JPH0810792B2 - Method for manufacturing multilayer wiring board - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a multilayer wiring board having a hybrid structure including a thick film wiring board portion and a thin film wiring board portion. As a multi-layer wiring board for a large-capacity hybrid integrated circuit used in an electronic computer or the like, a wiring is generally formed by a thick film printing sintering method, and a board using alumina ceramics as a board and an interlayer insulator. Is used. However, in recent years, there has been a strong demand for high functionality and high speed in electronic computers,
As a result, a hybrid integrated circuit substrate having a large wiring capacity has been required. In the thick film alumina ceramic substrate, the wiring density is limited by the accuracy of the printing process (minimum possible wiring pitch 150 μm), so that the wiring layers 5 to 10 and the insulating layers 5-1
A substrate having a substrate size of 100 mm 2 has appeared with 0 layers. Since the increase in the number of layers significantly increases the number of connection points between layers,
There is a drawback that the yield of substrate manufacturing is significantly reduced.
In addition, an increase in the size of the board causes an increase in the number of signal transmission paths, and thus the speed cannot be increased. Therefore, it has been attempted to use a thin film photoprocess, which is a process in the semiconductor industry, for forming wiring. It is generally difficult to take out hundreds of terminals which can withstand attachment / detachment of a connector, which is required as a hybrid integrated circuit board for electronic computers, in a board which is multilayered using a thin film process. For this terminal, a conventional thick film multilayer wiring board in which pin connection parts made of sintered tungsten and plated with Ni are arranged all over the back surface of the substrate, and lead pins are connected to the connection parts with silver solder or solder solder is suitable. The circuit area that requires high density and high speed is the logic signal circuit. The power circuit ground layer has a sufficient margin in the wiring density of the conventional thick film multilayer wiring. Therefore, the logic signal layer is formed as a thin film substrate portion, and the power supply ground layer and the lead pin terminal portion are formed as thick film substrate portions.
A high speed substrate can be achieved. The thin-film / thick-film hybrid type multilayer wiring board can be manufactured by the process shown in FIG. The thick film substrate portion 10 including the power source / ground layer 2 and the lead pin terminal portion 3 made of sintered tungsten is formed by a green sheet method which is a usual method for producing a thick film multilayer substrate. The wiring terminals 4 of the thick film substrate portion connected to the wiring of the thin film substrate portion are formed by filling the through holes of the alumina insulating layer 5. A matching layer 6 to be the wiring of the thin film substrate is formed on the upper surface of the thick film substrate 10 by Al or Cr / Cu / Cr by resistance heating vapor deposition or sputtering which is a normal thin film process, and a negative resist is used. The matching layer 6 is patterned by so-etching. At this time, the wiring terminal 4 and the matching layer 6 are always overlapped. The thick film substrate portion 10 has variations in sintering shrinkage during manufacturing, and the positional variation of the wiring terminals 4 is 0.6 to 1.0% of the distance from the center of the position when viewed from the substrate center. For this reason,
In order to connect the two board portions over the entire area of the board, the width of positional variation must be given to the connection portion of the wiring terminal 4 or the matching layer 6. Therefore, the matching layer 6 must have the same wiring density as that of the thick film wiring board portion while using a photolithographic etching process capable of achieving high density wiring. An SiO ₂ or polyimide film formed by a normal thin film process is used as an insulating layer 7, and a through hole 8 is formed by photolithography etching. After that, the wiring 61 of the thin film substrate is formed on the upper surface of the insulating layer 7 in the same manner as the matching layer 6, and the insulating layer 71 and the through hole 81 are formed in the same manner as the insulating layer 7 and the through hole 8. By repeating these steps, the thin film substrate 1
1 to form a multi-layer wiring board for high density and high speed. In this multilayer wiring board, the matching layer 6 is a layer for adapting thick film-thin film connection which does not contribute to high density.
In addition, the insulating layer 7 and two layers are required, which makes the process redundant and reduces the yield. A matching layer 6 is formed on the wiring terminal 4 in FIG.
There will always be places that are not covered by. This causes the etching liquid for metal etching at the time of patterning the matching layer 6 to come into contact with the wiring terminals 4, so that the wiring terminals 4 are oxidized (corroded) and the reliability is lowered. Further, since the surface roughness of the thick film substrate portion 10 is usually 3 to 4 μm, it is known that photolithography etching of the matching layer 6 is difficult and the stability of the wiring resistance is poor. An object of the present invention is to provide a method for manufacturing a multilayer wiring board having a hybrid structure composed of a thick film wiring board section and a thin film wiring board section, excluding the above manufacturing defects. [0008] The above-mentioned object is to make the through hole of the thick film wiring board portion a size that allows for the amount of positional displacement due to sintering shrinkage, and form a wiring terminal in the through hole.
An insulating layer is directly formed on the upper surface of the thick film wiring board portion without a matching layer, a through hole is formed in a part of the insulating layer by a photolithography etching method, and the wiring is formed through the through hole. This is accomplished by a method of manufacturing a multilayer wiring board having a hybrid structure including a thick film wiring board section and a thin film wiring board section, characterized in that terminals are connected to the thin film wiring board section. The present invention has a function of adapting the thick film wiring board portion and the thin film wiring board portion even if the thick film wiring board portion is misaligned due to the sintering shrinkage of the thick film wiring board portion, which was carried by the matching layer of the prior art. The wiring terminals formed in the through holes of the thick film wiring board portion are to be carried. That is, the size of the through hole in the thick film wiring board portion is set to a size that allows for the amount of positional deviation due to the sintering shrinkage of the thick film wiring board portion. as a result,
According to the present invention, the matching layer for matching which is required in the prior art is not necessary, and the photolithographic etching solution for metal etching used as a thin film process when forming the matching layer touches the wiring terminals 4 of the thick film wiring board portion. However, the problem of reducing reliability due to oxidation (corrosion) is eliminated, and it is necessary to form a matching layer by performing photolitho etching, which is a thin film process, on the thick film wiring board with a rough surface. lost. The present invention will be described in detail with reference to the embodiment shown in FIG. FIG. 7A is a diagram for explaining a method of forming a thick film wiring board portion, and FIG. 7B is a diagram for explaining a method of forming a thin film wiring substrate portion on a thick film wiring substrate portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 10 shown in FIG. 2 is an alumina thick film multilayer wiring board portion 10 manufactured by a green sheet method, which includes a power supply wiring layer and a ground layer 2 made of a sintered body of tungsten. The wiring terminals 4 are formed by filling a through hole of the alumina insulating layer 5 with tungsten paste and sintering it.
The diameter of the wiring terminal 4 is a diameter obtained by adding dimensional variation to the through hole diameter of the thin film to be connected. The formula for the dimensional variation is (dimensional variation) = (variation in sintering shrinkage in the green sheet method) x (dimension of the long side of the substrate) x 1/2, where (variation in sintering shrinkage in the green sheet method) ) Is 0.6 to 1.0%, (long-side dimension of substrate) is 50 m
When m, (dimensional variation) = (0.6 to 1.0%) × (50 mm) × 1/2 = 0.15 to 0.25 mm. When the through hole diameter of the thin film is 50 μm, the diameter of the wiring terminal 4 is 200 to 300 μm.
The lead pins 9 connected to the sintered tungsten pads with silver solder are attached to the back surface of the substrate portion 10. Wiring terminal 4
Is the same plane as the upper surface of the alumina insulating layer 5 or 10 μ
It is formed so as to project below m. This board part 1
0 is coated with a polyimide resin by a spin coating method and heat-cured to form the insulating layer 7. The insulating layer 7 is coated with a negative resist (for example, OMR83 manufactured by Tokyo Ohka Kabushiki Kaisha), the resist is patterned by exposure to ultraviolet light, and a through hole 8 is formed in the insulating layer 7 above the wiring terminal 4 by wet etching. The etching liquid used here is for the insulating film, and the type of etching liquid is different from that for metal. Therefore, the etching liquid for the insulating film does not substantially affect the wiring terminals 4 made of metal.
The use of a negative resist for forming the through holes 8 is because the thick film substrate portion 10 is hard and has warps and undulations. , In order to avoid generation of pinholes in the insulating layer 7. And wiring terminal 4
The reason why the upper surface of (1) is not submerged from the upper surface of the alumina insulating layer is to prevent the through hole 8 from being unable to be formed due to the wraparound of the ultraviolet light if there is a gap from the mask during exposure because a negative resist is used. After forming the through hole 8,
Wiring 6 made of aluminum or titanium + copper + titanium by resistance heating or electron beam evaporation sputtering
1 and patterned by a conventional photolithographic process. Since the wiring 61 is patterned on the smooth insulating layer 7 rather than on the thick film multilayer wiring board portion 10 (surface roughness 4 to 6 μm) having a large surface roughness, a high pitch of 20 to 40 μm is required. The wiring can be densely formed, and the occurrence of pinholes can be suppressed. Further, as described above, the patterning of the wiring 61 is performed on the insulating layer 7, and the matching layer 6 is patterned on the wiring terminal 4 by using an etching solution for metal as in the prior art. By doing so, there is no concern that the wiring terminal 4 is also etched. After that, the polyimide resin layer 71 and the wiring 61 are repeatedly formed on the upper portion of the thin film multilayer wiring board portion 11. The lead pins 9 may be attached after the thin film wiring board portion 11 is formed. As described above, according to the present invention, the density can be increased by 2 to 3 times that of the conventional thick film multilayer wiring board. In addition, the total number of wires and the number of through-hole connections can be greatly reduced,
Product yield is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a conventional method for manufacturing a thin film hybrid multilayer substrate. FIG. 2 is a diagram illustrating an example of the present invention. [Explanation of reference numerals] 10 ... Thick film multilayer wiring board section, 11 ... Thin film multilayer wiring board section, 4 ... Wiring terminals of thick film board section, 5 ... Insulating layer of thick film board section, 7, 71 ... of thin film board section Insulating layer, 6 ... Matching layer, 61
... Wiring of thin film substrate, 9 ... Lead pin.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kamei Tsuneaki             Stock, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Company Hitachi, Ltd. Production Technology Laboratory              (56) References JP-A-56-42399 (JP, A)               Japanese Patent Laid-Open No. 50-28655 (JP, A)               JP-A-53-28266 (JP, A)

Claims (1)

[Claims] 1. The through holes in the thick film wiring board are
A wiring terminal is formed in the through hole with an amount of misalignment taken into consideration, and an insulating layer is directly formed on the upper surface of the thick film wiring substrate without a matching layer, and a part of the insulating layer is formed. A hybrid structure comprising a thick film wiring board portion and a thin film wiring board portion, characterized in that a through hole is formed by a photolithography etching method, and the wiring terminal and the thin film wiring board portion are connected through the through hole. Manufacturing method of multilayer wiring board.