JP3366679B2 - Processing method of organic material - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for processing organic materials.

[0002]

2. Description of the Related Art First, in the processing of crystalline and amorphous inorganic materials, EEM: Elastic Emission Machinin is used as so-called ultra-precision processing for final surface finishing.
g (Japanese Patent Laid-Open No. 1-236939),
Very good technology has been developed. Also, in the pre-finishing stage of the final surface finishing, CVM: Chemical Vaporization using radical reaction is used as a processing method that does not cause residual cracks and defects such as thermally deteriorated layers and can perform highly accurate processing with high spatial resolution. Machining (Japanese Patent Laid-Open No. 4-
No. 128393) has been proposed.

On the other hand, since the organic material is relatively soft and easy to cut with a blade, conventionally, in many cases, there was no big problem in the processing even if a special processing method was not adopted.

[0004]

By the way, in recent years, many organic materials having high functionality (for example, high hardness, high heat resistance and low thermal deformation) have been developed, and along with this, there is a demand for processing accuracy of the organic materials. Is getting very severe. Therefore, recently, a processing method using a high-intensity laser beam has come to be used as a precision processing technology to meet such demands. According to this processing method, the processing surface is thermally treated. There are problems that an altered layer remains and that cost increases when processing a large area.

Further, as a method for processing such a highly functional organic material, there is currently no precise processing technique which is strain-free and does not cause a surface deterioration layer due to a thermal deterioration layer or ion bombardment.

Further, an organic material such as polyimide is rarely used alone, and is often used in a state of being laminated on a metal or a semiconductor, but the metal or the semiconductor is formed into a precise pattern by a photolithography technique or the like. While it is possible to process, organic materials do not have a precise processing method as described above, and this realizes precise composite materials (composite parts) composed of organic substances and metal substances. Is a major obstacle to

The present invention has been made in view of such circumstances, and can process an organic material precisely without distortion and does not generate a thermally deteriorated layer or a surface deteriorated layer due to ion bombardment on the processed surface. The intended purpose is to provide a method.

[0008]

According to the processing method of the present invention, an organic material W is separated from an electrode 2 by a predetermined gap in a reaction vessel 1 in which a processing electrode 2 having a predetermined shape is arranged. with placing, the container 1, a gas atmosphere and 1
/ 100 atm or more and 1 atm or less , high frequency power is applied to the machining electrode 2 to generate plasma between the electrode 2 and the organic material W, and radicals and organic material in the plasma are generated. It is characterized in that processing is performed by utilizing the reaction of (see FIG. 1).

[0009]

When plasma is generated between the electrode 2 and the organic material W which is the object to be processed by applying high frequency power to the processing electrode 2, radicals (free radicals) generated by the plasma discharge and organic material W are generated. By evaporation of the volatile compound generated by the reaction with, the organic material in the portion facing the processing electrode 2 is removed, and thereby the processing proceeds.

Here, since the mean free path of gas molecules is generally 10 ^-2 atm and several μm or less, the pressure of the atmosphere gas during processing should be set to, for example, 1/100 atmospheric pressure or more. Therefore, the charged particles are not accelerated at high speed by the electric field, and thus the processed surface of the organic material is not damaged by the sputtering due to the high-speed ion bombardment. Further, in the processing utilizing the radical reaction, physical stress does not act on the material in the processing process, and therefore, processing strain does not occur.

Here, He, N is used as an atmosphere during processing without positively mixing a reaction gas for metal or semiconductor.
When a composite material of an organic substance and a metal is actually processed under the condition of only an inert gas such as e or Ar, the result is obtained that the organic material can be selectively processed with respect to the metal or the semiconductor. It was

[0012] In the present invention, other inert gas as the atmosphere gas, air, N _2, O ₂ can be used, also,
It is also possible to use a mixture of these with an inert gas. The ratio in the case of mixing air, N ₂ and O ₂ with the inert gas may be arbitrary. Furthermore, CF ₄ and SF ₆ are added to the inert gas.
The processing speed can be improved by mixing up to several% (volume ratio).

[0013]

Embodiments of the processing method of the present invention will be described below with reference to the drawings. First, an apparatus used to carry out the processing method of the present invention will be described. FIG. 1 is a block diagram showing a schematic configuration of the processing apparatus, and FIG. 2 is a perspective view showing a processing electrode 2 and a linear stage 3 of the apparatus in an extracted manner.

Inside the reaction vessel 1, a linear stage 3 holding a workpiece (organic material) W and a processing electrode 2 located above the linear stage 3 are arranged. The high frequency power supply device 5 is connected via.
The high frequency power supply device 5 has a power of a frequency of 100 MHz or more,
For example, high frequency power of 145 MHz and 240 W is applied to the machining electrode 2
It is a power supply device that can be applied to.

The reaction container 1 is provided with a nozzle 1a between the workpiece W on the stage 3 and the machining electrode 2. An inert gas such as He is supplied from the gas supply device 6 to the nozzle 1a at a constant flow rate. Further, the reaction container 1 is connected to an exhaust device 7 for reducing the internal pressure of the container to about 0.1 Torr.

A specific example of carrying out the method of the present invention using the above processing apparatus will be described below. First, a sample in which a polyimide having a thickness of 20 μm is laminated on the surface of a Si wafer is placed as a workpiece W on the linear stage 3, and the machining electrode 2 has a thickness of 0.125 mm and a length of 30 mm. Using a flat plate made of Al, this machining electrode 2 and the workpiece W
Set the gap between the top surface of polyimide and 0.2mm.

Next, the pressure inside the reaction vessel 1 was reduced to about 0.1 Torr, and then He gas was filled into the vessel and the pressure was maintained at 1 atm.
High-frequency power of 40 W is applied, and He gas is flown between the electrode 2 and the workpiece W through the nozzle 1a at a flow rate of 10 (liter / minute) while scanning the linear stage 3 at 12 mm / minute. When flat surface processing was performed in a state of flowing in parallel with 2, the processing amount (shaving depth) was about 0.2 μm,
The surface roughness was 0.005 μm (Rmax) or less, and very smooth precision machining could be performed.

In the above flat surface processing, the conditions of the processing atmosphere gas were changed and He gas was replaced with 3% by volume of O ₂
When the processing was performed with the gas mixed, the processing amount was about twice as deep as in the case of the He gas only atmosphere, but the result was that the surface roughness was deteriorated.

Further, the same workpiece W as in the previous embodiment is placed on the linear stage 3, and a metal mask (having a thickness of 0.025 mm and a corner of 0.1 mm is placed on the processed surface of the workpiece W). When a copper mesh with square holes opened at a pitch of 0.125 mm) was placed, and processing was performed for 5 minutes under the same conditions as above, the copper mesh was not processed at all, and only the polyimide mesh By processing according to the opening shape, a square hollow hole as shown in FIG. 3 could be opened. At this time, even if the polyimide P was completely removed by processing and the surface of the Si wafer S was exposed to radicals, the surface of the wafer was not processed at all.

Next, an example in which the method of the present invention is applied to the processing of a wiring board (a laminated body of copper and polyimide) will be described with reference to FIG. First, the wiring board F1 has a thickness of 50 μm.
After a copper foil having a thickness of 40 μm is adhered on the polyimide film P1 of No. 1 with an adhesive containing epoxy resin as a main component,
A fine line pattern C1 having a line width of 0.2 mm is obtained through a patterning process using a photoresist, a copper foil etching process using an acidic etching solution, and a photoresist removing process.
After obtaining the above, a polyimide film P1 is further laminated on the pattern using an adhesive E1.

Also in this example, the processing is carried out using the apparatus shown in FIG. 1 under the same conditions as above, but the wiring board F1 which is the object to be processed is as shown in FIG. 4 (a). Then, the fine line pattern C1 is placed on the stage 3 so as to be orthogonal to the machining electrode 2, and the positional relationship between the wiring board F1 and the machining electrode 2 is fixed without scanning by the stage 3. When processed with, as shown in Fig. 4 (b),
It was possible to remove only the adhesive E1 and the polyimide film P1 around the fine line with almost no influence on the fine line pattern C1 made of copper. Therefore, by adopting such a processing method, even in a wiring board having a structure in which a fine line pattern is embedded, the fine line pattern can be exposed, that is, the contact portion of the pattern can be easily formed.

Next, an example in which the method of the present invention is applied to the processing of the inner wall surface of the through hole opened in the laminated body of copper and polyimide will be described with reference to FIGS. 5 (a) and 5 (b). Note that FIG. 5 shows a state in which the through hole H is cut at the central position.

First, a laminate F2 which is a workpiece is formed by alternately laminating a copper foil C2 having a thickness of 40 .mu.m and a polyimide film P2 having a thickness of 50 .mu.m with an adhesive (mainly epoxy resin) E2 interposed therebetween. A through hole H having a diameter of 0.6 mm is opened. Further, in this processing example, the through hole H is arranged immediately below the processing electrode, and since the gas containing radicals at the time of processing is introduced into the through hole H, the atmospheric gas (He gas) is used as the nozzle 1a. While letting it flow into the hole from
When the inner wall of the hole was processed, as shown in FIG. 5 (b), the copper foil C2 was not processed at all, and the polyimide film P
Only 2 and adhesive E2 were removed. Therefore, such a processing method is an extremely advantageous method for the workability of the through hole plating which is the next step.

That is, after forming through holes (drilling etc.) in the laminate of the copper foil and the organic film,
Since the copper foil on the hole processing surface is dirty due to the adhesion of an adhesive, and the copper foil processing surface on the hole inner surface is flush with the film processing surface, it remains as it is. When through-hole plating is applied, poor adhesion of the copper plating to the copper foil, and more likely to cause contact failure due to causes such as plating edge breakage at the boundary between the copper foil and the film. by performing the hole drilling, adhesive adhered to the copper foil of the holes machined surface was completely removed, moreover, as shown in FIG. 5 (b), a copper foil C2 in hole inner surface, the polyimide film P ₂ and adhesive Since it is in a state of protruding with respect to the agent E2, the state of deposition of copper on the copper foil C2 at the time of plating is favorable, and as a result, the workability of through-hole plating is improved.

Here, the pressure of the gas atmosphere at the time of processing is 1/100 atm or higher as described above, but there is no problem, but the upper limit thereof is taken into consideration in consideration of the processing selectivity for metal or semiconductor. About 1 atm is preferred.

Further, as the processing electrode used for carrying out the processing method of the present invention, in addition to the flat plate electrode shown in the above embodiment, for example, a wire electrode in which a metal wire is stretched linearly or a needle electrode is used. Any shape can be used as long as it can concentrate plasma discharge in a minute area. In addition, by matching the two-dimensional shape of the discharge surface of the processing electrode with a desired processing shape, it is possible to perform processing along that shape. For example, as shown in FIG.
By making the cylindrical shape, circular punching can be performed.

It is needless to say that the method of the present invention is not limited to processing of highly functional organic materials such as polyimide, but can be applied to processing of a wide range of organic materials including general organic materials. Yes.

[0028]

As described above, according to the processing method of the present invention, the radical reaction is utilized in the processing of the organic material, so that the surface roughness of the processed surface is, for example, about 0.005 μm. It becomes possible to do it without distortion. Further, neither a thermally deteriorated layer nor a surface deteriorated layer due to ion bombardment is generated in the processed portion. Moreover, even for highly functional organic materials such as polyimide, it is possible to perform such strain-free ultra-precision processing, which enables the production of composite materials (parts) of highly functional organic materials and metals. Can achieve ultra-precision.

Further, since the processing is basically based on the radical reaction, the degree of freedom of processing is high. As a result, not only the surface processing but also the outer shape (contour) processing, the hollowing of the recessed hole, or the inside of the through hole is performed. It can be applied to various kinds of processing such as wall processing. Furthermore, it is possible to selectively process metal or semiconductor, which makes it possible to easily process an organic material into a desired pattern simply by disposing a metal mask on the object to be processed. Has a great effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an apparatus used for carrying out a processing method of the present invention.

[FIG. 2] Processing electrode 2 and linear stage 3 of the processing apparatus
Perspective view showing the extracted

FIG. 3 is a diagram illustrating an embodiment of a processing method of the present invention.

FIG. 4 is a diagram for explaining another embodiment.

FIG. 5 is a diagram for explaining still another embodiment.

FIG. 6 is a view showing a modified example of a working electrode used for carrying out the method of the present invention.

[Explanation of symbols]

1 ... Reaction container 1a ... Nozzle 2 ... Machining electrode 3 ... Linear stage 4 ... Matching device 5 ··· High frequency power supply 6 ... Gas supply device 7 ... Exhaust device W ・ ・ ・ ・ Workpiece (organic material)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsukasa Miyazaki 1-2-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Inventor Shuji Yano 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture No. Nitto Denko Corporation (72) Inventor Yuzo Mori 8-16-9 Private City, Katano City, Osaka Prefecture (56) Reference JP-A-5-255871 (JP, A) JP-A-1-319942 ( JP, A) JP 1-125829 (JP, A) JP 56-69382 (JP, A) JP 5-57525 (JP, A) JP 4-72725 (JP, A) JP 5-195258 (JP, A) JP-A-56-81678 (JP, A) JP-A-62-111429 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23H 1 / 00 B23K 10/00 C08J 7/00 C23F 4/00 H05K 3/26

Claims (6)

(57) [Claims] 1. A into the reaction vessel inside the processing electrode is disposed, the organic materials as well as disposed with a predetermined gap with respect to the electrode, the vessel, and a gas atmosphere 1 /
High-frequency power is applied to the electrode while maintaining at 100 atm or more and 1 atm or less , plasma is generated between the electrode and the organic material, and the reaction between radicals in the plasma and the organic material is used. A method of processing an organic material that performs processing. 2. The method of processing an organic material according to claim 1, wherein the organic material is processed in a state where a metal mask having a predetermined pattern is arranged on the processed surface of the organic material. 3. The organic material according to claim 1, wherein the electrode is scanned along a processing surface of the organic material by the relative movement of the processing electrode and the organic material. Processing method. 4. The method of processing an organic material according to claim 1, wherein the composite material of a metal substance and an organic substance is processed. 5. The processing of the organic material according to claim 1, wherein the organic material formed on the surface of any one of a metal, a semiconductor, and an inorganic insulator is processed. Method. 6. The processing of an organic material according to claim 1, wherein the gas containing the radical is introduced into the through hole opened in the organic material to process the inner wall surface of the through hole. Method.