JPS6317547A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve adhesive properties on hermetic sealing by loading a semiconductor element onto the upper surface of a connecting pad and joining a cover for coating and sealing a land, a pin and a conductive circuit and the semiconductor element with the outer circumferential section of a substrate without being brought into contact with these land, pin and conductive circuit. CONSTITUTION:Lands 12, a conductive circuit 3 and connecting pads 5 are formed to a flexible substrate, and through-holes A are shaped to the land sections, thus acquiring a flexible wiring board 2. A substrate is disposed onto the lower surface of the flexible wiring board. Through-holes B having diameters larger than the through-holes A are shaped to the substrate at positions corresponding to the through-holes A, and pins are penetrated into the through-holes A, B. The pins and the lands in the periphery of the through-holes A are fixed and connected electrically, a semiconductor element 7 is loaded onto the upper surfaces of the connecting pads, and a cover 8 is joined with the outer circumferential section of the substarte in order to cover and seal the lands, the pins and the conductive circuit and the semiconductor element without being brought into contact with these lands, pins and conductive circuit. Accordingly, adhesive properties on hermetic seal are improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a semiconductor device.

(Conventional technology and its problems) Conventionally, in order to mount a semiconductor element on a printed wiring board,
The most common method was to use a ceramic chip carrier or a ceramic package. However, commonly used high alumina ceramics (
Ceramics (hereinafter referred to as ceramics) have a high dielectric constant of about 9, and therefore are not preferred materials because of the large signal delay in the recent ultra-high-speed calculations. On the other hand, glass epoxy wiring boards have a dielectric constant of about 5 and are less likely to distort signal waveforms due to stray capacitance of wiring than ceramics, but they have lower heat resistance and thermal conductivity than ceramics.

This has the drawback that there is a limit to high density packaging.

On the other hand, attempts have been made to mount a silicon chip directly onto a printed wiring board, but most of them are mounted via a chip carrier, and those with a large number of input/output terminals are packaged in a pin grid array type package. The drawbacks caused by this cannot be avoided.

As an improvement on these, there is a wiring board for mounting semiconductor elements as shown in Japanese Patent Application No. 133916/1982.

However, because there are few exposed parts of the metal plate, the heat dissipation effect of this product is insufficient, and when packaged,
Problems arise with adhesion during hermetic sealing.

The object of the present invention is to provide a semiconductor device free from the above-mentioned drawbacks.

(Means for Solving the Problems) As a result of various studies on the above-mentioned drawbacks, the present inventors have developed a structure of a semiconductor device using a wiring board for mounting semiconductor elements as shown below. form circuits and connection pads.

Furthermore, a through hole (A) is provided in the land portion to obtain a flexible wiring board, and then a substrate (hereinafter referred to as a substrate) on which a conductive circuit is formed on the upper and/or lower surface of the flexible wiring board obtained above is placed on the lower surface of the flexible wiring board obtained above. Arranged.

A through hole (B) with a slightly larger diameter is formed in the substrate at a position corresponding to the through hole (4), and a pin is passed through the through hole (Bl) to form a through hole (B) with a slightly larger diameter. (
5) The surrounding lands are fixed and electrically connected with solder, silver solder, etc., and the semiconductor element is mounted on the top surface of the connection pad, and the semiconductor element is connected to the lands, pins, and conductive circuits without contacting them. When the lid was bonded to the outer periphery of the board to cover and seal the board, the dielectric constant was around 5, lower than that of a ceramic wiring board, and the heat resistance and thermal conductivity were higher than that of a glass epoxy wiring board. It was confirmed that elements with high heat generation density can also be mounted. It also has an excellent heat dissipation effect, and it was confirmed that there would be no problems with adhesion during hermetic sealing when it was made into a pancage.

In the present invention, a substrate is disposed on the lower surface of a 7-lexiple wiring board on which lands, conductive circuits, and connection pads are formed on the upper surface,
Through-hole provided in the land part of the flexible wiring board ■ Insert the pin into the through-hole (B) provided in the board at the position corresponding to the through-hole diagram so that the top surface touches the land part. It sticks.

In addition, a semiconductor element is mounted on the top surface of the connection pad.

The present invention also relates to a semiconductor device in which a lid for covering and sealing lands, pins, and conductive circuits without contacting these and a semiconductor element is bonded to the outer peripheral portion of the substrate.

The flexible wiring board in the present invention is a land on a flexible thin board such as polyimide film, polyester film, polyamide-imide film, etc.

A conductive circuit and a connection pad are formed, and a through hole (3) is provided in the land portion.

The substrates used in the present invention are 5 paper-epoxy laminates and 2-paper phenol laminates, which are made by impregnating a woven fabric or non-woven fabric made of paper, glass fiber, etc. with a resin composition such as epoxy or phenol, and then laminating and curing it.

Printed wiring board materials such as glass epoxy laminates are used depending on the application, and conductive circuits are formed on the top and/or bottom surfaces thereof.

A through-hole formed in the substrate (Bl is formed at a position corresponding to the through-hole diagram when arranged on the bottom surface of a flexible wiring board, and is slightly larger than the diameter of a through-hole formed in a flexible thin plate. It is preferable to form a through hole (B) of
Further, it is preferable to form a conductive layer on the peripheral wall of the through hole (B) of the substrate, because when fixing the conductive layer to the pin, the same material used for fixing to the land formed on the flexible thin plate can be used for fixing.

The pin does not require any special material; it is made of copal.

42 alloy, 52 alloy, etc. are used, and the length is so that it protrudes from the bottom surface of the board to which it is inserted and fixed.

It is preferable to use one that is longer than the combined thickness of the flexible wiring board and the substrate, and it is preferable that the protrusion length is 1 or more.

The pins are fixed to the flexible wiring board and the board using solder.
It is preferable to fix it using silver solder or the like.

In addition, the pins and the board may be fixed using a resin, and the applicable resins include thermosetting resins such as epoxy resins and polyimide resins, and heat-resistant thermoplastic resins, depending on the application and usage conditions. used. Furthermore, in the present invention, AI! is added to these resins. It is preferable to mix a filler with good thermal conductivity, such as N or BN, because it provides excellent heat dissipation.

The lid covers the lands, pins, and conductive circuits so that they do not come in contact with them, and is bonded to the outer periphery of the substrate. However, the lid may contact and cover the semiconductor elements mounted on the top surface of the connection pads. Although there is no limitation, it may be covered without contacting the semiconductor element, but it is preferable to contact the upper surface of the semiconductor element because heat dissipation is excellent.

It is preferable to use a metal with excellent thermal conductivity, such as copper or a copper alloy, as the material of the lid, since it can be collapsed for heat dissipation. Further, as a material for joining, a brazing material may be used for joining, silicone resin, polyimide resin.

A thermosetting resin with excellent heat resistance such as an epoxy resin may be used for bonding, and a bonding material suitable for the purpose and usage conditions is used.

Although there are no particular restrictions on the material for forming the lands, conductive circuits, and connection bands, it is preferable to use steel in terms of cost, thermal conductivity, and the like. For example, it may be formed using a flexible thin plate, a copper foil pasted on the surface of a substrate, or a plating process.

(Function) The semiconductor device of the present invention uses a flexible thin plate such as polyimide film or polyamideimide film as a material for forming the flexible wiring board, so the dielectric constant is lower than that of a ceramic wiring board, and glass epoxy wiring is used. You will get something almost identical to the board.

Further, since the substrate is disposed on the lower surface of the flexible wiring board, the thermal conductivity and heat dissipation effect are improved due to the conductive circuit of the substrate.

Furthermore, by bonding the lid to the substrate, the heat dissipation effect is further improved.

(Example) The present invention will be explained below with reference to Examples.

Example 1 A piece of polyimide film with dimensions of 30 x 30 mm and a thickness of 0.254 mm was laminated with a copper foil of 18 μm in thickness, a resist film was formed on the upper surface of the copper foil, and etching was performed.
The resist film is peeled off to form a conductive circuit 3 as shown in FIG. A diameter of 0.6 is provided in the area excluding the connection pad 5 for bonding the semiconductor element and the central part (dimensions 8 x 811n).
A land 12 of ff1m is formed, and a connection pad 5.
Solder resist (manufactured by Taiyo Ink Manufacturing, product name FO
C800G) 6 is applied, and then a through hole (A) with a diameter of 0.5 mm is formed in each land 12 by punching.
A flexible wiring board 2 was obtained in which 72 pieces of No. 14 were provided.

On the other hand, as shown in Fig. 2, a double-sided copper-clad laminate 1 (a double-sided copper-clad laminate 1 (
When a hole (manufactured by Shin-Kobe Denki, product name B665) is placed on the bottom surface of the flexible wiring board 2, a diameter of 0.6
A through hole (Blll) with a diameter of mm was formed using a carbide drill. After that, a resist [1] was formed on the upper surface of the steel foil, etching was performed, and the resist film was peeled off to form a conductive layer 17, a conductive circuit 18 and a conductive circuit 18 as shown in FIG. Lands 19 are formed, and the same solder resist 13 as described above is applied between the conductive circuit 18 portion on the lower surface and between adjacent lands 19 on the lower surface.

Then conductive layer 17. Conductive circuit 18 and land 1 on top surface
Part 9 was plated with nickel to a thickness of 7 μm.

Next, as shown in FIG.
5 with a length of 6 mm and one end shaped like a nail head.
After inserting the rad pin 4 into the nail of the 2 alloy into the through hole (A) 14 and the through hole (Bllll) and exposing the other end (terminal) to the bottom surface, insert the rad pin 4 and the land 12 into the nail.
and the conductive layer 17 were fixed with a solder of Sn:Pb=63:37 to obtain a wiring board for mounting a semiconductor element. Thereafter, as shown in FIG. 4, the connection pads 5 and the semiconductor element 7 with dimensions of 3 x 4 mm are connected to each other with dimensions of 0. IX0. I x height 0.
Bonding was performed using a 5 mm semicircular cylinder of Sn:Pb=5:95.

On the other hand, as shown in Figure 5, the dimensions are 60 x 60 mm and the thickness is 0.
．． A protrusion 10 with a height of 1.3 an and a radius of curvature of the processed part of 0.5 mm R and dimensions of 32 x 32 mm is formed in the center of the copper plate 5- by drawing, and the outer periphery is cut into dimensions of 39 x 39- to form a lid. I got 8. Next, nickel plating was applied to the surface of the lid 80 to a thickness of 2 μm using a Watt bath.

Next, a part of the lid 8 is brought into contact with the upper surface of the semiconductor element 7, and the outer periphery of the lid 8 is aligned with the outer periphery of the double-sided copper-clad laminate 1 and bonded using solder 9 of Sn:Pb=63:37. As a result, a semiconductor device shown in FIG. 5 was obtained.

When we measured the thermal conductivity and dielectric constant of the obtained semiconductor device, we found that the thermal conductivity of the part where the semiconductor element was mounted was 0, 4 s cal/cm · sec 'c, and the heat generated from the semiconductor element was transferred to the bottom and top surfaces. The dielectric constant was 5.5, which was almost the same as that of a glass epoxy wiring board. The thermal conductivity and dielectric constant are measured by JI
It was carried out according to SC2141.

In addition, a socket (not shown) K for inserting RAD pins 4 with no load into the 72 nails exposed from the wiring board for mounting semiconductor elements.
After insertion, the nail head pin 4 was inserted and fixed in the socket by operating the lever.

When the Rad pin 4 is inserted into the nail, distortion occurs in the Rad pin 4, but even if this operation of inserting the Rad pin 4 into the nail is repeated 100 times, the flexible wiring board 2 and the semiconductor element 7 are still bonded. No cracks or other fractures occurred in the solder pillars.

Further, the semiconductor device obtained above was subjected to a pressurization test at 120° C. and 2 atm (gauge pressure) for 100 hours, but no breakage or corrosion of the conductive circuit inside the lid was observed.

Comparative Example 1 A double-sided copper-clad laminate (manufactured by Shin-Kobe Electric Machinery Co., Ltd.) in which copper foil with a thickness of 18 μm was laminated on both sides of a glass nonwoven fabric composite laminate with dimensions of 40×40 mm and a thickness of 1.0 on.

(product name: E665) except for the center part (dimensions 8 x 8 mm) with a carbide drill at 2.54 mm intervals.
72 through holes were provided. Thereafter, copper plating was applied to both surfaces and the through holes to a thickness of 10±2 μm using the etched foil method, a conductive layer was formed in the through holes 9, and then a resist film was formed on the surfaces and etched.

The resist film is peeled off and a predetermined conductive circuit is formed on the top surface.

Width 0, 3 on the outer periphery of the connection pad and through holes on the upper and lower surfaces.
A substrate was obtained in which lands of an were formed and these were made electrically conductive.

Next, insert the rad pin into the nail through the above through hole.

The nail head pin and the above board are Sn:Pb=63:3.
It was fixed with solder number 7. Thereafter, the connection pads and the semiconductor element were bonded together in the same manner as in Example 1.

After that, when the thermal conductivity and dielectric constant were measured in the same manner as in Example 1, the dielectric constant was 5.2, which was almost the same as that of the glass epoxy wiring board, but the thermal conductivity of the part where the semiconductor elements were mounted was The heat generated from the semiconductor element at a rate of 0.07 cat/am·sec·° C. can be radiated from the top surface, but heat radiation from the bottom surface is poor and good heat radiation performance cannot be obtained.

Furthermore, when strain was repeatedly applied to the rad pin to the nail in the same manner as in Example 1, cracks appeared in the solder pillars connecting the substrate and the semiconductor element after only 5 times of edge bending, and electrical continuity could not be ensured. There wasn't.

In addition, in Comparative Example 1, a defect occurred before the lid was joined, so
No work was performed to bond the lid to the outer peripheral portion of the substrate.

In the embodiment of the present invention, the lid has a flat top surface, but as shown in FIG.
If 9M16 is used, the heat dissipation effect will be even better, so it is preferable.

(Effect of the invention) The semiconductor device according to the present invention has a dielectric constant and a thermal conductivity.

This semiconductor device has excellent heat dissipation effects and mechanical strength, and has no problems with adhesion when joining the lid.゛

[Brief explanation of drawings]

1, 2, 3, 4, and 5 are cross-sectional views showing the state of manufacturing work of a semiconductor device in one embodiment of the present invention, and FIG. 6 is another embodiment of the present invention. FIG. 2 is a cross-sectional view of a lid used in a semiconductor device. Explanation of symbols 1... Double-sided steel clad laminate 2... Flexible wiring board 3... Conductive circuit 4... Rad pin to nail 5
...Connection hat 6...Solder resist 7...
・Semiconductor element 8...Lid 9...Half 1) 10...Protrusion 11...Through hole (B) 12...Land 13...Solder resist 14...Through hole (3) 15 ...Bending part
16... Lid 17... Conductive layer 18...
・Conductive circuit 19...Rand 嘱/K'$ 3 Figure

Claims (1)

[Claims] 1. A substrate with a conductive circuit formed on the top and/or bottom surface is disposed on the bottom surface of a flexible wiring board with a land, a conductive circuit, and a connection pad formed on the top surface, and a substrate is provided on the land portion of the flexible wiring board. A pin is inserted and fixed into the through hole (A) provided in the through hole (A) and the through hole (B) provided in the board at a position corresponding to the through hole (A) so that the top surface is in contact with the land portion, and the top surface of the connection pad is A semiconductor device in which a semiconductor element is mounted on the substrate, and a lid is bonded to the outer periphery of the substrate to cover and seal the semiconductor element and the semiconductor element without contacting the lands, pins, and conductive circuits.