WO2004044971A1

WO2004044971A1 - Method and device for polishing plasma chamber cathode holes

Info

Publication number: WO2004044971A1
Application number: PCT/KR2002/002093
Authority: WO
Inventors: Jae-Keuk Chung
Original assignee: Worldex Int
Priority date: 2002-11-09
Filing date: 2002-11-09
Publication date: 2004-05-27
Also published as: AU2002353591A1

Abstract

The present invention relates to the plasma chamber cathode that has minute holes (21) of less than 0.5mm in diameter and made of a silicon plate of a certain thickness. The present invention is designed to provide the cathode which can flow the gas into the plasma chamber in a stable way by polishing the surface of the cathode in the chamber which is used to process the semiconductor wafer. The cathode is fixed with jigs which are made of abrasion-proof metal and has the same hole disposition as the said cathode (20). The jetter (30) has easy-to-open upper cover and has many jet nozzles (31) arrayed inward at regular intervals. The said jetter (30) is installed on the upper part of the main body (40) with a certain space and the jet nozzles (31) of each jetter(30) are interlocked with the compressor (50) and the pump (60). The polishing solution tank (70) under each jetter (30) is linked to the said pump (60). The said cathode (20) is fixed on the jetter (30) that has jet nozzles on it. The polishing solution is injected with air at a certain pressure through the said jet nozzles (31). Then the solution goes through the cathode holes, guided by jig (a) holes on both sides, and polishes the surface.

Description

Method and Device

for Polishing Plasma Chamber Cathode Holes

Technical Field

The present invention relates generally to the plasma chamber

cathode used for semiconductor wafer plasma processing, and more

particularly to the plasma chamber cathode hole polishing method and

the device for precise processing of the cathode hole surface through

which gas moves in plasma processing, thereby improving the

semiconductor wafer etching process efficiency and cathode durability.

Background Art

As illustrated in Fig. 1 and Fig. 2, the cathode used for

semiconductor etching is generally made of a silicon plated 0) of a

certain diameter and thickness, on which via holesd 1 ) are densely

arrayed at regular intervals.

The cathode is made by the following procedure: A silicon

column is cut into a certain thickness by a cutter. The surface and the

circumference of the severed silicon is processed to make a plate on which holesd 1 ) of less than 0.5mm in diameter are punctured by a

drilling machine that uses diamond drills. Then the plate 0) is put in

an acid tank to corrode the surface of the holes.

The plate provided by the procedure given above is installed

on the upper part of the semiconductor elements in the plasma

chamber. Next, gas is injected to pass through the holes and etch the

surface of the semiconductor elements.

This existing method of putting the cathode in the acid and

then, depending on the chemical reaction for surface corrosion, has

resulted in a coarse surface, as shown in Fig. 4, which increases the

resistance of gas passing through the holes and spreads the gas flow,

preventing precise etching. The irregular cathode hole surface also

produces particles during the gas inflow which streams into the plasma

and poses problems in improving the processing efficiency.

To solve the problem of drill polishing, Appl. No. 0299975

"Plasma Chamber Electrode Manufacturing Method" suggests using

ultrasonic waves instead of a diamond drill to pierce holes on the

silicon cathode plate. The detailed procedure is as follows: The silicon

plate is faced against the drilling plate that has many projected tips. Abrasives are supplied to both the drilling plate and the silicon plate,

and ultrasonic waves are applied to the drilling plate. The continuous

vibration of the tips makes the abrasive particles pierce the plate. This

ultrasonic drilling technology is a new method completely different from

the existing drilling technology. Therefore the current diamond drill

users have to make a substantial initial investment to acquire new

machines and technology.

In this regard new technology needs to be provided which

uses the existing diamond drill technology but still can make minute

perforations and polish the holes precisely.

Disclosure of Invention

In order to solve the problem presented above, the present

invention installed many jet nozzles(31 ) on the jetter(30) which operates

together with the compressor(50) and the pump(60) at the bottom of

the main body that has an easy-to-open cover, and linked the tank of

polishing solutions under each jetter(30) to the upper pump(60). After

securing the cathode, which was primarily perforated using the diamond

drill, with jigs(a) and fixing it on the jetter(30) that is lined with jet nozzles(31 ), the invention injected the polishing solution and air with a

certain amount of pressure to make the solution pass through the fixing

jigs and polish the cathode hole surface. The present invention was

designed to provide a more effective and durable cathode by

minimizing contamination inside the chamber as well as minimizing the

resistance that occurs when gas is injected through the cathode for

more precise wafer etching.

The present invention, by the devices and method demonstrated

above, precisely processes and smoothens the plasma chamber

cathode hole surface with the polishing solution. More stable fluid

flowing and less resistance in gas influx guarantees a more precise

etching formation on the semiconductor elements and excellent cathode

durability with decreased hole interior transformation. Furthermore, the

simple equipment and pollutant decreasing effect will lead to cost

saving and environment protection. In short, the invention is expected

to have many great properties.

Brief Description of the Drawings

Fig. 1 is a block diagram and a cross section depicting the ordinary cathode.

Fig. 2 is a cross section depicting gas injection through the

plasma chamber cathode.

Fig. 3 is a cross section depicting the cathode combined with

jigs in accordance with a right embodiment of the invention.

Fig. 4 is a block diagram depicting the cathode hole processing

device in accordance with a right embodiment of the invention.

Fig. 5 is a partial cross section depicting the jetter (30) of the

cathode hole processing device in accordance with a right embodiment

of the invention.

Fig. 6 is an enlarged photograph depicting the cathode hole

surface after primary drilling in accordance with a right embodiment of

the invention.

Fig. 7 is an enlarged photograph depicting the cathode hole

surface.

description on the symbols of the major parts in the drawings>

20: cathode 21 : cathode hole 30: jetter

31 : jet nozzle 32: cover 40: main body 50: compressor 60: pump 70: tank

a: jig 1 a: jjg hole

Best Mode for Carrying Out the Invention

Fig. 1 is a block diagram and a cross section depicting the

ordinary cathode; Fig. 2 is a cross section depicting gas injection

through the plasma chamber cathode; Fig. 3 is a cross section of

the cathode combined with jigs showing a right embodiment of the

invention; Fig. 4 is a block diagram of a cathode hole processing

device showing a right embodiment of the invention; Fig. 5 is a partial

cross section illustrating the jetter(30) of the cathode hole processing

device in accordance with a right embodiment of the invention; Fig. 6

is an enlarged photograph depicting cathode hole surface after primary

drilling in accordance with a right embodiment of the invention; Fig. 7

is an enlarged photograph depicting the cathode hole surface. The

detailed description of the present invention, plasma chamber cathode

hole polishing method and device is as follows.

As shown in Fig. 4, 5, and 7, the cathode, perforated first with

the drilling machine, is fixed on the jetter (30), with jet nozzles (31 ) on it, of the hole processing device using jigs, which is larger than the

cathode holes. The jig is made from an abrasion-proof metal material

which is perforated to match up with the cathode holes in terms of

location, disposition, structure and number. The jigs are stuck fast to

the either side of the primarily processed cathode to match up with the

holes and put on the jetter(30). Then, allowing some space, the main

body cover is made to secure the cathode by pressing the jigs and

prevent the outflow of the injected solution.

As described above, an easy-to-open cover of the main body

facilitates attaching/detaching of the cathode (20) and jigs (a). Several

jetters (30), on which several jet nozzles (31 ) are disposed inward at

regular intervals, are installed on the lower surface of the main body.

The jet nozzles (31 ) on each jetter (30) are linked to the compressor

(50) and the pump (60). A tank of polishing solutions is placed under

each jetter (30) in the main body to operate together with the pump

(60). The polishing solution, guided by the jig (a) holes, goes through

the cathode (20) holes (21 ), escapes from the main body and collects

in the tank (70) by way of the recovery passage.

The upper side of the jetter (30) is connected with a transparent cover and an outer tank (The drawing is omitted.), on the lower part of

which is the recovery passage, is installed inside. On the outer surface

of the upper side of the jetter (30) are clamps (The drawing is

omitted.) that lock up the outer part of cathode securing the jigs(20).

The recovery passage of the outer can, mentioned above is interlocked

with the tank(70).

The description of the present polishing method is as follows:

After holes (21 ) are made on the cathode (20) with the drilling

machine, the cathode is put on the upper side of the jetter (30) with

its holes corresponding to the jig holes, and the outer part is secured

with clamps. When the power is on, the pump (70) and the pressure

(30) start to send the polishing solution in the tank (70) into the jetter

(30) through jet nozzles (31 ) with a certain amount of pressure and

high-pressure air transferred from the compressor(50), passing through

the jet nozzles(31 ), sprays the polishing solution into the jetter(30)

above a certain angle.

The injected polishing solution, guided by the jig(a) holes a)

fixed on the jetter(30), goes through cathode(20) holes(21 ) and

polishes the surface by means of friction. The solution that has passed through the holes(21 ) is collected in the outer can and sent back to

the tank(70) by the way of the recovery passage for the next

circulation. In this cathode hole polishing process, jigs(a) serve to

guide the solution, injected through the jetter(30), to cathode holes as

well as protect the cathode area that doesn't need polishing by

combining with the area.

Besides the present invention allows the same, except for the

size of polisher particles, processing to be repeated several times in

order to polish hole surface more precisely. As the procedure goes to

the final step, the particles of the solution that processes the holes

become smaller to make the surface in the holes smooth as shown in

Fig. 6.

The polishing procedure of the hole processing device given

above is made up of four or more steps. The polishing solution is the

ordinary solution made from water, SIC and cutting oil at the ratio of

10:2:1 . In the repeated processing, the size of particles is adjusted in

each step and for the purpose of the perfect polishing the minutest

polisher is chosen in the last processing as illustrated in Fig. 6. The

size of SIC powder particles flowed into the tank(70) in the final stage is as minute as upwards of 6000 meshes.

Claims

What is Claimed Is:

1. A method of polishing the minute holes(21 ) of less than

0.5mm in diameter on the cathode, a silicon plate of a certain

thickness, of the plasma chamber which is used to process the

semiconductor wafer, the method comprising:

the said cathode(20) is fixed on the jetter(30), which has

jet nozzles(31 ) on it, with jigs(a); the polishing solution and air is

injected with a certain pressure through the said jet nozzles(31 ); and

the solution goes through the said cathode holes(21 ) and polish the

hole surface.

2. A method of polishing the minute holes(21 ) of less than

0.5mm in diameter on the cathode, a silicon plate of a certain

thickness, of the plasma chamber which is used to process the

semiconductor wafer, the method comprising:

the easy-to-open upper part make it simple to attach or

detach the said cathode(20); many jetters(30), on the surface of which

several jet nozzles are arrayed inward at regular intervals, are installed on the upper part of the main body with a certain space; detachable

jigs and the jet nozzles(31 ) of each of the said jetters(30) are

interlocked with the compressor(50) and the pump(60); and the

tank(70) of the polishing solution under each jetter(30) is linked to the

said pump(60) to operate together.

3. The method and device of claim 1 or 2 wherein the

polishing solution is made from water, silundum(SiC) and cutting oil.

4. The method and device of claim 1 or 2 wherein the

cathode(20), primarily perforated with the drilling machine, is fixed with

the jigs, which is made from abrasion-proof metal material and has

holes bigger than those of the cathode, by corresponding the cathode

holes(21 ) to the jig holesd a).

5. The method and device of claim 1 or 2 wherein the same

polishing procedure is repeated several times to polish the cathode

hole surface with variation in the size of polisher particles.

6. The method and device of claim 2 wherein the jetter(30)

is installed within the outer can(32) and the recovery passage on the

lower part of the said outer can is linked to the tank(70) to operate

together.