KR100249387B1 - Foreign substance removal method for dry etching apparatus for semiconductor manufacturing - Google Patents

Abstract

The present invention relates to a foreign material removal method of a dry etching apparatus for manufacturing a semiconductor device, which is cleaned and removed by a working gas which interacts with metallic foreign matter remaining in a process chamber during an in-situ cleaning performed after a wafer etching process is completed. Cleaning is effective in removing photoresist polymers, but metallic polymers such as Ti and Al based polymers and Al ₂ O ₃ polymers generated by sputtering inside the processing chamber cannot be removed. The present invention has a problem of lowering the yield by affecting the wafer in which the polymer is etched. Thus, in order to remove a metal-based polymer remaining in the process chamber during etching, a reaction gas having high mutual bonding property is introduced into the process chamber. Various metals generated during metal film etching by in-situ cleaning With the advantage that by removing the foreign matter efficiently prevent reduction in the yield of the wafer due to the foreign matter in advance for semiconductor manufacturing is the key impurity removing method of the etching apparatus.

Description

Foreign body removal method of dry etching device for semiconductor manufacturing

The present invention relates to a foreign material removal method of a dry etching apparatus for manufacturing a semiconductor. More specifically, the present invention relates to a working gas that interacts with metallic foreign matter remaining in a process chamber during IN SITU cleaning performed after a wafer etching process is completed. The present invention relates to a method for removing foreign substances in a dry etching apparatus for manufacturing semiconductors by cleaning.

In general, in an ECR (Electron cyclotron resonance) type metal etching apparatus which is an equipment for etching an aluminum metal film _, process gases such as BCl _{3 and} Cl ₂ are used to etch the aluminum metal film formed on the wafer surface.

Therefore, the metal-based polymer by the process gas is composed of Ti, Al-based polymer generated in the film, and Al ₂ O ₃ polymer and photoresist-based polymer generated by sputtering the inside of the processing chamber made of a ceramic-based material.

In situ cleaning is often performed to remove the polymer in the process chamber.

At this time, the in-situ cleaning is performed by moving the wafer which has been etched to the strip chamber and before the next wafer is mounted in the empty process chamber, O ₂ gas is introduced and co-discharged with microwaves. It is to remove foreign substances in the body.

The process chamber in which the conventional in-situ cleaning is performed includes a waveguide 1 through which microwaves are introduced as shown in FIG. 1, and an inlet pipe 3 and an outlet pipe 5 formed at both ends thereof so that the process gas flows in and out. And a wafer chuck 7 of ceramic material Al ₂ O ₃ on which a wafer (not shown) is seated and fixed on an upper surface thereof, and a stage 9 on which the wafer chuck 7 is installed.

In-situ cleaning in the process chamber is performed by applying a RF (Ratio frequency) to the process chamber and supplying O ₂ gas through the inlet tube (3) in the state where microwaves are supplied from the waveguide (1). They work chemically with each other to remove the polymer in gaseous form.

In this case, the photoresist-based polymer is made of C, and thus is released through the discharge pipe 5 in the state of CO ₂ by interacting with O ₂ gas.

This reaction occurs in a process chamber in which 100 sccm of O ₂ gas enters the process chamber maintaining a pressure of 16 mT and interacts with microwaves of about 300 mA for 20 seconds.

However, conventional in-situ cleaning is effective in removing photoresist polymers, but metallic polymers such as Ti and Al based polymers generated in the film and Al ₂ O ₃ polymers generated by sputtering inside the process chamber There is a problem in that the yield is reduced by remaining in the process chamber and not affecting the wafer to be etched.

SUMMARY OF THE INVENTION An object of the present invention is to provide a foreign material removal method of a dry etching apparatus for manufacturing a semiconductor, in which an inert cleaning reaction gas is introduced into the process chamber to remove metal-based polymer remaining in the process chamber during etching. There is.

Therefore, the present invention, in order to achieve the above object, the RF is applied to the process chamber, the microwave is transmitted through the waveguide into the process chamber and the reaction gas flows through the inlet pipe formed on one side to interact with the remaining inside the process chamber In the in-seat cleaning operation of the etching apparatus in which foreign matter is discharged through the discharge pipe, the reaction gas is a step of reacting with the Ti, Al-based polymer in the process chamber with Cl ₂ gas, and the reaction gas is O ₂ gas And two steps of mutual reaction with the photoresist-based polymer in the furnace process chamber, and _three steps of the reaction gas interacting with the polymer of Al ₂ O ₃ with a mixed gas of BCl ₃ gas and Cl ₂ gas. .

1 is a use state diagram showing a conventional dry etching process,

2 is a state diagram showing the dry etching process of the present invention.

Explanation of symbols on the main parts of the drawings

1: waveguide, 3: inflow pipe,

5: discharge pipe, 7: wafer chuck,

9: stage.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

2 is a state diagram showing the dry etching process of the present invention.

In-process cleaning is performed in the empty process chamber after the wafer (not shown) having been etched in the process chamber is transferred to the strip chamber (not shown).

In the in-situ cleaning process, first, RF is applied to the process chamber so that microwaves are transmitted through the waveguide 1 into the process chamber and the reaction gas flows through the inlet tube 3 formed on one side to interact with the inside of the process chamber. Remove foreign substances remaining in the

Reaction gases introduced during the in-situ cleaning are Cl ₂ , O ₂ and BCl _3. First, Cl ₂ gas is introduced into the process chamber maintaining a pressure of about 8 to 16 mT at a rate of about 100 to 200 sccm. 1 step to remove Ti and Al series polymer by reacting for about 5 ~ 10 seconds with 300mA microwave applied, and about 100 ~ 200 sccm of O ₂ gas into process chamber with pressure of about 8 ~ 16mT 2 steps to remove the photoresist polymer by reacting and cleaning for about 5 to 10 seconds while being supplied with microwave of 200 to 300 mA, and about 100 to 200 sccm with BCl ₃ gas of about 100 to 200 sccm The Cl ₂ gas is introduced into the process chamber with a pressure of 8 to 16mT, and reacts for about 10 to 20 seconds in a state where microwaves of 200 to 300mA are applied to remove Al ₂ O ₃ polymer.

In this case, each of the steps may not be performed sequentially, but may be performed first.

In each step, the reaction equation is first released from the discharge tube in the form of Tix + Cl _Y = TixCl _{Y ↑} in which Ti remaining in the chamber and the Cl ₂ gas react with each other in the first step where the Cl ₂ gas is introduced. In addition, Al and Cl ₂ gas reacts with each other and Al + Cl = Alx + Cl _{Y ↑} is discharged.

Meanwhile, in the second step, a large amount of C-based polymer generated by etching the photoresist formed on the wafer and O ₂ gas introduced into the process chamber react with each other to be released in the form of C + O _{2 =} CO _{2 ↑} .

In addition, in the third step of the BCl ₃ gas and a Cl ₂ flow into the Al ₂ O ₃ based polymer and the process chamber is generated while sputtering the ceramic part within the process chamber, the interaction Al ₂ O ₃ + BCl ₃ + Cl ₂ = Al _The polymer is removed by interacting with _X Cl _{Y ↑} + B _X O _{Y ↑} .

As described above, according to the present invention, in order to remove the metal-based polymer remaining in the process chamber during the etching operation, various reactions generated during the etching of the metal film by introducing the reactive gas having high mutual coupling into the process chamber and in-situ cleaning are performed. Effective removal of metallic foreign matters has the advantage of preventing the yield reduction of the wafer due to foreign matters.

Claims (4)

When RF is applied to the process chamber, microwaves are transmitted through the waveguide 1 into the process chamber, and reaction gas flows through the inlet pipe 3 formed on one side to interact with the foreign matter remaining inside the process chamber. In the in-sheet cleaning of the etching apparatus discharged through the), A first step of reacting the reaction gas with a Ti, Al-based polymer in the process chamber with Cl ₂ gas; Step _{2 in which} the reaction gas reacts with the photoresist-based polymer in the process chamber with O ₂ gas; The foreign matter removal method of the dry etching apparatus for manufacturing a semiconductor, characterized in that the reaction gas is a mixed gas of BCl ₃ gas and Cl ₂ gas with three steps of mutual reaction with the polymer of Al ₂ O ₃ . The method according to claim 1, wherein the first step, 100 ~ 200sccm Cl ₂ gas is introduced into the process chamber with a pressure of 8 ~ 16mT to remove foreign substances of the dry etching apparatus for semiconductor manufacturing, characterized in that reacted for about 5 ~ 10 seconds in the state that the microwave of 200 ~ 300 mA is applied Way. The method according to claim 1, wherein the second step, O ₂ gas of 100 ~ 200sccm is introduced into the process chamber with a pressure of 8 ~ 16mT to remove foreign substances in the dry etching apparatus for semiconductor manufacturing, characterized in that reacted for about 5 ~ 10 seconds in the state of applying a microwave of 200 ~ 300 mA Way. The method according to claim 1, wherein the three steps, 100 to 200 sccm of BCl ₃ gas and 100 to 200 sccm of Cl ₂ gas are introduced into the process chamber having a pressure of 8 to 16 mT, and react for about 10 to 20 seconds while applying microwave of 200 to 300 mA. Foreign body removal method of dry etching apparatus for semiconductor manufacturing.

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