JPH02119298A - Manufacture of multilayer printed wiring board for mounting semiconductor element - Google Patents

Abstract

PURPOSE:To form a recessed groove having a flat bottom in contact with an inner layer copper foil surface without damaging the inner layer copper foil by forming a resist film in advance at a section of a bottom of a recessed groove. CONSTITUTION:A photosensitive resist film is laminated on a surface of an insulating board 1 and a resist film 4 is formed at a recessed groove formation section on a circuit pattern 3 through exposure and development. Then, a plurality of prepregs 5 and a copper foil 6 whose one side is roughened are provided to both sides of the insulating plate 1, and heated and fixed by pressure to form a lamination board 7. Then, an opening is drilled at a specified position of the lamination board 7, a through-hole 8 is formed, and a recessed groove 9 which attains a resist coat 4 from a surface of the lamination board 7 is formed by using a drill bit. After residue of the resist coat 4 is swelled and removed, or, smear 10 and resist residue 11 are oxidized and removed by plasma consisting of a mixture gas of oxygen and fluorine, then, copper plate 12 is applied all over including an inner wall of a through-hole 8 and an inner wall of the recessed groove 9 of the lamination board 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a multilayer printed wiring board for mounting a semiconductor element, and in particular, a method for manufacturing a multilayer printed wiring board for mounting a semiconductor element, which includes a step of forming a recess for directly mounting a semiconductor element. The present invention relates to a method for manufacturing a printed wiring board.

[Conventional technology]

BACKGROUND ART Conventionally, as a printed wiring board for directly mounting a semiconductor element, it has been proposed to provide a recessed portion for mounting a semiconductor element on the surface of the printed wiring board, and the following manufacturing methods are available.

Printing and etching the copper foil of an insulating plate having copper foil on both sides to form a circuit pattern, placing a plurality of prepregs on both sides of the insulating plate and an insulating plate or copper foil having copper foil on one side, and heating. A laminated plate is formed by pressure bonding, and after forming through holes and concave grooves in the laminated plate using a drill bit, panel plating is applied to the entire surface, conductors on the surface are printed and etched, and through holes and concave grooves for mounting semiconductor elements are formed. A conductive circuit including grooves is formed to create a multilayer printed wiring board for mounting semiconductor elements. There are two methods of making the bottom of the concave groove an insulating plate or an inner ground layer.

[Problem to be solved by the invention]

In the conventional manufacturing method described above, the adhesion of the plating at the bottom of the concave groove is poor, especially when the bottom of the concave groove for mounting the semiconductor element is an insulating plate, and the heating process during soldering or the manufacturing process is difficult. However, there was a drawback in that the plating on the bottom of the concave groove peeled off from the insulating plate.

In addition, if the bottom of the concave groove is the internal copper foil surface, the router
Because the positional accuracy of the bit in the depth direction is poor compared to the thickness of the inner layer copper foil, and the unevenness at the bottom of the concave groove is larger than the thickness of the inner layer copper foil, it is possible to accurately form the concave without destroying the inner layer copper foil. There was a drawback in that it was difficult to process the groove so that the top surface of the inner layer copper foil was at the bottom.

An object of the present invention is to provide a semiconductor element mounting device that prevents the plating in the concave groove from peeling off from the insulating plate and allows the concave groove to be precisely processed so that the top surface of the inner layer copper foil becomes the bottom without destroying the inner layer copper foil. An object of the present invention is to provide a multilayer printed wiring board.

[Means to solve the problem]

The method for manufacturing a multilayer printed wiring board for mounting semiconductor elements according to the present invention includes the following steps: (a) printing and etching the copper foil of an insulating plate having copper foil on both the front and back surfaces to form a circuit pattern.

(b) forming a resist film on the semiconductor element mounting portion of the circuit pattern;

(c) A step of arranging either one of a plurality of prepregs and an insulating plate having a copper foil on one side and a copper foil on both the front and back surfaces of the insulating plate, and bonding them under heat and pressure to form a laminate.

(d) A step of providing through holes in the laminate.

(e) forming a concave groove reaching from the surface of the laminate to the resist film;

(f) At the same time as removing the smear from the through hole, the resist film remaining at the bottom of the concave groove is removed to expose the circuit pattern.

(g) After applying copper plating to the entire surface of the laminate, a conductor on the surface is printed and etched to form a conductive circuit including through holes and concave grooves for mounting semiconductor elements.

It is composed of:

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(g) are sectional views of main parts shown in the order of steps for explaining the first embodiment of the present invention.

In the first embodiment, first, as shown in FIG. 1(a), an insulating plate 2 having copper foil 1 bonded under heat and pressure on both the front and back surfaces is prepared. As the copper foil 1, a rolled copper foil having a thickness of 35 μm and roughened on one side was used, and as the insulating plate 2, an epoxy resin reinforced with glass fiber was used.

Next, as shown in FIG. 2(b), the copper foil 1 is etched on both the front and back sides of the insulating plate 2 by using a normal printing-etching method to etch the portions of the copper foil 1 where there is no connection between the inner layer circuit of the through-hole forming part and the through-hole. It was removed to form a circuit pattern 3.

Next, as shown in FIG. 1(c), a photosensitive resist film is laminated on the surface of the insulating plate 1, exposed to light, and developed to form a resist film rIA4 in the concave groove forming portion on the circuit pattern 3. was formed. Note that the developer contains 1.1.
1-trichloroethane was used.

Next, as shown in FIG. 1(d), a plurality of prepregs 5 and a copper foil 6 with one side roughened were placed on both sides of the insulating plate 1 and bonded under heat and pressure to form a laminate 7.

Next, as shown in FIG. 1(e), holes are drilled at predetermined positions in the laminate 7 to form through holes 8, and further,
A concave groove 9 reaching from the surface of the laminate 7 to the resist film 4 was formed using a drill bit.

Next, as shown in FIG. 1(f), the laminate 7 is spray immersed in methylene chloride to swell and remove the remaining resist film 4 at the bottom of the concave groove 9, or a mixture of oxygen and fluorine is added. Treated with plasma consisting of gas for 20 minutes, smear 1
After oxidizing and removing the resist residue 11, the entire surface of the laminated board 7, including the inner walls of the through holes 8 and the inner walls of the concave grooves 9, is subjected to conventional degreasing, catalyst treatment, electroless copper plating, and electrolytic copper plating. Do not form plating 12.

Next, as shown in FIG. 1(g), a circuit is formed on the laminate 7 by a normal printing-etching method, and the through holes 13. A semiconductor element mounting portion 14 and a conductive circuit 15 were formed to obtain a multilayer printed wiring board 20 for mounting semiconductor elements.

The thus obtained multilayer printed wiring board for mounting semiconductor elements had particularly good adhesion of the copper plating at the bottom of the concave groove for mounting semiconductor elements, and did not bulge during heat treatment such as soldering. . Furthermore, it was possible to create a concave groove with a flat bottom shape without damaging the inner layer copper foil during drilling bit processing.

In the second embodiment, an alkali-soluble photosensitive resist film was used to form the resist film 4 of the first embodiment shown in FIGS. A multilayer printed wiring board for mounting semiconductor elements was prepared in exactly the same manner as in the first example except for the following steps.

Similarly to the first embodiment, the thus obtained multilayer printed wiring board for mounting semiconductor elements has good adhesion of the plating at the bottom of the concave groove, and does not bulge during heat treatment such as soldering. Furthermore, it was possible to create a concave groove with a flat bottom shape without damaging the inner copper foil.

〔Effect of the invention〕

As explained above, the present invention involves forming a resist film in advance on the bottom portion of the concave groove when forming the concave groove in the semiconductor element mounting portion of a multilayer printed wiring board for mounting semiconductor elements. This makes it possible to form a concave groove with a flat bottom in contact with the inner copper foil surface without damaging the inner copper foil, significantly improving the moisture absorption characteristics, electromagnetic shielding characteristics, heat dissipation characteristics, etc. of the mounted semiconductor element. There is an effect that can be done.

Furthermore, by using plasma treatment to remove smear caused by drill and drill bit processing, and at the same time removing residual odor from the resist film, an economical manufacturing method can be obtained.

...Laminated plate, 8...Through hole, 9...Concave groove, 1
o river smear, 11... Resist residual fragrance, 12... Copper plating, 13... Through hole, 14... Semiconductor element mounting part, 15... Conductive circuit, 20... Multilayer for semiconductor element mounting Printed wiring board.

Agent Patent Attorney Susumu Uchihara

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a) to 1(g) are sectional views of main parts shown in order of steps for explaining the manufacturing method of the first embodiment of the present invention.

Claims (1)

[Scope of Claims] A method for manufacturing a multilayer printed wiring board for mounting semiconductor elements, comprising the following steps (a) to (g). (a) A step of printing and etching the copper foil of an insulating plate having copper foil on both the front and back surfaces to form a circuit pattern. (b) forming a resist film on the semiconductor element mounting portion of the circuit pattern; (c) A step of arranging either one of a plurality of prepregs and an insulating plate having a copper foil on one side and a copper foil on both the front and back surfaces of the insulating plate, and bonding them under heat and pressure to form a laminate. (d) A step of providing through holes in the laminate. (e) forming a concave groove reaching from the surface of the laminate to the resist film; (f) At the same time as removing the smear from the through hole, the resist film remaining at the bottom of the concave groove is removed to expose the circuit pattern. (g) After applying copper plating to the entire surface of the laminate, a conductor on the surface is printed and etched to form a conductive circuit including through holes and concave grooves for mounting semiconductor elements.