JPS6076146A - Thin type semiconductor device - Google Patents

Abstract

PURPOSE:To manufacture a thin type semiconductor device available for a desk- top calculator, a card, etc. easily by interposing a semiconductor element between two adhesive films, in which a thermoplastic resin is applied on heat- resistant films as a fusing agent and sealing the element by both adhesive films. CONSTITUTION:A printed circuit board 1 is placed on adhesive films 4 while a semiconductor element 5 is set into a through-hole 2, and these circuit board 1 and element 5 are bonded and fixed to the adhesive films 4 by the heat sealing properties of a fusing agent 4b. The element 5 and the circuit board 1 are wire- bonded by using bonding wires 6, and adhesive films 3 are fitted on these element 5, circuit board 1 and bonding wires 6 and the films 3 are bonded and applied by the heat sealing properties of the fusing agent 3b. Accordingly, sealing work is facilitated extremely because the semiconductor element 5 is bonded and fixed while it can be sealed with a resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin semiconductor device in which a semiconductor element is thinly packaged.

In recent years, there has been a trend for trains, cards, etc. to become thinner from the viewpoint of practicality, and when incorporating semiconductor elements inside these products, it is required to package them as thinly as possible. Ceramic sealing, epoxy resin sealing, and the like are known as conventional packaging means, but such means do not fully meet the above requirements.

From the above viewpoint, the present invention aims to provide a thin packaged semiconductor device that meets the above requirements, and the gist thereof is to coat a heat-resistant film with a thermoplastic resin as an adhesive. A thin semiconductor device characterized in that a semiconductor element is interposed between two adhesive films, and the element is sealed with both of the adhesive films.

This invention will be explained below with reference to the drawings.

The drawing is a sectional view of a main part showing an example of a thin semiconductor device of the present invention.

In the figure, 1 is a printed circuit board formed by forming a predetermined printed circuit on a circuit board such as a copper-clad laminate having through holes 2, and 3 and 4 are provided in through poles 2 of the circuit board 1. This is an adhesive film formed by attaching and supporting the semiconductor element 5 from both sides thereof, and each of the films 3 and 4 is a heat-resistant film 3a.

4a and fusing agents 3b and 4b made of a thermoplastic resin coated thereon by solution coating or melt coating. A bonding wire 6 electrically connects the element 5 and the printed circuit board l.

The semiconductor device having the above structure can be assembled as follows. First, the printed circuit board 1 is placed on the adhesive film 4, and the semiconductor element 2 is set in the through hole 2, and the circuit board I and the element 2 are adhesively fixed to the adhesive film 4 by the thermal adhesive properties of the adhesive 4b. do. Next, after wire bonding is performed between the element 2 and the circuit board 1 using the bonding wire 6, an adhesive film 3 is provided on the element 21 circuit board l and the bonding wire 6, and the adhesive film 3 is thermally fused with the adhesive 3b. Adhesive coating depending on the nature. As a result, the element 2 is firmly adhered and supported within the through hole 2 by the adhesive films 3 and 4 on both sides, and is in a sealed state insulated from the external atmosphere by both films 3 and 4.

Thus, according to the present invention, two adhesive films 3
, 4 was used as the fusing agent ab for this film.

By heating to a temperature equal to or higher than the melting point of Ilb, the semiconductor element 2 can be adhesively fixed and sealed with resin at the same time, making the sealing work very easy. Furthermore, since this sealing can be performed using two adhesive films, a thin package is possible and the above-mentioned requirements can be fully met.

Further, the adhesive films 3 and 4 are heat-resistant films 3a and 4.
Since 3.a is used as a base film, it provides good heat resistance during the assembly and use of the semiconductor device. Since b and 4b enable uniform and strong adhesion to the semiconductor element 2, etc., good results can also be obtained in preventing moisture from entering the surface of the semiconductor element.

As the heat-resistant films 3a and 4a in the adhesive films 3 and 4 of the present invention, polyimide films are typically used. Other films such as polytetrafluoroethylene may be used as long as they have heat resistance higher than the fusion temperature of the thermoplastic resin constituting the low fusion agents 3b and 4b.

Further, the thermoplastic resin constituting the fusing agents 8b, 4b is preferably a fluorine-based polymer having a melting point of 200 to 320'C, and other thermoplastic resins having the same melting point as above can be used. If the melting point is too low, problems tend to occur in the heat resistance of the semiconductor device, and if the melting point is too high, high temperatures are required for bonding, both of which are unfavorable.

It is preferable that 3b and 4b to be fused have the same fusion temperature, or that fusion agent 4b has a higher fusion temperature than 3b. In the opposite case, thermal flow of the adhesive 4b that has already been bonded and solidified occurs when the adhesive sheet 3 is bonded, which may cause displacement of the element 2, which is not preferable.

The fluorine content of the above fluorine-based polymer is usually 20
The amount used is at least 50% by weight, preferably from 50 to 76% by weight. In particular, homopolymers or copolymers of perfluoroalkenes or perfluorovinyl ethers are suitable, and a representative example thereof is tetrafluoroethylene-hexa7/L/opropylene copolymer (hereinafter referred to as F
(referred to as EP) structural formula; (CF2-CF2-CF2-C
F, (ORf) J, (in the formula, Rf has 7 carbon atoms
Hereinafter, a tetrafluoroethylene-perfluorovinylether copolymer (hereinafter referred to as PFA) represented by (preferably meaning 1 to 3 fluorinated alkyl groups) can be mentioned. Commercial products of the above PFA include Neoflon PFA (trade name) manufactured by Daikin Industries, Ltd. and Teflon PFA (trade name) manufactured by DuPont.

Other examples of the above-mentioned fluorine-based polymers include those in which part of the fluorine in PFA represented by the above structural formula is replaced with hydrogen, polychlorotrifluoroethylene, and ethylene-tetrafluoroethylene copolymer (hereinafter referred to as ETFE).
, ethylene-chlorotrifluoroethylene copolymer, etc. can also be used.

These fluoropolymers are non-adhesive at room temperature, but when heated above their melting point, they easily fuse to metals, etc., and they also have the characteristic that there is little polymer flow when melted ( ,ing.

The thickness of the adhesive films 3 and 4 is generally 20 lt.
n] or more, preferably 807 zm or more and 100 pm or less, among which the thickness of the heat-resistant films 8a and 4a is 1
The thickness of the thermal adhesive layers 8b and 4b is 5 to 90 μm 1 to 5 to 25 μm
It is μm.

As described above, according to the present invention, a thin semiconductor device applicable to calculators, cards, etc. can be easily manufactured.

Example 1 Melting point 270 on polyimide film 251 tm thick
A polyimide adhesive film was prepared by applying FEP at a temperature of °C to a thickness of lθμmn. Next, a semiconductor memory element (64K MOS DRA) set on a predetermined printed circuit board is
M) was adhered and fixed using the above-mentioned method using two of the above-mentioned adhesive films and simultaneously sealed to obtain a thin semiconductor device as shown in the drawing.

In addition, the bonding conditions are 350℃ with heat pressure bonding from the FEP side.
The conditions were 'C, 5Kg/7 + 5 seconds.

Example 2 Melting point 805 on polyimide film 25 pm thick
I) FA of 'C was applied to a thickness of 10 μm to prepare a polyimide adhesive film. Using this film, a thin semiconductor device was manufactured in exactly the same manner as in Example 1.

Example 3 On a 25 ltm thick polyimide film, a melting point of 2
A polyimide adhesive film was prepared by applying 60'C(7)E"rF E to a thickness of 1 O/7111. Using this film, a thin semiconductor device was made in exactly the same manner as in Example 1.

From Examples 1 to 3 above, it can be seen that thin semiconductor devices useful for calculators, cards, etc. can be easily manufactured.

[Brief explanation of the drawing]

The drawing is a sectional view of a main part showing an example of a thin semiconductor device of the present invention. 3.11...adhesive film, 8a, 4a...heat-resistant film, 8b, 4b...fusing agent, 5...semiconductor element. Patent applicant: Nitto Electric Industry Co., Ltd. Agent: Kunio Negimoto, patent attorney

Claims (1)

[Claims] fl+ A semiconductor element is interposed between two adhesive films made by coating a heat-resistant film with a thermoplastic resin as a fusion agent, and the element is sealed with both of the adhesive films. Characteristic thin semiconductor device. (2) The thin semiconductor device according to claim (1), wherein the heat-resistant film is made of polyimide-based Lylum. (3) A thin semiconductor device according to claim 1 or (2), in which the thermoplastic resin is a fluorine-based polymer having a melting point of 200 to 320°C. (4) The fluorine-based polymer is a perfluoroalkene or Homopoly of perfluorovinyl ether