JPH04132293A - Polyimide resin multilayer wiring board - Google Patents

Abstract

PURPOSE:To realize a high speed propagating speed without weakening a close contact by composing an insulting layer between a signal layer and a ground layer of polyimide resin having low permittivity. CONSTITUTION:A power source layer 3 and a normal insulating layer 5 having a viahole 4 of polyimide resin are formed on a board l. A GND interconnection layer 6 is formed thereon. An insulating layer 7 having the viahole 4 is formed of the polyimide having low permittivity thereon. A signal interconnection layer 8 and the normal insulating layer 5 are formed thereon. Thereafter, an interconnection layer 8, a low permittivity polyimide insulting layer 7, a GND layer 6, a normal polyimide resin insulating layer 5, a power source.signal transfer layer 9, a normal polyimide resin insulating layer 5, and an electric component placing layer 10 are sequentially formed in this order. Since the layer 7 has lower permittivity by about 2.7 to 3.0 than that of the insulating layer composed of general polyimide resin insulating film to increase its signal propagating speed and the layers 7, 5 are alternately deposited, deterioration of close contact in the case of using only the low permittivity polyimide can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyimide resin multilayer wiring board used in electronic equipment.

[Conventional technology]

Conventionally, polyimide resin multilayer wiring boards are made by alternately laminating conductor wiring layers and polyimide resin insulating layers on a ceramic multilayer wiring board, and the polyimide resin insulating layers generally have a dielectric constant of about 3.4. It was constructed using a polyimide resin of 3.8 to 3.8.

That is, as shown in FIG. 2, on a ceramic or glass ceramic multilayer wiring board 21, a conductor wiring 22 forms a power supply layer 23, an insulating layer 25 having a via hole 24, and a ground (hereinafter referred to as GND). Wiring layer 2
6. The insulating layer 25, the signal wiring layer 28, and the insulating layer 25 are laminated in order, and finally the power supply/signal transfer layer 29 and the insulating layer 25
, an electrical component mounting layer 30 was formed to constitute a multilayer wiring board.

[Problem to be solved by the invention]

The conventional polyimide resin multilayer wiring board described above has conductor wiring layers and polyimide resin insulating layers alternately laminated on a ceramic multilayer wiring board. Kasei's PIQ, DuPont's PYRALYN, Toshi's Semicofine, etc. For photosensitivity, Hitachi Chemical's PL-1200, DuPont's PI-2702
D. It was composed of an insulating layer using Toshin's Photoneese, Asahi Kasei's PIMEL, etc.

The dielectric constant, which affects the propagation speed of signals in wiring, is about 3.4 to 3.8 in general polyimide resin, which is said to be a good material for electronic materials. In order to achieve higher propagation speeds, polyimide with an even lower dielectric constant must be used.

Currently, the above-mentioned companies are producing polyimides having a dielectric constant of about 2.7 to 3.0. However, when wiring in multiple layers using this low dielectric constant material, there is a problem in that the adhesion between polyimide and polyimide is weak. This is because the reactivity is weak due to F (fluorine) added to the polymer, and because the polymer structure is a rigid rod-like structure, the adhesion between polyimide and polyimide becomes weak when multilayered using only this material. Therefore, it is not suitable as the insulating material F4 of a multilayer wiring board.

[Means to solve the problem]

The present invention is a polyimide resin multilayer wiring board formed by alternately laminating conductor wiring layers and insulating layers of polyimide resin, in which the insulating layer between the signal layer and the ground layer is made of a polyimide resin with a low dielectric constant.

Further, in the polyimide resin multilayer wiring board of the present invention, insulating layers made of the polyimide resin having a low dielectric constant and insulating layers made of a polyimide resin having a normal dielectric constant are alternately laminated.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

In FIG. 1, a power supply layer 3 is formed on a ceramic or glass-ceramic multilayer wiring board 1 by a conductor wiring 2 made of copper or gold, etc., with a thickness of 5 to 10 microns and a line width of 15 to 30 microns, using a plating method or the like. , an ordinary insulating layer 5 having polyimide resin via holes 4 on this substrate.
(If it is non-photosensitive, Hitachi Chemical's PIQ, DuPont's PY
RALYN, Toshin's Semico Fine, etc. For photosensitive materials, Hitachi Chemical's PL-1200, Dupont's P4-2702D
, Tore's Photonice, Asahi Kasei's PIMEL, etc.) 15
It is formed with a thickness of 1 to 25 microns. Then, the GND wiring layer 6 is formed thereon by plating or the like in the same manner as described above. And on top of this, low dielectric constant polyimide (for non-photosensitive, Hitachi Chemical's PIQ-900, PIQ-1800X-5
, DuPont PI-2566, PI-2610D, PI
-2611D, Asahi Kasei's TLSA (A), etc., if photosensitive, use Asahi Kasei's TL (E), etc.), and use Viahole 4.
An insulating layer 7 having a thickness of 15 to 25 microns is formed. On top of this, a signal wiring layer 8 is formed by plating or the like in the same manner as described above, and a normal insulating layer 5 having via holes 4 made of polyimide resin (if non-photosensitive, Hitachi Chemical's PIQ, DuPont's PYRALYN, Toshin's Semiconductor) If the film is photosensitive, a fine film (such as Hitachi Chemical's PL-1200, DuPont's PI-2702D, Toshi's Photonice, Asahi Kasei's PIMEL, etc.) is formed to a thickness of 15 to 25 microns. After that, in the above process, a signal wiring layer 8, a low dielectric constant polyimide insulating layer 7, a GND layer 6, a normal polyimide resin insulating layer 5, a power/signal transfer layer 9,
A normal polyimide resin insulating layer 5 and an electrical component mounting layer 10 are further formed in this order to obtain a multilayer wiring board.

With the structure of this embodiment, the low dielectric constant polyimide insulating layer 7
Since the normal polyimide insulating layers 5 and 5 are alternately laminated, the problem of poor adhesion between polyimides when only low dielectric constant polyimide is used is improved. Moreover, since the signal wiring delay is caused by the dielectric constant of the insulating layer between the ground layer and the ground layer, by using a low dielectric constant material in this part, the electrical characteristics of the wiring board can also be improved.

〔Effect of the invention〕

As explained above, according to the present invention, in a polyimide resin multilayer wiring board in which conductive wiring layers and organic resin insulating layers are alternately laminated, the insulating layer between the signal layer and the GND layer is made of a low dielectric constant polyimide resin. This results in a dielectric constant of 2.7 to 3 compared to an insulating layer made of a general polyimide resin insulation film, which has a dielectric constant of about 3.4 to 3.8.
．． By lowering it to about 0, the signal propagation speed can be increased. Also, low dielectric constant polyimide is used as a signal layer and GND.
By using this material only between layers, it is possible to solve the problem of this material, which is unsuitable as an insulating material for multilayer wiring boards because the adhesion between polyimide and polyimide is weak when wiring is attempted in multiple layers.

Line layer, 6.26... GND wiring layer, 7... Insulating layer using low dielectric constant polyimide, 8. ．． 28... Signal wiring layer, 9, 29... Power supply/signal replacement layer, 1o, 3
0: Electrical component mounting layer.

Claims (2)

[Claims] 1. A polyimide resin multilayer wiring board formed by alternately laminating conductor wiring layers and insulating layers of polyimide resin, characterized in that the insulating layer between the signal layer and the ground layer is composed of a polyimide resin with a low dielectric constant. Multilayer wiring board. 2. 2. The polyimide resin multilayer wiring board according to claim 1, wherein the insulating layers made of polyimide resin having a low dielectric constant and the insulating layers made of polyimide resin having a normal dielectric constant are alternately laminated.