JPH0794671A - Bonding structure of cap for hybrid integrated circuit device - Google Patents

Abstract

PURPOSE:To allow simultaneous operation of the sealing of a semiconductor element and the electrical connection of the circuit wiring layers on a board and a cap through low temperature steps by providing low temperature sealing material and conductive adhesive at the joint of the cap and the board. CONSTITUTION:Low temperature sealing agent 31 and conductive adhesive 37 are employed for electrically connecting the circuit wiring layers 15, 33 formed on the surface of a board 10 and on the rear of a cap 30 at the flange part 30a thereof and for bonding the lower surface of the cap 30 at the body part 30b thereof to the cap seal surface 13b. Consequently, the electrical connection of the board 10 and the cap 30 can be effected simultaneously with the hermetic sealing. This constitution reduces manpower in the production process thus enhancing the production efficiency. Furthermore, since the cap 30 is bonded through the conductive adhesive 37, as well as the sealing material 30, to increase the bonding area thus enhancing the bonding strength, a semiconductor element 16 can be sealed more reliably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap bonding structure for a hybrid integrated circuit device in which a circuit wiring layer is provided on the cap.

[0002]

2. Description of the Related Art Conventionally, a hybrid integrated circuit in which a semiconductor element is mounted in a recess formed in a printed wiring board (hereinafter, simply referred to as a substrate), and the opening of the recess is closed by a cap to seal the semiconductor element. In some circuit devices, the cap is also provided with a circuit wiring layer and surface mount components to form an integrated circuit. For example, (JP-A-5-41570)
The configuration as disclosed in 1) can be mentioned.

The package of this hybrid integrated circuit device comprises a ceramic base formed in the shape of a box with an open top and an open top, and a cap for closing the opening of the top. In the box-shaped ceramic base, electronic circuit wiring conductors are formed on the inner bottom surface thereof and electronic components are mounted. Further, the box-shaped ceramic base has electrodes formed on its upper open surface, and the electrodes are electrically connected to the wiring conductors for electronic circuits formed on the inner bottom surface through the wiring formed along the inner wall surface. ing. A conductive resin or gold bump is applied to this electrode. A conductor for sealing is formed on the upper open surface outside the electrode so as to surround the upper open surface.

On the other hand, the cap that closes the upper opening of the ceramic base is formed by forming an insulating film on the back surface of a thin metal plate. On the insulating film, a wiring conductor for an electronic circuit is formed and an electronic component is formed. I have it implemented. On the back surface of the cap, the insulating film is removed from the outer peripheral portion corresponding to the conductor for sealing the upper open surface.

When a box-shaped ceramic base is sealed with a cap, an electrode formed on the upper open surface of the ceramic base is provided with a conductive resin or gold bump, and then the electronic circuit is formed on the back surface of the cap. The cap is set on the ceramic base so that the wiring conductors abut the corresponding electrodes. Next, the wiring conductors for both electronic circuits of the ceramic base and the cap are electrically connected to each other by heat, ultrasonic waves, pressure, light or the like through the conductive resin or the gold bumps. After electrical connection, welding is performed between the sealing conductor formed on the upper open surface of the ceramic base and the metal portion on the back surface of the cap from which the insulating film has been removed, and the hermetic sealing is completed.

[0006]

However, since the cap and the substrate are electrically connected by the conductive resin or the gold bump and then the hermetically sealed by welding or the like, it is necessary to adhere the ceramic base and the cap to each other. It requires a process, which causes a decrease in production efficiency. Also, since welding is performed, the adhesion between the ceramic base and the cap is
For example, in the case of silver brazing, a high temperature process of about 800 ° C. is required, and the influence on mounted components, especially semiconductor elements cannot be ignored, resulting in a decrease in reliability.

The present invention has been made to solve the above problems, and its purpose is to enable electrical connection between a substrate and a cap to be performed at the same time as hermetically sealing and at a low temperature step. Another object of the present invention is to provide an adhesive structure for a cap of a hybrid integrated circuit device, which can improve production efficiency and reliability.

[0008]

In order to solve the above-mentioned problems, the present invention forms a circuit wiring layer by forming a recess in an accommodating portion in a printed wiring laminated board, and mounting a semiconductor element in the accommodating portion, and accommodating the same. In a hybrid integrated circuit device in which a semiconductor device is sealed by closing a part opening with a cap, a circuit wiring layer is formed on the cap, and the printed wiring laminated substrate and the cap are joined with a sealing material that can be adhered at a low temperature. The gist of the invention is to electrically connect the circuit wiring layer of the printed wiring laminated board and the circuit wiring layer of the cap with a conductive adhesive that can be bonded at a low temperature.

[0009]

Therefore, according to the present invention, both the sealing material and the conductive adhesive provided at the joint between the printed wiring laminated substrate and the cap can be adhered in a low temperature process. It is possible to hermetically seal and electrically connect the circuit wiring layer of the printed wiring laminated board and the circuit wiring layer of the cap at the same time.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the hybrid integrated circuit device of the present invention will be described below with reference to FIG. A printed wiring laminated substrate (hereinafter, simply referred to as a substrate) 10 is formed by laminating ceramic substrates, and each layer is provided with an internal wiring 11 and a via hole 12 that electrically connects each layer. A staircase-shaped accommodating portion 13 is formed in the center of the substrate 10.
The lower staircase surface is the pad surface 13a, and the upper staircase surface is the cap seal surface 13b. Wiring 14 connected to the internal wiring 11 is provided on the pad surface 13a.
A circuit wiring layer 15 is formed on the surface of the substrate 10. A semiconductor element 16 is fixed to the housing portion 13 with a conductive or insulating adhesive 17. The semiconductor element 16 is electrically connected to the wiring 14 of the housing portion 13 by a wire 18. The terminals 20 are attached to the back surface of the substrate 10 via the brazing material 19, and the internal wiring 11 and the via holes 1 are formed.
It is electrically connected to the circuit wiring layer 15 and the semiconductor element 16 formed on the surface of the substrate 10 through the wiring 2.

The cap 30 is made of ceramic, a flange portion 30a is formed so as to extend in the upper peripheral edge portion so as to face the circuit wiring layer 15, and an abdominal portion 30b is formed so as to bulge at the lower end portion. The lower surface of the abdomen 30b of the cap 30 is adhered to the substrate 10 via a sealing material 31 formed on the cap sealing surface 13b. The sealing material 31 is an epoxy resin to which a curing agent and a filler are added, and the sealing material 31 has a low temperature (about 15
It is cured at 0 ° C. to 200 ° C., and the cap 30 and the substrate 1
Join 0. The surface of the cap 30 and the collar portion 30a
Circuit wiring layers 32 and 33 are formed on the back surface, and the circuit wiring layers 32 and 33 are electrically connected by via holes 34 provided inside the cap 30. Cap 3
A surface mount component 35 is mounted on the surface 0 of the circuit wiring layer 32 via solder 36. Collar 3 of cap 30
A thermosetting conductive adhesive agent 37 such as Ag epoxy or Ag silicon is provided between the circuit wiring layer 33 on the back surface of the substrate 0a and the circuit wiring layer 15 formed on the surface of the substrate 10 to electrically connect them. Has been done. The conductive adhesive 37 can be bonded in a low temperature (about 150 ° C. to 200 ° C.) process.

As described above, according to this embodiment, the circuit wiring layer 15 on the surface of the substrate 10 and the circuit wiring layer 33 on the rear surface of the collar portion 30a of the cap 30 are electrically connected, and the lower surface of the abdominal portion 30b of the cap 30 and the cap sealing surface. Since the sealing material 31 and the conductive adhesive 37, both of which can be bonded in the low temperature process, are used for bonding with 13b, these two processes can be performed at the same time. Therefore, the number of steps in the production process is reduced and the production efficiency is increased. Moreover, since the cap 30 is adhered by the conductive adhesive 37 in addition to the sealant 31 and the adhesion area is widened and therefore the adhesive strength is increased, the semiconductor element 16 can be sealed more reliably. Further, by using the conductive adhesive 37 that can be adhered in the low temperature process, the influence on the semiconductor element 16 is reduced and the reliability is improved.

Further, the surface of the cap 30 and the collar portion 30a.
Since the circuit wiring layers 32 and 33 are provided on the back surface and the surface mounting component 35 is further provided on the circuit wiring layer 32, the mounting efficiency can be improved. In order to provide the circuit wiring layers 32 and 33 on the front surface of the cap 30 and the rear surface of the collar portion 30a, the via hole 34 is provided inside the cap 30 in this embodiment. With such a configuration, the cap 3
The original function of encapsulating the semiconductor element 16 is not impaired, and therefore the mounting efficiency is improved without causing a problem such as deterioration of reliability. Further, the surface-mounted component 35 mounted on the surface of the cap 30 can be repaired and replaced even after the hybrid integrated circuit device is manufactured. Therefore, as a result of the reliability test, when a defect occurs, the surface-mounted component 35 is repaired and the product is manufactured. It can be shipped and the yield is improved.

Furthermore, since the step of mounting the semiconductor element 16 on the substrate 10 and the step of mounting the surface mount component 35 on the cap 30 can be performed in parallel, the production efficiency can be improved.

The present invention is not limited to the above embodiment, but may be modified as follows, for example, without departing from the gist of the present invention. (1) In the above embodiment, the sealing material 31 is provided between the lower surface of the belly portion 30b of the cap 30 and the cap sealing surface 13b of the substrate 10, and the conductive adhesive 37 is provided between the rear surface of the collar portion 30a and the front surface of the substrate 10. However, this sealing material 31
The places where the conductive adhesive 37 is provided may be replaced as shown in FIG.

That is, the circuit wiring layer 15 is provided on the upper step surface of the accommodating portion 13 of the substrate 10, and the surface of the substrate 10 serves as the cap sealing surface 13b. A circuit wiring layer 33 is provided on the lower surface of the abdomen 30b of the cap 30 so as to face the circuit wiring layer 15. Then, the cap 30 is bonded on the cap sealing surface 13b of the substrate 10 via the seal material 31, and the circuit wiring layers 15 and 33 are bonded via the conductive adhesive 37. In this embodiment, the conductive adhesive 37
Since the sealant 31 is provided inside the sealant 31, the conductive adhesive 37 is protected from contamination such as oxidation.
The reliability of the electrical connection between 0 and the cap 30 is improved.

(2) In the above embodiment, the circuit wiring layers 32 and 33 on the front surface of the cap 30 and the rear surface of the collar portion 30a are electrically connected through the via holes 34, but the following may be adopted.

As shown in FIG. 3, the circuit wiring layers 32 and 33 on the front surface of the cap 30 and the rear surface of the collar portion 30a are extended toward the end portion and connected to the wiring 38 provided on the side surface of the cap 30. You may make it connect physically. In this embodiment, since the circuit wiring layers 32 and 33 and the wiring 38 can be formed in the same process, the production efficiency can be improved.

(3) In the above embodiment, the cap 30 is formed so that the flange portion 30a faces the circuit wiring layer 15 on the surface of the substrate 10, and the sealing material 31 and the conductive adhesive 37 are respectively provided on the substrate. 10 cap seal surface 13
b, it is provided on the surface of the substrate 10, but it may be performed as follows.

As shown in FIG. 4, the cap 30 is attached to the substrate 1.
The structure may be dropped to 0, and the sealing material 31 and the conductive adhesive 37 may be provided on the cap sealing surface 13b of the substrate 10. In this embodiment, the cap 30 has a simple shape, which facilitates processing. Further, since the thickness of the cap 30 can be reduced, the overall thickness of the hybrid integrated circuit device can be reduced and the size can be reduced. Further, by adopting a structure in which the cap 30 is dropped onto the substrate 10, the positioning of the cap 30 can be accurately performed without using a jig, and the production efficiency can be improved.

(4) Although the surface mount component 35 is provided only on the front surface of the cap 30 in the above embodiment, the surface mount component 35 may be provided on the rear surface of the cap 30 as shown in FIG. At this time, the circuit wiring layers 32 and 33 on the front and back surfaces of the cap 30 are electrically connected not only to the via holes 34 on the end side inside the cap 30, but also directly to the circuit wiring layers 32 and 33 on the front and back surfaces of the cap 30. Such via holes 34 may be provided. With such a configuration, the mounting efficiency can be further improved.

(5) In the above embodiment, the cap 30 is only provided with the via hole 34, but if a more complicated circuit is desired to be formed, it may be arranged as shown in FIG. That is, the internal wiring 39 may be formed inside the cap 30 as in the case of the substrate 10. With such a configuration, since a complicated circuit is formed inside the cap 30, high integration can be achieved.

(6) In the above embodiment, the circuit wiring layers 15 and 33 are provided on the front surface of the substrate 10 and the back surface of the cap 30, respectively. However, instead of the circuit wiring layers 15 and 33, only the electrode pattern is used for the substrate 10 and the cap. Thirty electrical connections may be made.

(7) In the above-described embodiment and the other example of (3), at least the lower portion of the cap 30 has a structure of being dropped into the substrate 10. However, as shown in FIG. May be provided in the.

(8) In the above embodiment, the conductive adhesive 37
Although a thermosetting type is shown as the above, it may be appropriately changed to a room temperature curing type, an ultraviolet curing type or the like depending on the environment in which the hybrid integrated circuit device is used.

(9) Instead of the epoxy resin as the sealing material 31 in the above embodiment, a low melting point glass may be applied. Low temperature (150 ° C-3
Adhesion is possible in the step of 50 ° C.

(10) In the above embodiment, the substrate 10 is formed by laminating the ceramic substrates, but a glass epoxy substrate or a polyimide substrate may be used instead of the ceramic substrate.

[0028]

As described above in detail, according to the present invention, by providing the sealing material and the conductive adhesive which can be adhered at a low temperature together at the joint between the cap and the substrate, the semiconductor element can be sealed. Since the circuit wiring layer of the substrate and the circuit wiring layer of the cap can be electrically connected at the same time and in the low temperature process, the production efficiency and the reliability of the hybrid integrated circuit device can be improved. effective.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a hybrid integrated circuit device of the present invention.

FIG. 2 is a cross-sectional view of the hybrid integrated circuit device in which the positions where the seal material and the conductive adhesive are provided are exchanged.

FIG. 3 is a cross-sectional view of a hybrid integrated circuit device in which circuit wiring layers on a front surface and a back surface of a cap are electrically connected by wiring on a side surface of the cap.

FIG. 4 is a cross-sectional view of essential parts of a hybrid integrated circuit device having a structure in which a cap is dropped onto a substrate.

FIG. 5 is a cross-sectional view of a main part of a hybrid integrated circuit device in which a surface mounting component is also provided on a circuit wiring layer on the back surface of a cap.

FIG. 6 is a cross-sectional view of essential parts of a hybrid integrated circuit device in which internal wiring is provided in addition to via holes inside a cap.

FIG. 7 is a cross-sectional view of essential parts of a hybrid integrated circuit device in which a cap is provided on the surface of a substrate.

[Explanation of symbols]

10 ... Printed wiring laminated board, 11 ... Internal wiring inside the board,
12 ... Via hole inside the substrate, 13 ... Housing portion, 13a ...
Pad surface, 13b ... Cap sealing surface, 14 ... Wiring, 1
5 ... Circuit wiring layer provided on substrate surface, 16 ... Semiconductor element, 17 ... Adhesive agent, 18 ... Wire, 19 ... Brazing material, 20
... terminals, 30 ... caps, 30a ... cap collars, 3
0b ... Cap abdomen, 31 ... Sealing material, 32 ... Circuit wiring layer on cap surface, 33 ... Circuit wiring layer on back surface of cap,
34 ... Via hole inside cap, 35 ... Surface mount component mounted on cap, 36 ... Solder, 37 ... Conductive adhesive, 38 ... Side wiring, 39 ... Internal wiring in cap

Claims (1)

[Claims] 1. A printed wiring laminated board is provided with a recess, a circuit wiring layer is formed, a semiconductor element is mounted on the recess, and the opening of the recess is closed by a cap to seal the semiconductor element. In the hybrid integrated circuit device that has been stopped, a circuit wiring layer is formed on the cap, and the printed wiring laminated substrate and the cap are joined by a sealing material that can be bonded at low temperature, and a conductive adhesive that can be bonded at low temperature A bonding structure of a cap of a hybrid integrated circuit device for electrically connecting a circuit wiring layer of a printed wiring laminated board and a circuit wiring layer of a cap.