JP2003347453A - Method of forming wiring within through-hole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily form conductive metal wiring without any fear of e.y. a chemical liquid within a through-hole having higher aspect ratio provided to a base material at a lower cost. <P>SOLUTION: A metal pole comprising fine particles of a conductive metal material is formed in the through-hole with a gas deposition method at the time of forming the conductive metal wiring into the through-hole. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a wiring in a through hole of a substrate having the through hole.

[0002]

2. Description of the Related Art First, a gas deposition method will be briefly described. The gas deposition method comprises an ultrafine particle generation chamber, a film forming chamber, a transfer pipe, and the like. This is a dry film forming method that draws a pattern directly by guiding the film to the film forming chamber through a transfer pipe by a pressure difference between the film forming chamber and the high-speed jet from a nozzle (The 11th Circuit Packaging Academic Concert, 17c
-12, Mr. Iwashige, etc.). The film formed by this gas deposition method is a film composed of ultrafine particles, and since the ultrafine particles have a smaller particle size than ordinary fine particles, the specific surface area is enormous. In the case of ultrafine particles formed by a gas deposition method, the particle size is primarily generated, and is usually several tens to several hundreds of angstroms.

[0003] The particle size contributes to the physical properties, chemical properties, electrical properties and the like of the film, and specifically, adhesion to the substrate, dielectric constant, surface roughness, refractive index, and the like. A number of properties are affected, such as conductivity, conductivity, and adsorption properties.

Next, an example of a method for forming a wiring in a contact hole will be described.

First, after the glass surface is degreased and washed, the surface is roughened by etching, and the glass surface is immersed in a tin / palladium colloid solution to capture the colloid particles on the rough surface.
Next, the tin protective film of the tin-palladium colloid is removed with an acid to form a palladium metal nucleus for plating.

After performing such a treatment, the substrate is immersed in an electroless nickel-phosphorus plating (hereinafter referred to as Ni-P) solution to form a Ni-P plating film using the palladium metal nucleus as a catalyst nucleus. A conductive metal film is formed.

[0007] As a known example, after glass is roughened with 10% hydrofluoric acid, a palladium nucleus is provided, and electroless Ni-P
A paper for forming plating has been published (Surface Technology Vo
l. 44, no. 10, 1993).

As described above, when a conductive metal film is formed in a contact hole by plating, the Ni-
After forming a P plating film of about 1 μm, a technique of laminating a low resistance layer of several μm to several tens μm such as Cu plating is used.

As another method, a semiconductor layer made of either ZnO or WO3 is formed on an insulating film, and Pd, Au, Ag, Pt, etc. are deposited thereon, and then Cu
And the like (Japanese Patent Application Laid-Open Nos. 6-61619 and 4-17211) are known.

Further, a method of forming a metal column for contact using a gas deposition method is disclosed in Japanese Patent Laid-Open No. 6-2162.
No. 58 is known.

[0011]

However, the method of forming a conductive metal wiring in a contact hole by the above-mentioned conventional method has a drawback that the number of steps is large. That is, a process of roughening the insulating layer, a process of dipping in a palladium / tin colloid solution, a process of removing the tin protective film, and the like are added to the actual film forming process. Along with that,
There is a problem that the cost increases.

[0012] In addition, restrictions such as resistance to chemical liquids and problems such as treatment of waste chemical liquids arise, and convenience is also imposed on ease of handling. Further, there is a problem that it becomes difficult to form a metal film as the hole diameter of the through hole is small and the aspect ratio is high.

On the other hand, in the case of contact wiring using metal pillars using a gas deposition method, after forming the metal pillars, an insulating material such as a polyimide solution is applied to form contacts above and below the polyimide layer, thereby forming a thick film. For example, there is a problem that it cannot be applied to a structure penetrating the silicon substrate itself.

(Object of the Invention) The present invention is to solve the above-mentioned problems, and it is easy to provide a low-cost, high-aspect-ratio through-hole formed in a substrate, and to disperse a chemical solution or the like. An object is to form a conductive metal wiring without concern.

[0015]

The present invention has the following means to solve the above-mentioned problems.

In the method of forming wiring in a through-hole according to the present invention, in a substrate having a through-hole, a metal column made of conductive metal fine particles is formed in the through-hole by a gas deposition method. Is performed while covering with a mask having an opening in the target portion.

Further, the mask formed on the substrate is a positive resist, and when exposing the resist, the substrate having a through hole is used as an exposure mask for the resist.

The method may further include a step of covering a back surface of the through hole on the deposition side. In addition, the method of forming a wiring in a through-hole according to the present invention is characterized in that a step of forming a metal pillar made of conductive metal fine particles in the through-hole and a wiring having a contact with the metal pillar are simultaneously formed. Is what you do.

[0019]

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partial cross-sectional view of a base having wiring formed in a through hole by a gas deposition method. Also,
FIG. 2 is a process flow chart showing a forming process in this embodiment. Hereinafter, the present embodiment will be described based on the process flow chart of FIG. The substrate used in this example was a silicon substrate having a thickness of 0.625 mm, and the diameter of the through-hole was 100 μm.

First, the formation of the through hole will be described. As shown in FIG. 2, a positive resist 4 (in this example, MCPR4200 manufactured by Shipley Co., Ltd.) was applied onto a silicon substrate 3 by a spin coater as shown in FIG.
(A)). After the resist 4 was dried, the resist at the desired through-hole position was removed by exposing and developing with g-line. After removing the resist, the silicon oxide film 5 having a thickness of 0.5 μm previously formed on the silicon substrate 3 was removed. In this embodiment, the silicon oxide film 5 was removed by reactive ion etching using CF4 as a main source gas. In a state where CF4 gas is introduced into a reaction vessel (not shown) in which the substrate is installed, and the pressure inside the reaction vessel is set to about 0.1 to several Pa,
Etching was performed for about 10 minutes by generating RF plasma to remove the silicon oxide film 5. The same processing was performed on the back surface of the substrate on which the above process was performed (FIG. 2B).

Next, through holes 7 were formed by anisotropic etching. In the present embodiment, the through-hole 7 was formed by exposing to TMAH 23% and 80 ° C. for about ten hours, and thermal oxidation was performed again to form the silicon oxide film 6 in the through-hole, thereby completing the through-hole 7 ( (FIG. 2 (c)).

Next, the through hole 7 completed in the previous process
The method of forming the wiring inside is described.

FIG. 3 shows a configuration diagram of the gas deposition apparatus used in this embodiment. In this embodiment, an arc method is used as the evaporation method. In FIG. 3, 15 is an ultrafine particle generation chamber,
Is a film formation chamber. Reference numeral 18 denotes an arc electrode, and reference numeral 20 denotes a wiring material. The substrate 10 is provided on a stage 13,
If necessary, the substrate 10 can be heated using the substrate heater 9.

The ultrafine particles are generated in the ultrafine particle generation chamber 15 by arc discharge. The pressure in the ultrafine particle generation chamber 15 is set to be in a range of about 10 kPa to 100 kPa.
It is adjusted by the introduction amount and the exhaust amount of the carrier gas 25. On the other hand, the pressure in the film formation chamber 16 is reduced by two to three digits from the pressure in the ultrafine particle generation chamber 15. Therefore, the ultrafine particles (not shown) generated in the ultrafine particle generation chamber 15 are sprayed on the substrate 10 via the transport pipe 12 and the nozzle 11 by a pressure difference between the two containers, thereby forming a film on the substrate 10. is there.

First, the substrate having the through-holes obtained in the previous process FIGS. 2A to 2C is set on the stage 13 in the film forming chamber 16. Next, the through hole of the silicon substrate and the nozzle 11 are positioned, and the film formation chamber 16 and the ultrafine particle generation chamber 15 are evacuated to 0.3 Pa or less by the pump 24.
Thereafter, a helium gas 25 was introduced into the production chamber 15. In this embodiment, the pressure in the production chamber was set to about 70 kPa.

Next, the transport tube 12 is moved in the horizontal direction in the figure so that the evaporated particles are not supplied into the transport tube until the discharge is stabilized, and the A is placed on a carbon hearth liner.
An arc discharge was generated for g20. In this embodiment, the discharge was performed at about 70 A and 19 V. After the discharge was stabilized, it was set at a position where the evaporated particles were supplied to the transport pipe 12 for about 3 seconds, and the transport pipe 12 was moved again to a position where the evaporated particles were not supplied, thereby forming a wiring into the through hole. (FIG. 2 (d)).

The resistance value of the Ag wiring obtained in this embodiment is about 1.5 times that of the bulk, and a value lower than the desired resistance value was obtained.

In this embodiment, the arc discharge method is used as a method for producing ultrafine particles in the gas deposition method.
For example, the present invention is not limited by an ultrafine particle generation method such as an induction heating method and a resistance heating method.

Although a silicon substrate is used in this embodiment for a substrate provided with a through hole, the same effect can be obtained in a substrate having a through hole, for example, a circuit board, and the type of substrate is limited. Not something.

In this embodiment, Ag is used as a wiring material. However, the material is not particularly limited as long as a material having a desired resistance can be obtained. In addition, deposition conditions are appropriately selected in accordance with the evaporation amount of the material.

(Embodiment 2) A second embodiment of the present invention will be described below with reference to FIG.

In this embodiment, a mask 35 having a through-hole position is formed on the spraying side 31 and a resist material 36 is formed on the back surface 32, and wiring is formed in the through-hole by a gas deposition method. .

First, through-holes were formed in the silicon substrate through the same steps as in Example 1 and FIGS. 2A to 2C (FIG. 4).
(A)).

Next, a positive type resist 35 (TMSR-TM, manufactured by Tokyo Ohka Kogyo Co., Ltd.)
V3) (FIG. 4B). After drying the resist material 35, the entire surface is irradiated with g-line from the back surface of the silicon substrate,
An opening 39 was formed by alkali development (FIG. 4).
(C)).

Further, the same positive type resist 36 (TMSR-V3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to the entire surface of the spray-side back surface 32 and dried (FIG. 4D).

After the resist 36 is dried, both surfaces are irradiated with g-rays, and a metal column 40 made of ultrafine Ag particles is formed in the through hole by the gas deposition method as in Example 1.
(E)), the resists 35 and 36 formed in the previous step were peeled off, and an Ag wiring was formed in the through hole (FIG. 4).
(F)).

The gas deposition conditions in this embodiment are the same as those in the first embodiment, and the gas deposition time in the through hole is shorter than that in the first embodiment, that is, about 2 sec.

Also, in the first embodiment, the A is positioned on the stage 13 of the gas deposition apparatus at the position of the through hole of the base.
g ultra-fine particles adhered, and a metal column composed of Ag ultra-fine particles adhered to the stage side. However, as described in this example, a protective film was formed on the back surface of the substrate on the gas deposition side. By doing so, it was possible to form metal wiring in the through-hole without adhesion of Ag fine particles to the stage and with efficient use of the material. Also, the resistance value of the Ag wiring was similar to that of Example 1, and was excellent.

(Example 3) In this example, metal pillars into the through-holes and wirings contacting them were formed simultaneously by the gas deposition method. The resist used in this example was the same as that used in Example 2.

FIG. 5 is a process perspective view of this embodiment. In the figure, 3 is a silicon substrate, and 5 is a silicon oxide film.

First, a through hole 7 is formed in the same manner as in the first embodiment.
A positive photoresist 41 was applied and dried. After the resist 41 was dried, the wiring pattern portion was exposed to g-line through a photomask having an opening in the wiring pattern portion, and the wiring pattern portion on one side was subjected to an alkali-soluble treatment (first alkali-soluble portion 47). Also, the same positive photoresist 42 was applied to the back surface on the side where the wiring pattern opening was formed, and dried (FIG. 5A).

Next, alkali development was performed to remove the resist material in the first alkali-soluble portion 47, and the wiring pattern portion was opened (FIG. 5B).

Then, the substrate obtained in the above step is placed on the stage 13 of the gas deposition apparatus shown in FIG. Then, ultrafine particles of Ag were deposited in the through-hole portions (FIG. 5C). The wiring section is formed by setting the stage feed speed to about 10
The wire was moved at 0 μm / sec, the feed of the through hole was stopped for about 2 seconds, and the stage was moved again at about 100 μm / sec to form a wiring.

Next, the positive resist 42 formed on the entire rear surface on the deposition side is exposed using a photomask having a predetermined pattern to form a second alkali-soluble portion 48, which is removed by alkali development (FIG. 9). 5 (d)).

After the development, the entire front and back surfaces of the substrate are irradiated with g-rays, and the substrate is again set on the stage in the gas deposition apparatus so that the removed surface (the surface on which the resist 42 is formed) in the previous process is on the nozzle side. Then, the wiring using Ag ultrafine particles was patterned 46 and alkali development was performed again to remove all the remaining resist pattern, thereby completing the wiring into the through-hole and the wiring 45 contacting it (FIG. 5).
(E)).

According to the present embodiment, the wiring on the substrate is formed simultaneously with the formation of the wiring in the through-hole, and the process can be shortened.

[0048]

As described above, when a conductive metal wiring is formed in a through-hole, a metal column made of conductive metal fine particles is formed in the through-hole by a gas deposition method, whereby, for example, plating is performed. The process becomes very simple as compared with the method. Further, the cost can be reduced due to the simplification of the process.

Further, the mask formed on the substrate is a positive resist, and when exposing the resist, the substrate having through holes is used as an exposure mask for the resist, so that an expensive photomask is not required, and The resist material in the through hole can be removed without alignment.

Further, the step of covering the back surface of the through-hole on the deposition side with a protective film can prevent the formation of metal columns on the stage through the through-hole during gas deposition. The metal pillar can be efficiently formed in the through hole.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of a method for forming a wiring in a through-hole according to the present invention.

FIG. 2 is a process flowchart of an embodiment of a method for forming a wiring in a through-hole according to the present invention.

FIG. 3 is a schematic view of a gas deposition apparatus as a means for forming wiring in a through-hole according to the present invention.

FIG. 4 is a process flowchart of a second embodiment of the present invention.

FIG. 5 is a process flowchart of a third embodiment of the present invention.

[Explanation of symbols]

2. Flow of ultrafine particles 3. Silicon substrate 4, 42 ... resist material 5, 6 ... silicon oxide film 7 ... Through-hole 8 ... metal pillar 10 ... substrate 11 ... Nozzle 12 ... Ultra fine particle transport tube 13 ... XY-Θ stage 15 ... Ultra-fine particle generation chamber 16 ... film formation chamber 18 ... Arc electrode 20 Wiring material 24 ... Pump 25 ... Helium gas cylinder 31 ... gas deposition side of substrate 32 ... Back side of gas deposition side of substrate 35, 36, 41 ... Positive resist 39 ... Opening 40 ... metal pillar 45, 46 ... wiring part 47: first alkali-soluble portion 48: Second alkali-soluble part

Claims (5)

[Claims] 1. A method for forming a wiring in a through-hole, wherein a metal column made of conductive metal fine particles is formed in the through-hole in a substrate having a through-hole by a gas deposition method. 2. The method according to claim 1, wherein the method is performed while covering the base with a mask having an opening at a target portion. 3. The method according to claim 1, wherein the mask formed on the base is a positive resist, and the base having a through hole is used as an exposure mask for the resist when exposing the resist. Method for forming wiring in through-hole. 4. The method for forming a wiring in a through hole according to claim 1, further comprising a step of covering a back surface on a deposition side of the through hole with a film. Internal wiring formation method. 5. The method according to claim 1, wherein a step of forming a metal pillar made of conductive metal fine particles in said through hole and a wiring having a contact with said metal pillar are simultaneously formed by a gas deposition method. Any of to 4
2. The method for forming a wiring in a through hole according to claim 1.