JP2002111176A - Method of forming conduction path and substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a conduction path on an insulating substrate efficiently without employing etching, which requires wastewater treatment equipment. SOLUTION: A mask member 2 having an opening 21 in a conduction path pattern is allowed to adhere to a surface of an insulating substrate 1. After a conductive layer 3 is formed in the opening 21 by vapor deposition or sputtering, the mask member 2 is removed from the insulating substrate 1 to form a conduction path 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for forming a conductive path, and more particularly to a method for forming a conductive path without using etching.

[0002]

2. Description of the Related Art Most of substrates on which conductive paths are formed on the surface are generally manufactured as follows. FIG. 2 shows a schematic process diagram of the production. Copper foil 101 on the surface of the insulating substrate 1
(FIG. 2A), a photoresist 104 is applied to the surface of the copper foil 101, and exposure and development are performed to cover the conductive path pattern portion with the photoresist 104 (FIG. 2B). Then, the copper foil 101 other than the conductive path pattern is removed by etching (FIG. 3C). Further, by removing the photoresist 104, the conductive path pattern is transferred to the copper foil 101 (FIG. 4D). Next, nickel 102 and gold 103 are laminated on the copper foil 101 by electrolytic plating or electroless plating to complete the conductive path 4 (FIG. 3E).

[0003]

In such a method for forming a conductive path, in order to remove the copper foil 101 other than the conductive path pattern, an aqueous solution of ferric chloride and cupric chloride is generally used as an etching solution. Used. Since wastewater treatment equipment is indispensable for recycling or discarding this etching solution, manufacturing equipment has been increased in size. In addition, this has hindered simplification of the manufacturing process.

[0004] The present invention has been made in view of such conventional problems, and has as its object to provide a method for efficiently forming a conductive path without using etching which requires wastewater treatment equipment. It is assumed that. Another object of the present invention is to provide a substrate on which a conductive path is formed without using etching.

[0005]

In order to achieve the above object, in the method of forming a conductive path according to the present invention, a mask member having an opening in the form of a conductive path pattern is attached to the surface of an insulating substrate, and the vacuum deposition is performed. Alternatively, after forming a conductive layer in the opening by sputtering, the mask member is removed from the insulating substrate to form a conductive path.

In the substrate of the present invention, the conductive path formed by the above-described forming method is provided on the surface of the insulating substrate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies as to whether or not conductive paths can be efficiently formed on an insulating substrate without using etching which requires wastewater treatment equipment. There has been no attempt at all with the seemingly simple idea that instead of shaping the conductive layer covering the entire surface of the surface of the conductive substrate to form a conductive path, the conductive layer only needs to be formed on the conductive path forming portion of the insulating substrate surface. The present invention has been accomplished based on the idea which has not been achieved.

That is, a major feature of the forming method of the present invention is that a mask member having an opening in the form of a conductive path pattern is applied to the surface of an insulating substrate, and a conductive layer is formed in the opening by vacuum evaporation or sputtering. Is to do.

Hereinafter, the forming method of the present invention will be described with reference to the schematic process chart of FIG. Of course, the forming method of the present invention is not limited to this. First, a mask member 2 having an opening 21 in a conductive path pattern shape is attached to the surface of an insulating substrate 1 (FIG. 1A). The insulating substrate 1 used here is not particularly limited as long as it has an insulating property, and a conventionally known one can be used. For example, an epoxy glass material, a polyimide amide material, a ceramic material such as alumina, or the like can be suitably used.

The mask member 2 to be used is not particularly limited as long as it can withstand vacuum deposition or sputtering. For example, a glass material, a ceramic material such as alumina,
Photoresist is exemplified. A conventionally known method can be used to form the opening 21 having the conductive path pattern shape in the mask member 1. When a glass material or a ceramic material is used as the mask member, the conductive path pattern portion is scraped off using, for example, a router. The opening may be formed by pressing.
When a photoresist is used as a mask member, the conductive path pattern may be exposed and developed to form an opening having a conductive path pattern shape. The thickness of the mask member needs to be equal to or greater than the thickness of the conductive layer. If the thickness is 0.5 mm or more, there is no practical problem.

The means for attaching the mask member 2 to the surface of the insulating substrate 1 is not particularly limited. For example, the mask member 2 may be attached with an adhesive, or may be attached with the periphery fixed with a fixing jig. Is also good. Considering that the mask member 2 must be removed from the insulating substrate at the final stage, it is desirable to apply the mask member 2 with an easily removable fixing jig.

Next, the conductive layer 3 is formed in the opening 21 of the mask member 2 by vacuum evaporation or sputtering (FIG. 2B). Since a conductive material is deposited and deposited on the surface of the insulating substrate 1 exposed from the opening 21 of the mask member 2 by vacuum evaporation or sputtering, the conductive layer 3 having a uniform thickness and composition and having a high precision is formed. It is formed. The material forming the conductive layer 3 is copper, nickel,
Metal materials such as gold, silver, titanium, molybdenum, zinc, and iron are suitable. Since a semiconductor element is soldered or a gold wire is bonded on the conductive layer 3, a material having excellent soldering characteristics and bonding properties is desirable as the material of the conductive layer. Is particularly preferably gold or silver among the above materials. Therefore, the conductive layer may have a single-layer structure of gold or silver. However, since the conductive layer requires a certain thickness, the use of gold or silver significantly increases the manufacturing cost. Further, depending on the type of the insulating substrate, gold or silver may not be able to secure sufficient adhesion to the substrate. Therefore, it is recommended to stack the conductive layers and separate the functions. For example, gold or silver having excellent soldering characteristics and bonding properties is used for the outermost layer, and copper having excellent adhesion to the insulating substrate is used for the lowermost layer. These two
Although a layer structure may be used, copper may be dissolved in the molten solder during soldering and the conductive path pattern may be destroyed.Therefore, it is difficult to form an intermetallic compound and a nickel layer that does not melt and dissolve in the molten solder is formed of gold. It is preferable to form between the layer or the silver layer and the copper layer to prevent diffusion of gold and silver into the copper layer. FIG.
(B) shows such a layer structure, that is, the conductive layer 3 having a three-layer structure of the copper layer 31, the nickel layer 32, and the gold layer 33. When the conductive layers 3 are stacked, each layer may be formed by any of vacuum evaporation and sputtering.

In the case of a conductive layer having the layer structure shown in FIG. 1B, a copper layer: 10 to 20 μm, a nickel layer: 1 to 20 μm.
The range is preferably 10 μm, and the gold layer is preferably in the range of 0.1 to 0.5 μm. The control of the layer thickness can be performed by the processing time of vacuum evaporation and sputtering. For the above layer thickness,
The processing time is generally about several minutes to 30 minutes.

In the present invention, vacuum deposition, which is one means for forming a conductive layer, is a method in which a deposition material is heated in a vacuum and the generated vapor is condensed and adhered on a substrate to form a thin layer. If the degree of vacuum is low, the residual gas or a reaction product with the residual gas is mixed into the layer to be formed, and furthermore, the vaporized molecules are prevented from reaching the substrate, so that the layer forming speed is reduced. Therefore, the degree of vacuum is preferably set to 10 ⁻² Pa or less.

Examples of the method of heating the vapor deposition material for forming the conductive layer include resistance heating, external heating crucible, electron beam, high frequency, laser, and the like. Beam heating is preferred.

The layer forming speed in vacuum evaporation is proportional to the evaporation speed, and decreases in proportion to the square of the distance between the evaporation material and the substrate. Therefore, in order to form a layer quickly, the distance between the deposition material and the substrate should be as short as possible.

[0017] Sputtering, another means of forming a conductive layer, causes particles having high energy to collide with a solid material and deposits atoms and molecules struck out of the solid material on a substrate to form a thin layer. It is a method of forming. Specifically, once the inside of the vacuum chamber is evacuated to a high vacuum, 10 ^-1
Glow discharge is caused by introducing argon of 10 ² Pa and applying a high DC voltage (1 to 5 kV) between the electrodes. The positive ions of argon generated as a result of the glow discharge are accelerated toward the target (cathode) by the electric field, collide with the target surface, and strike the target material. The ejected atoms and atomic groups accumulate on the substrate to form a thin layer. As the target material, the above-described deposition material can be used here.

As the apparatus for performing sputtering, a conventionally known apparatus can be used. For example, a DC sputtering apparatus,
Magnetron sputtering device, facing target type sputtering device, ion beam sputtering device,
An ECR sputtering device may be used.

In FIG. 1C, when the conductive layer 3 is formed in the opening 21, the mask member 2 is removed from the insulating substrate 1. Although there is no particular limitation on the removing means, removal by a dry process is desirable from the viewpoint of simplification of the manufacturing process. More preferably, when the mask member 2 is adhered as described above, the mask member 2 is peeled off and fixed. When fixed with a jig, release the fixing jig to release the mask member 2
Should be removed. Thereby, the conductive path 4 is formed on the insulating substrate 1. It is desirable to reuse the mask member 2 removed from the viewpoint of manufacturing efficiency and effective use of resources.

The substrate having the conductive path 4 formed on the surface of the insulating substrate 1 in this manner can be used as, for example, a printed circuit board or a semiconductor chip substrate.

[0021]

According to the method of forming a conductive path of the present invention, a mask member having a conductive path pattern-shaped opening is applied to the surface of an insulating substrate, and a conductive layer is formed in the opening by vacuum evaporation or sputtering. After that, the mask member is removed from the insulating substrate to form a conductive path, so that the conductive path can be efficiently formed on the insulating substrate without using the etching required for wastewater treatment equipment, and the size of the manufacturing equipment can be reduced. And simplification. Further, since the substrate of the present invention has the conductive path formed on the insulating substrate without using the etching, the substrate can be efficiently manufactured with the downsized and simplified manufacturing equipment.

[Brief description of the drawings]

FIG. 1 is a process chart showing one embodiment of a method for forming a conductive path according to the present invention.

FIG. 2 is a process chart showing a conventional method for forming a conductive path.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Mask member 3 Conductive layer 4 Conductive path 31 Copper layer 32,102 Nickel layer 33,103 Gold layer 101 Copper foil 104 Photoresist

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01L 21/88 TF term (Reference) 4K029 AA07 AA09 AA11 BA04 BA05 BA08 BA12 BB02 BC03 BD01 CA01 CA05 DB21 DC34 HA01 HA02 5E343 AA15 AA17 AA18 AA24 BB17 BB22 BB23 BB24 BB25 BB35 BB39 BB43 BB44 BB54 DD23 DD25 ER18 GG11 5F033 HH07 HH11 HH13 HH14 HH16 HH18 HH20 MM08 PP15 PP19 QQ42 QQ43 VV07

Claims (2)

[Claims] 1. A method for forming a conductive path on a surface of an insulating substrate, comprising: applying a mask member having an opening in the form of a conductive path on the surface of the insulating substrate; Forming a conductive layer on the portion, removing the mask member from the insulating substrate, and forming a conductive path. 2. A substrate having a conductive path formed by the method according to claim 1 on a surface of an insulating substrate.