JPS6240749A - Pin grid array - Google Patents

Abstract

PURPOSE:To reduce the thickness and the cost of a pin grid array by using a circuit board and sealingly molding the board integrally with pins and a heat sink with a mold. CONSTITUTION:The heads of stepped pins 2 are engaged with through holes 7 of a circuit board 1, the pins 2 are calked with the heads 2b of the pins 2 to be secured to the board 1, and a wiring pattern and the pins 2 are simultaneously electrically connected. The board 1 is disposed in a cavity 17 of a lower mold 15, a heat sink 3 is set to coat the hole 5 of the board 1, an upper mold 18 is then moved down to close the molds, heat resistant resin is injected to the cavity 17, sealed and molded to be manufactured.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to pin grid arrays.

(Prior art) Traditionally, dual in-line packages (hereinafter referred to as DIPs) have been the most popular semiconductor device package, but recently, LSI chips have become more highly integrated, and electronic devices have become smaller and more sophisticated. The number of pins in devices has increased due to increasing demands on devices, and since there is a limit to increasing the number of pins in DIP, recently a pin grid array, which has multiple rows of pins on a ceramic substrate, has been developed and put into practical use. It has been provided.

(Problems to be solved by the invention) However, since conventional pin grid array packages use ceramic substrates, they are expensive, and it is difficult to increase the size of the substrate and miniaturize the circuits. There is a problem. For this reason, relatively inexpensive plastic pin grid arrays have been developed using printed wiring board technology, but high precision cannot be obtained without strict control during the manufacturing process. If a metal heat sink was incorporated to increase the heat dissipation, there were problems such as an increase in manufacturing processes such as bonding and sealing of joints.

(Means for Solving the Problems) As a means for solving the above-mentioned problems, the present invention provides a wiring board in which a wiring pattern is formed on the surface of a plastic base film having an opening, and A plurality of pins connected to the wiring pattern and a peripheral edge of a metal heat sink placed on the wiring board so as to cover the opening of the wiring board are sealed and integrated with a heat-resistant resin. Shino provides a pin grid array characterized by:

(Function) The present invention improves the reliability of the pin grid array by encapsulating and molding the wiring board, pins, and heat sink, and at the same time, simplifies the manufacturing process and reduces costs. The wiring board made of a plastic base film contributes to the thinning of semiconductor devices, and the heat sink functions as a heat sink and is attached to the surface of the heat sink exposed through the opening of the wiring board. In addition, the heat-resistant resin seals the wiring board together with the heat sink and pins, contributing to improved mechanical strength, thermal shock resistance, processing accuracy, and simplified manufacturing process. Zuro.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

In the diagram showing an embodiment of the pin grid array according to the present invention, 1 is a wiring board made of a base film made of a plus deck material such as polyimide resin or epoxy resin, 2 is a pin made of a highly conductive metal material, and 3 is copper. Alternatively, the heat sink is made of a metal material with good heat conductivity such as aluminum, and 4 is a sealing part that integrally seals the wiring board, the pins, and the heat sink, and is made of a heat-resistant resin such as polyphenylene sulfide or epoxy resin.

The wiring board l has an opening 5 in the center thereof, and a wiring pattern 6 extending radially from the vicinity of the opening 5 is formed on the surface of the base film, as shown in FIG. A plurality of through holes 7 are formed through the base film and the wiring pattern 6.

In the pin grid array according to the present invention, since the wiring board l is formed of a thin plastic film, the bonding strength between the wiring board and the wiring pattern is low, so even if the wiring pattern and the pins are soldered, the strength is low. no improvement,
Moreover, in interviews using soldering, soldering requires complicated processing and requires a cleaning process after processing. While the wiring pattern 6 around the hole 7 is formed in a ring shape, a large-diameter stepped portion 2a is formed near the head side of the pin 2 to be inserted into the through hole 7, and the head 2b is formed to pass through the wiring board l. After inserting into the hole 7, the pin 2 is fixed to the wiring board 1 by caulking with a hammer ring or the like, and the wiring board ■ is held between the head part 2b and the stepped part 2a, and the pin 2 is connected to the wiring pattern 6. I try to do that.

The heat dissipation plate 3 has a recess 9 having approximately the same area as the opening 5 on the side facing the opening 5 of the wiring board l, and a peripheral edge 3a.
A protrusion! 0 is formed, and by sealing and molding the peripheral portion 3a with the wiring board 1 and the pins 2 with heat-resistant resin, the wiring board l is formed.
and is integrated with pin 2. In addition, 11 is a standoff, which is used to leave a certain distance between the pin grid array and the mother board when it is attached to a pin socket, mother board, etc., and can be sealed at any position on the pin grid array. It is integrally molded with the stop portion 4.

Further, a hole I2 reaching the head 2b of the pin 2 is formed in the sealing portion 4, and this hole 12 is formed by a movable pin 19 that suppresses and fixes the pin 2 during encapsulation molding. Reference numeral 20 denotes a moisture-proof protective film, which is formed by coating with epoxo-based or polyimide-based resin.

The pin grid array having the above structure can be manufactured as follows. That is, the stepped head 2b of the pin 2 prepared in advance is inserted into the through hole 7 of the wiring board l, and the pin 2 is crimped onto the head 2b of the pin 2 by vibration or hammering, and the pin 2 is attached to the wiring board l. At the same time, the wiring pattern and pin 2 are electrically connected. As shown in FIG. 3, this wiring board I is placed in the cavity 17 of the lower mold 15, and after setting the heat sink 3 so as to cover the opening 5 of the wiring board I, the upper mold I8 is lowered. It can be manufactured by closing the mold, injecting heat-resistant resin into the cavity 17, and enclosing it.

In the manufacturing of wiring boards, the base film is first slit, then degreased and dried. Catalyst paste is applied to the entire surface of the base film to facilitate the adhesion of chemical copper plating. After drying, stamping is performed. , screen print resist ink on areas other than those where the wiring pattern 6 is to be formed to mask them, then apply copper plating using a chemical copper plating method, and layer electrolytic copper plating and electrolytic silver plating on the copper plating. Although it is preferable to form a wiring pattern by using a method of manufacturing a wiring pattern 6 to form a smooth wiring board with no unevenness between the surface of the wiring pattern 6 and the resist ink layer, it is preferable to manufacture the wiring board in the same manner as a known method for manufacturing a flexible printed wiring board. You can also do it.

The present invention is not limited to the embodiments described above, but may be modified in various ways. For example, in the above embodiment, a pin having a single step on one end is used as the stepped pin 2, but as shown in FIG. The wiring board l is caulked between the step 2a on the side of the head 2b and the head 2b, while the space 2C formed between the step 2a and the step 2a' on the lower side is The pulling force of the pin 2 can be further improved by wrapping the heat-resistant resin around it.

Further, a metal ring surrounding the through hole is formed on the surface of the wiring board l opposite to the wiring pattern 6, and the metal ring is used to connect the head of the pin 2 and the stepped portion 2a together with the base film and the wiring pattern 6. It is also possible to sandwich the pin 2 between them so that the pin 2 can be more firmly attached.

Furthermore, in the embodiment, one opening 5 is provided in the wiring board l.
However, as shown in FIG. 5, two or more openings 5 are provided, and each opening 5 is Semiconductor chips can be respectively mounted on the surface of the heat sink 3 exposed from the inside.

(Effects of the Invention) As is clear from the above description, according to the present invention, a wiring board is used and the wiring board is integrally molded with the pins and the heat sink using a mold. It is possible to reduce the thickness and cost of the grid array, and to manufacture a highly reliable pin grid array with high dimensional accuracy of about 50 μm. In addition, since the sealing part and the heat sink are integrated with the wiring board, it is possible to manufacture pin grid arrays with excellent bending strength, mechanical shock resistance, and thermal shock resistance, as well as excellent heat dissipation properties. Effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the pin grid array according to the present invention, FIG. 2 is a plan view of a wiring board used in manufacturing the pin grid array according to the present invention, and FIG. 3 is a cross-sectional view of the pin grid array according to the present invention. FIG. 4 is a partial sectional view of a pin grid array showing another embodiment of the invention, and FIG. 5 is a bottom view of the pin grid array showing another embodiment of the invention. 1 ~ Wiring board 2 ~ Stepped pin 3 ~ Heat sink, 1 ~ Heat resistant resin 5 ~ Opening 6 ~ Wiring pattern 7 ~ Through hole 10 ~ Protrusion Patent Applicant Dai-Seiko Co., Ltd. Agent
Patent attorney: Mr. Hajime and 2 others Go to Figure 3, Figure 4, Figure 5

Claims (1)

[Claims] (1) A wiring board formed by forming a wiring pattern on the surface of a plastic base film having an opening, a plurality of pins erected on the wiring board and connected to the wiring pattern, and an opening in the wiring board. A pin grid array characterized in that it is formed by sealing and integrating with a heat-resistant resin the peripheral edge of a metal heat sink placed on a wiring board so as to cover it.