equidistant from the center of the lid 3 than the adhesive resin 4a.
As described above, if the bonding position of the adhesive resin 4a and the bonding resin 4b is located between the center and the center of the four sides of the lid 3, the distance between the bonding position and the center of the lid 3 is short. The amount of deformation due to the difference in the coefficient of thermal expansion between the body 3 and the insulating substrate 1 is reduced, the followability due to the deformation of the adhesive resin 4 a having a small Young's modulus is improved, and the adhesive resin 4 having a large Young's modulus is improved.
The effect of reinforcing the joint between the lid 3 and the insulating substrate 1 by b is more effective.

In the example shown in FIG. 3, the adhesive resin 4a is arranged in a rectangular shape at substantially four corners of the four corners of the rectangular lid 3 at substantially the same distance from the center of the lid 3, and 4b
The distance from the center of the lid 3 to the center of the lid 3 is shorter than the adhesive resin 4a on substantially the diagonal of the four corners of the lid 3, and the four corners are arranged at substantially the same distance from the center of the lid 3. Thus, the adhesive resin 4
If a is formed in a U-shape, the adhesive resin 4a is deformed in the vertical direction and the horizontal direction (corresponding to the direction of each side of the U-shape) in FIG. By doing so, it is possible to follow the deformation due to thermal stress in each of the vertical direction and the horizontal direction of the lid 3 in the plane direction.

In the example shown in FIG. 4, the adhesive resin 4a is applied to the center of the four sides of the outer peripheral area of the rectangular lid 3 at substantially the same distance from the center of the lid 3 so that the adhesive surface of the adhesive resin 4a is Are arranged in a rectangular shape in which the directions of the four sides of the lid 3 are long sides, and the adhesive resin 4b is disposed at four central portions of the center of the four sides where the distance from the center of the lid 3 is shorter than the adhesive resin 4a and almost equal to each other. Have been placed. As described above, if the bonding surface of the adhesive resin 4a is formed in a rectangular shape in which the four sides of the lid 3 are long sides, the adhesive resin 4a is deformed in the directions of the four sides of the lid 3 so that the lid 3 is deformed. It can absorb the thermal stress in each direction of the four sides of the body 3 and can follow the deformation due to the thermal stress.

In the example shown in FIG. 5, the circular lid 3 and the quadrangular insulating substrate 1 are placed at four locations substantially equidistant from the center of the lid 3 on substantially diagonal lines of the four corners of the insulating substrate 1. The adhesive resin 4a is used for bonding, and the adhesive resin 4a is used for bonding at four locations on the diagonal of the four corners of the insulating substrate 1 which are shorter than the adhesive resin 4a from the center of the lid 3 and are almost equidistant. In this manner, by forming the lid 3 into a circle whose radius is substantially equal to one half of the length of the diagonal line of the insulating substrate 1, the heat radiation area of the lid 3 can be made larger, and In order to increase the area, the size can be reduced as compared with a case where a rectangular lid having a larger area than the insulating substrate 1 is provided.

The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the scope of the present invention. For example, an adhesive resin having a small Young's modulus, an adhesive resin having an intermediate Young's modulus, and an adhesive resin having a large Young's modulus are arranged at four positions on a diagonal line of the four corners of the lid in order of increasing distance from the center of the lid. The configuration may be as follows.

[0074]

Next, embodiments of the present invention will be described below.

Using ceramic materials A and B shown in Table 1 as ceramic materials for an insulating substrate, an insulating substrate was experimentally manufactured as follows. An organic binder and a solvent are appropriately added to the mixed powder of each raw material powder to obtain a slurry, the slurry is molded into a sheet having a thickness of 0.25 mm, and then 20 sheet-like molded bodies are laminated and pressed to form a laminated body. Then, the laminate was fired at a maximum temperature of 900 to 1000 ° C. in a nitrogen atmosphere to produce a sintered body having a size of 5 mm × 4 mm × 40 mm. Table 1 shows the results of measuring the Young's modulus and the coefficient of thermal expansion of each of the obtained sintered bodies.

[0076]

[Table 1]

Next, a semiconductor device having the structure shown in FIG. 1 was manufactured by the following steps [1] to [10].

[1] An organic binder and a solvent were appropriately added to the raw material powders of the ceramic materials A and B shown in Table 1 to obtain a slurry, and the slurry was formed into a sheet having a thickness of 0.1 mm.

[2] A perforation was punched out at a position where a through-hole was formed in the sheet-like molded product using a mold.

[3] In order to form a wiring conductor layer on the surface and the inner layer of the sheet-like molded body, a conductor paste containing copper as a main component was printed and applied by a screen printing method. In addition, a conductive paste was printed and applied to the sheet-shaped molded body corresponding to the uppermost surface at a portion where the semiconductor element was connected, and further a conductive paste was printed and applied to a portion connected to the external circuit board to the sheet-shaped molded body corresponding to the bottom surface. .

[4] Twenty sheet-shaped moldings are laminated and pressed to form a laminate, and the laminate is placed in a nitrogen atmosphere at 900 to 1
It was fired at a maximum temperature of 000 ° C. to produce an insulating substrate. This insulating substrate has a length x width x thickness of 40 mm x 40 mm x 1 mm
It was the size of.

[5] On the metallized wiring layer on the bottom surface of the insulating substrate, a spherical connection terminal made of a high-melting solder made of a tin-lead alloy (tin: lead = 10: 90 by weight) and a low-melting solder (weight) (The ratio of tin: lead = 63: 37).

[6] After nickel plating is applied to the surface of the metallized wiring layer on the upper surface of the insulating substrate, a semiconductor element made of Si having a thermal expansion coefficient of 2.8 × 10 ⁻⁶ / ° C. at 0 to 100 ° C. is prepared. The connection electrode on the bottom surface of the element was mounted on the metallized wiring layer on the upper surface of the insulating substrate by connecting it with low melting point solder.

[7] A thermosetting resin (epoxy resin) is injected into the gap between the semiconductor element and the insulating substrate.
The semiconductor element was fixed on the upper surface of the insulating substrate by heat treatment and curing for a time.

[8] A silicone resin as a heat conductive resin was applied to the upper surface of the semiconductor element mounted on the upper surface of the insulating substrate.

[9] In a sintered body of a composite material containing aluminum and silicon carbide as main components, the coefficient of thermal expansion changes according to the mixing ratio, and the mixing ratio is such that the weight ratio of silicon carbide is 70% by weight.
And when aluminum is 30% by weight, the coefficient of thermal expansion is 8 × 10
⁻⁶ / ° C., and when the mixing ratio is 50% by weight of silicon carbide and 50% by weight of aluminum, the coefficient of thermal expansion is 12 × 10 ⁻⁶ / ° C. At the bonding portion between the lid and the insulating substrate with a predetermined mixing ratio,
After applying an adhesive resin having a large Young's modulus (epoxy resin) and an adhesive resin having a small Young's modulus (epoxy resin) to the insulating substrate by its own weight on the lower surface of the lid,
The lid was positioned and placed on the insulating substrate, and the adhesive resin was cured at 150 ° C. and joined to produce a semiconductor device.

[10] These semiconductor devices are made of a glass epoxy substrate and have a thermal expansion coefficient of 1 at -40 to 125 ° C.
A spherical connection terminal on the lower surface of the insulating board and a wiring conductor on the upper surface of the external circuit board are connected to an external circuit board on which a wiring conductor made of copper foil is formed on the surface of the insulating substrate at 5 × 10 ^-6 / ° C. The semiconductor device was mounted on the upper surface of the external circuit board by connecting with heat treatment at 240 ° C. for 3 minutes in a nitrogen atmosphere using low melting point solder.

The semiconductor device thus manufactured is
The following temperature cycle test was performed to examine the connection reliability between the insulating substrate and the external circuit board and the connection of the adhesive resin.

Here, for the above semiconductor device, the electric resistance between the wiring conductor of the external circuit board and the insulating substrate was measured before the temperature cycle test, and then the following [1] to
A temperature cycle test was performed according to the procedure of [6].

[1] Using a thermostat at -40 ° C and a thermostat at 125 ° C, the sample was first transferred from a room temperature (25 ° C) to a thermostat at -40 ° C and held for 10 to 15 minutes.

[2] The sample was transferred to the air at room temperature (25 ° C.).

[3] Within 1 minute after being taken out of the -40 ° C. constant temperature bath, the sample was transferred from the air at room temperature (25 ° C.) to a 125 ° C. constant temperature bath and held for 10 to 15 minutes.

[4] The sample was transferred to the air at room temperature (25 ° C.).

[5] Within 1 minute after being taken out of the thermostat at 125 ° C., the sample was transferred from the air at room temperature (25 ° C.) to a thermostat at −40 ° C.

[6] One cycle of the above [1] to [5], that is, room temperature (25 ° C.) → low temperature (−40 ° C.) → room temperature (25 ° C.)
This cycle was repeated up to 1000 cycles with a temperature change of (° C.) → high temperature (125 ° C.) → room temperature (25 ° C.) as one cycle.

During the temperature cycle test, the electric resistance between the wiring conductor of the external circuit board and the insulating substrate was measured every 50 cycles, and the electric resistance was twice or more the electric resistance measured before the temperature cycle test. Continued until it became. Table 2 shows the number of cycles. The connection state of the adhesive resin disposed outside the lid was examined. Table 2 also shows the results.

[0097]

[Table 2]

As can be seen from Table 2, the thermal expansion coefficient decreases in the order of the external circuit board, the insulating substrate, and the lid, the Young's modulus of the outer adhesive resin is smaller than 1 GPa, and the Young's modulus of the inner adhesive resin is lower. The semiconductor device of the present invention, which is a case where the sample number is as large as 1 GPa or more, that is, sample numbers 5 to 7, 9, 10, 12
In ~ 14, 20 ~ 22, 24, 25, 27 ~ 29, in the temperature cycle test up to 1000 times, no crack etc. occurred in the connection terminal between the semiconductor device and the external circuit board, and a change in electric resistance was observed. And very stable and good electrical connection was maintained.
Further, the adhesion state of the adhesive resin for joining the lid and the insulating substrate was favorably maintained. On the other hand, the thermal expansion coefficient decreases in the order of the external circuit board, the insulating substrate, and the lid, but when the Young's modulus of the outer adhesive resin and the inner adhesive resin are both smaller than 1 GPa, No is 4,
In 8, 11, 19, 23, and 26, in the temperature cycle test up to 1000 times, cracks did not occur in the connection terminals, and no change in electric resistance was observed between the external circuit board and the insulating board. The strength of the entire adhesive resin for joining the body and the insulating substrate is insufficient, and the outer adhesive resin tends to be cracked and easily peeled off.

The coefficient of thermal expansion decreases in the order of the external circuit board, the insulating substrate, and the lid, but when the Young's modulus of the outer adhesive resin is higher than 1 GPa and the Young's modulus of the inner adhesive resin is higher than 1 GPa. That is, sample Nos. 1, 3,
In 16 and 18, the adhesion of the adhesive resin joining the lid and the insulating substrate was maintained well, but cracks etc. occurred in the connection terminals in less than 1000 cycles of the temperature cycle test, and the connection between the insulating substrate and the external circuit board Electric resistance tended to increase.

The coefficient of thermal expansion decreases in the order of the external circuit board, the insulating substrate, and the lid, but when the Young's modulus of the outer adhesive resin is as large as 1 GPa or more and the Young's modulus of the inner adhesive resin is as small as less than 1 GPa. That is, in Sample Nos. 2 and 17, the adhesion state of the adhesive resin for joining the lid and the insulating substrate was maintained well, but cracks and the like occurred in the connection terminals in less than 1000 cycles of the temperature cycle test, and There was a tendency for the electrical resistance between the external circuit board and the external circuit board to increase.

The outer adhesive resin has a Young's modulus of 1 GP.
a, less than a, the Young's modulus of the inner adhesive resin is 1 GPa
Although the above is large, when the coefficient of thermal expansion decreases in the order of the external circuit board, the lid, and the insulating substrate, that is, in the case of the sample No. 15,
The adhesion of the adhesive resin joining the lid and the insulating substrate was maintained well, but cracks etc. occurred in the connection terminals after less than 1000 temperature cycle tests, and the electrical resistance between the insulating substrate and the external circuit board increased There was a tendency.

[0102]

According to the semiconductor device of the present invention, a semiconductor element having connection electrodes is placed on the surface of an insulating substrate on which a metallized wiring layer is formed, and the metallized wiring layer is connected to the semiconductor element. And a flat cover body attached to the surface of the insulating substrate so as to cover the semiconductor element and a part of which is bonded to the upper surface of the semiconductor element via a heat conductive resin. And a connection terminal provided on the back surface of the insulating substrate and electrically connected to the semiconductor element. The metallized wiring layer on the lower surface of the insulating substrate and the connection conductor on the upper surface of the external circuit board are joined via the connection terminal. As a result, in the semiconductor device mounted on the external circuit board, the coefficient of thermal expansion decreases in the order of the external circuit board, the insulating substrate, and the lid, and the lid and the insulating substrate are attached to each other with an adhesive resin having a different Young's modulus. Been And the adhesive resin having a large Young's modulus is located on the inner side of the lid than the adhesive resin having a small Young's modulus, and the thermal expansion coefficient of the external circuit board, the insulating substrate, and the lid is reduced. In the temperature cycle test, especially in the temperature decreasing process, the lid, the insulating substrate, and the external circuit board bend so that the lid side becomes convex, and the insulating substrate, the external circuit board, and the lid are bent. Thermal stress due to a difference in thermal expansion coefficient between the body and the body can be reduced.

Further, since the upper surface of the semiconductor element is adhered to the lid with a heat conductive resin, the heat generated in the semiconductor element is effectively transmitted to the lid side. Dispersibility can be improved.

In addition, since the lid and the insulating substrate are attached with adhesive resins having different Young's moduli, and the adhesive resin having a higher Young's modulus is located inside the lid than the adhesive resin having a lower Young's modulus. In the same manner, in the temperature decreasing process, the restraint of the insulating substrate by the lid can be reduced by the deformation of the adhesive resin having a small Young's modulus at the connection part. As a result, the insulating substrate bends so that the lid side becomes convex, and the insulating substrate is bent. Thermal stress due to the difference in thermal expansion coefficient of the external circuit board can be reduced. Further, the adhesive resin having a large Young's modulus reinforces the bonding between the lid and the insulating substrate, so that the mechanical strength of the bonding can be increased. Therefore, the thermal conductive resin does not peel off from the lid, so that it is possible to maintain and secure the thermal connection between the semiconductor element and the lid,
A semiconductor device having good heat dissipation properties and excellent long-term reliability of bonding between the lid and the insulating substrate can be obtained.

Further, according to the semiconductor device of the present invention, when the lid is made of a sintered body of a composite material containing aluminum and silicon carbide as main components, the lid keeps the strength while securing the strength. Since the density is reduced and the weight of the semiconductor device can be reduced, the mounting height can be prevented from being reduced due to the deformation of the connection terminal with the external circuit board due to the weight of the semiconductor device, and insulation can be performed in a temperature cycle test. Since the connection terminals between the board and the external circuit board can be easily deformed in the direction of the mounting surface, the generated thermal stress can be reduced. As a result, the connection between the semiconductor device and the external circuit board is less likely to be broken, and the connection reliability between the insulating substrate and the external circuit board can be further improved.

As described above, according to the present invention, when the temperature cycle test is performed, the thermal stress generated due to the difference in the thermal expansion coefficient between the insulating substrate and the external circuit board is applied to the connection terminal connecting the insulating substrate and the external circuit board. Thus, a semiconductor device having good heat dissipation, which does not cause cracks due to the above and does not peel off the heat conductive resin bonding the semiconductor element and the lid from the lid, can be provided.

[Brief description of the drawings]

FIGS. 1A and 1B are a plan view and a cross-sectional view, respectively, illustrating an example of an embodiment of a semiconductor device of the present invention.

FIG. 2 is a plan view showing another example of the embodiment of the semiconductor device of the present invention.

FIG. 3 is a plan view showing another example of the embodiment of the semiconductor device of the present invention.

FIG. 4 is a plan view showing another example of the embodiment of the semiconductor device of the present invention.

FIG. 5 is a plan view showing another example of the embodiment of the semiconductor device of the present invention.

FIG. 6 is a cross-sectional view illustrating an example of a conventional semiconductor device.

FIG. 7 is a sectional view showing another example of a conventional semiconductor device.

[Explanation of symbols]

 1: Insulating substrate 2: Semiconductor element 3: Lid 4a: Adhesive resin with small Young's modulus 4b: Adhesive resin with large Young's modulus 5: Metallized wiring layer 6: Connection electrode 9: Thermal conductive resin 10: Connection terminal 11: External circuit board 12: Heat radiation fin A: Semiconductor device

Claims (2)

[Claims] 1. A semiconductor device having a connection electrode is mounted on a surface of an insulating substrate on which a metallized wiring layer is formed, and the metallized wiring layer and a connection electrode of the semiconductor device are joined. A flat lid attached to the surface of the insulating substrate so as to cover the semiconductor element and a part of which is adhered to the upper surface of the semiconductor element via a thermally conductive resin; A connection terminal provided on the back surface of the substrate and electrically connected to the semiconductor element;
In a semiconductor device mounted on an external circuit board by joining a metallized wiring layer on the lower surface of the insulating substrate and a connection conductor on the upper surface of the external circuit board via the connection terminal, the coefficient of thermal expansion of the external circuit board is reduced. The substrate and the lid become smaller in this order, and the lid and the insulating substrate are attached by an adhesive resin having a different Young's modulus, and the adhesive resin having a large Young's modulus is more than the adhesive resin having a small Young's modulus. A semiconductor device, which is located inside a lid. 2. The semiconductor device according to claim 1, wherein said lid is made of a sintered body of a composite material containing aluminum and silicon carbide as main components.