JPS61179560A - Composite printed wiring substrate for mounting semiconductor element - Google Patents

Abstract

PURPOSE:To obtain a printed wiring substrate easily at low cost by laminating an insulating substrate for a surface layer, to one surface of an inner layer substrate thereof a hole larger than a semiconductor-element housing hole, a hole for preparing a copper foil lead wire and a reference hole are bored and which has a resin outflow preventive frame, with an insulating substrate for a bottom plate, to another surface thereof a hole for preparing the copper foil lead wire and a reference hole are bored. CONSTITUTION:With an inner layer substrate 11, a semiconductor-element housing hole 12, holes 21 for preparing copper foil lead wires 22 and reference holes 13 are bored to an electric insulating substrate made of a synthetic resin on which adhesives are applied, copper foils are thermocompression-bonded with adhesive applying surfaces and the copper foils and the insulating substrate are bonded completely, and conductor circuits 14 and the copper foil lead wires 22 are formed into the holes 21 for preparing the copper foil lead wires. A hole 16 larger than the semiconductor-element housing hole 12, the same holes as the holes 21 for preparing the copper foil lead wires and the reference holes 13 are bored in an insulating substrate 17 for a surface layer, and adhesives having no fluidity are applied onto one surface and the reference holes 13 and holes 21 for preparing the copper foil lead wires are shaped in an insulating substrate 15 for a bottom plate. These substrates are laminated through heating and pressing on the basis of the reference holes 13.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a composite printed wiring board for mounting semiconductor devices, and more specifically, it relates to an insulating substrate having storage holes for storing semiconductor devices such as ICs and LSIs. Composite for mounting semiconductor elements with a structure in which a frame to prevent the sealing resin used to seal the semiconductor elements from leaking out and an insulating plate that also serves as a resin coat to prevent moisture absorption between the conductors. This invention relates to printed wiring boards.

<Conventional technology and its problems> Traditionally, ceramic substrates or synthetic resin steel-clad laminates have been used as small electric circuit boards for electronic wristwatches, electronic desk calculators, electronic cameras, etc. A method has been implemented in which a circuit is formed, a semiconductor element such as an IC or an LSI is mounted on the substrate, and the semiconductor element and the circuit on the substrate are connected with a thin wire made of gold, aluminum, or the like.

However, there is an increasing demand for thinning of this type of electronic equipment, and for this reason, a method of reducing the thickness by embedding a part of the semiconductor element in the substrate is being adopted.

As shown in FIG. 1, the storage hole 2 for storing such a semiconductor element has conventionally been created after a circuit 3 is created on the insulating substrate 1 made of a copper-clad laminate. It was machined at a predetermined position so as not to penetrate to the back surface of the insulating substrate 1.

However, in this case, the conductor circuit around the hole may peel off during drilling, and the bottom corner of the hole cannot be cut properly, making it difficult to accurately determine the depth of the hole. There were problems such as high processing costs due to poor quality.

Furthermore, the semiconductor elements connected to the insulating substrate 1 are sealed with epoxy resin or the like in order to protect them from mechanical shock and environmental conditions such as humidity, dirt, and temperature. In order to prevent the leakage of the resin liquid used for this purpose, it is necessary to provide a leakage prevention frame 4 around the semiconductor element to be sealed, and to prevent the electrical insulation from deteriorating due to moisture absorption between the conductor circuits, epoxy resin, etc. This has the disadvantage that the process becomes extremely complicated.

Means for Solving the Problems> The present invention was obtained as a result of studies to eliminate all the drawbacks of the conventional circuit boards as described above. A printed wiring board for mounting semiconductor elements is made inexpensive and has an insulating board for the surface layer on the circuit board, which has a frame to prevent the resin from flowing out and a coating resin to prevent moisture absorption between the circuits mounted on the board. It is intended to be provided easily.

<Example> An example of the present invention will be described below based on FIG. 2 showing the manufacturing process.

Figure 2 shows L, which was conventionally made using ceramic etc.
The SI flat package is obtained by laminating a synthetic resin electrically insulating substrate, and Figure (1) is a partial cross-sectional view.
(It) is a plan view thereof.

In the figure, 11 is an inner layer substrate, and this inner layer substrate 11
A synthetic resin electrically insulating substrate on which a non-flowable adhesive (not shown) has been applied on one side in advance has a semiconductor element housing hole 12, a copper foil lead wire 22 forming hole 21, and a reference hole 13.
After punching the holes 21, the copper foil is thermocompressed onto the adhesive-coated surface to completely adhere the copper foil and the insulating substrate, and then etching resist ink or the like is filled into the hole 21 for creating the copper foil lead wire, and etching is performed. After forming the conductor circuit 14 and the copper foil lead wire 22, the etching resist ink was removed, and if necessary, plating with gold, nickel, silver, etc. was performed.

Reference numeral 17 denotes an insulating substrate for the surface layer, and in this substrate 17, a hole 16 larger than the semiconductor element storage hole 12, a hole the same as the hole 21 for making a copper foil lead wire, and a reference hole 13 are drilled using a hammering method.

Further, the insulating substrate 15 for the bottom plate is coated with a non-flowable adhesive (not shown) on one side thereof, and is provided with a reference hole 13 and a hole 21 for forming a copper foil lead wire.

Next, the surface layer insulating substrate 17 is attached to the upper surface of the inner layer substrate 11, and the bottom plate insulating substrate 15 is bonded to the lower surface of the inner layer substrate 11 by heating and pressing based on the reference hole 13, thereby forming the semiconductor element housing hole 12. A composite printed wiring board for mounting a semiconductor element of the present invention having a resin outflow prevention frame 19 for sealing a semiconductor cord and a copper foil lead wire 22 is obtained.

The composite board according to this example is obtained by mounting a semiconductor element, connecting it to the board conductor by wire bonding, sealing the semiconductor element with resin, and cutting the tip of the copper lead wire by a hammering process. Because it will be done,
LSI flat packages, which were conventionally made of ceramic or the like, can be manufactured extremely easily and at low cost using synthetic resin electrically insulating substrates.

The type of synthetic resin electrical insulating substrate or synthetic resin tape material used in the present invention is not particularly limited, and includes, for example, an epoxy resin glass base laminate, the same tape material, a polyimide resin glass base laminate, and the same tape. In addition to polyimide resin tape, triazine resin glass base laminates, tape materials, etc., phenolic resin paper base laminates, epoxy resin paper base laminates, thermoplastic resin sheets,
Molded products are used.

Furthermore, the thickness of the synthetic resin insulating substrate can be selected arbitrarily;
．． Taking the case of mounting a 2# thick semiconductor element as an example, it is appropriate that the copper-clad insulating substrate 11 as a circuit board has a thickness of 0.2#, which is equal to the thickness of the semiconductor element, and the bottom plate insulating substrate 15 has a thickness of 0.2#, which is equal to the thickness of the semiconductor element. It is preferable that the insulating substrate 17 for the surface layer be as thin as possible, such as 0.05 to 0.075 m thick, and by using a 0.2 m thick one, the semiconductor element (
The total thickness of the composite printed wiring board after mounting the LSI chip (LSI chip) is 0.5 #, making it possible to make the board as thin as the thickness of the semiconductor element, including wires for honding.

Inner layer substrate 11, bottom plate insulating substrate 15, and surface layer
'The adhesive used for bonding the insulating substrate 17 is not particularly limited, but if the adhesive flows during the bonding process, the semiconductor element housing hole, the inside of the sealing resin leakage prevention frame, the component mounting hole, etc. may be filled with the adhesive. It is essential that the adhesive does not flow, as there is a risk of the adhesive flowing, and suitable adhesives include butyral phenol resin, a mixture of butyral phenol resin and epoxy resin, a mixture of nylon and butyral phenol resin, and nylon and butyral resin and epoxy resin. A mixture of these or various heat-sealable films are preferred.

In the present invention, the copper-clad laminated insulating substrate, the insulating substrate for the bottom plate, and the insulating substrate for the surface layer are laminated continuously by matching the reference holes drilled in each substrate, and using a hot roll at a pressure of 20 to 40 to'j4.150~1
It is sufficient to carry out hot pressing for 30 minutes under pressure and heat at 80°C, and if necessary, after-cure may be performed at 150'C for 2 to 4 hours.

Another advantage of the composite printed wiring board for semiconductor device mounting according to the present invention is that mounting of semiconductor devices, casting of sealing resin, curing of the resin, inspection, etc. can be performed automatically, which greatly improves production efficiency. It is.

That is, a plurality of circuits or more are formed on an insulating substrate, and an insulating substrate for the bottom plate and an insulating substrate for the surface layer are bonded to this as described above to form a continuous long composite substrate, which is then cut to the required length. The semiconductor devices are loaded one by one onto a conveyor from the bottom, and semiconductor elements are mounted and wire bonded based on the reference holes. In the next process, sealing resin is continuously injected, and then sent to a curing furnace. By finally handling the outer diameter, a circuit board with semiconductor elements mounted thereon is obtained.

[Brief explanation of the drawing]

FIG. 2(n) is an enlarged sectional view showing the structure of the same. 11... Insulating board for inner layer 12... Storage hole 1
4... Circuit 15... Insulating substrate for bottom plate 17... Insulating substrate for surface layer 21... Hole for making copper foil lead wire 22... Copper foil lead wire

Claims (1)

[Claims] After drilling a semiconductor element housing hole, a hole for creating a copper foil lead wire, and a reference hole in the specified position of a synthetic resin electrical insulating board or synthetic resin tape coated with adhesive on one side, place the copper foil on the adhesive coated side. After thermal compression bonding, etching resist ink was filled in the hole for creating the copper foil lead wire, and a conductor circuit and the copper foil lead wire were formed by etching.On one side of the inner layer board, a hole larger than the semiconductor element storage hole and the copper foil were formed. Drill a hole for making lead wires and a reference hole, and then make a semi-conductor.
A semiconductor characterized in that an insulating substrate for a surface layer having a frame for preventing resin leakage for sealing a component element is bonded to an insulating substrate for a bottom plate having a hole for making a copper foil lead wire and a reference hole on the other side. Composite printed wiring board for device mounting.