TW201346059A - Cleaning method for MOCVD equipment - Google Patents

Abstract

Disclosed is a cleaning method for MOCVD equipment, which includes: following cleaning gases into a reaction chamber of the MOCVD equipment; using a plasma processing device to ionize said cleaning gases; rising the temperature of an inner wall of the reaction chamber to 50℃~250℃; and using the plasma of said cleaning gases to clean the inner wall of said reaction chamber at said temperature. The cleaning method according to the present invention can automatically clean residual deposits on the inner wall of the MOCVD reaction chamber; the plasma of said cleaning gases does not cause damage to the inner wall of said MOCVD reaction chamber; and this cleaning method has a short cleaning time.

Description

Method for cleaning MOCVD equipment

The present invention relates to the field of semiconductor manufacturing, and in particular to a method of cleaning an MOCVD device.

Currently, the metal organic compound chemical vapor deposition (MOCVD) process is a common process for forming Group III elements and Group V element compounds. The MOCVD process is generally performed in a MOCVD reaction chamber having a higher temperature, and a first reaction gas containing a Group III element and a second reaction gas containing a Group V element are introduced into the MOCVD reaction chamber, and a substrate is disposed on the susceptor in the MOCVD reaction chamber, and the first reaction gas and the second reaction gas react on a surface of the substrate at a higher temperature to form a group III element and a group V element compound on the surface of the substrate. film.

However, while the film is formed on the surface of the substrate by the MOCVD process, residual deposits are formed on the inner wall of the reaction chamber, the surface of the gas shower head, and the surface of the susceptor. These residual deposits may generate impurities in the reaction chamber and may peel off from the adhesion, and may eventually fall on the substrate to be processed, causing defects in the film formed on the surface of the substrate, affecting the electrical properties of the finally formed semiconductor device. . Thus, after a period of MOCVD thin film deposition process, the deposition process must be stopped and the residual deposits in the reaction chamber removed using a chamber cleaning process.

At present, the reaction chamber cleaning process commonly used in the industry is usually "manual cleaning", specifically: stopping the MOCVD process, reducing the internal temperature of the reaction chamber to a certain temperature; opening the reaction chamber, removing the substrate; using a brush to adhere to the reaction chamber Inner wall, surface of gas shower head The residual deposit is brushed from its attachment surface and the reaction chamber is removed; the susceptor to which the residual deposit is attached is removed from the reaction chamber and replaced with a new, clean susceptor. However, the cleaning method must be used to stop the original film deposition process, and the reaction chamber can be opened for cleaning after the temperature in the reaction chamber drops to a temperature suitable for manual cleaning, and the reaction chamber needs to be heated after the cleaning process is completed. The specific reaction temperature is used to carry out the MOCVD process. Since the MOCVD apparatus cannot deposit a film during manual cleaning, the cooling and temperature rising process requires a large amount of time, so that the production efficiency and productivity of the MOCVD apparatus cannot be maximized. Moreover, since the cleaning method is manual cleaning, the operator not only needs to manually remove residual deposits, but also increases the working intensity of the operator, and the degree of cleaning is inconsistent each time, and the residual deposit may not be cleaned due to operator error. Clean, residual deposits may eventually fall on the substrate to be processed later, causing defects in the film formed on the surface of the corresponding substrate, affecting the electrical properties of the finally formed semiconductor device.

The problem solved by the present invention is a cleaning method for an MOCVD apparatus capable of automatically and quickly cleaning residual deposits on the inner wall of an MOCVD reaction chamber.

In order to solve the above problems, the present invention provides a cleaning method for an MOCVD apparatus, comprising: introducing a cleaning gas into a reaction chamber of the MOCVD apparatus; plasma-cleaning the cleaning gas by a plasma processing apparatus; The temperature of the wall rises to 50 ° C to 250 ° C at which the inner wall of the reaction chamber is cleaned with a plasma of a cleaning gas.

Preferably, the temperature of the inner wall of the reaction chamber is raised to 200 ° C to 250 ° C at which the inner wall of the reaction chamber is cleaned with a plasma of a cleaning gas.

Preferably, the MOCVD device has a gas shower head at the top of the reaction chamber, and the gas shower head has a shower head cooling device therein.

Preferably, while the inner wall of the reaction chamber is cleaned by the plasma of the cleaning gas, no liquid is introduced into the shower head cooling device.

Preferably, while the inner wall of the reaction chamber is cleaned by the plasma of the cleaning gas, a high temperature liquid is introduced into the shower head cooling device, so that the temperature of the surface of the shower head rises to 50 ° C. 250 ° C.

Preferably, the material of the high temperature liquid is a heat transfer oil, a molten salt or water.

Preferably, the plasma processing apparatus includes an inductively coupled plasma processing apparatus and a capacitively coupled plasma processing apparatus.

Preferably, the power of the plasma processing apparatus is greater than or equal to 1000 W, and the inner wall of the reaction chamber is heated by thermal energy generated by the plasma.

Preferably, the cleaning gas includes at least a first cleaning gas for chemical cleaning, and the first cleaning gas includes at least a Cl element.

Preferably, the first cleaning gas is one of or a combination of Cl ₂ and HCl.

Preferably, the cleaning gas further includes a second cleaning gas for physical cleaning, and the second cleaning gas is one or a combination of two of Ar, N ₂ .

Compared with the prior art, the technical solution of the present invention has the following advantages:

In the cleaning method of the MOCVD apparatus according to the embodiment of the present invention, the heat generated by the plasma cleaning gas is used to raise the temperature of the inner wall of the reaction chamber to 50 ° C to 250 ° C, and the reaction is cleaned by the plasma of the cleaning gas at the temperature. Inner wall of the cavity. As the temperature increases, the rate of removal of residual deposits on the inner wall of the reaction chamber by the plasma of the cleaning gas is also gradually increased, and the reaction chamber is cleaned by plasma using a cleaning gas at a temperature of 50 ° C to 250 ° C. The wall can automatically remove residual deposits from the inner wall of the MOCVD reaction chamber, the plasma of the cleaning gas does not cause damage to the inner wall of the MOCVD reaction chamber, and the cleaning takes a short time.

Further, during the cleaning process of the reaction chamber of the MOCVD apparatus, a constant circulating hot liquid is introduced into the shower head cooling device, so that the temperature of the surface of the gas shower head rises to 50 ° C to 250 ° C. The heat generated by the high temperature liquid and the heat generated by the plasma of the cleaning gas act on the gas shower head, and the power of the radio frequency signal generated by the radio frequency supply source can be small, thereby saving the cleaning process of the reaction chamber of the MOCVD device. The energy consumed in it.

The specific embodiments of the present invention will be further described by the following examples and the accompanying drawings.

110‧‧‧Reaction chamber

111‧‧‧ side wall

112‧‧‧ bottom

113‧‧‧ top

115‧‧‧Base

120‧‧‧ gas sprinkler

125‧‧‧Cooling device

131‧‧‧RF source

132‧‧‧RF matcher

140‧‧‧Air pump

141‧‧ vent

231‧‧‧RF source

232‧‧‧RF matcher

331‧‧‧RF source

332‧‧‧RF matcher

350‧‧‧Inductance coil

1 is a schematic flow chart of a cleaning method of an MOCVD apparatus according to an embodiment of the present invention; FIGS. 2 to 4 are schematic views showing the structure of an MOCVD apparatus according to an embodiment of the present invention; and FIG. 5 is a plasma cleaning using the cleaning gas at different temperatures. A comparison of the results of the rate of sediment.

As mentioned in the prior art, the manual cleaning of residual deposits on the inner wall of the MOCVD reaction chamber requires not only a large amount of time, but also the production efficiency and productivity of the MOCVD equipment cannot be maximized, and the degree of manual cleaning is cleaned each time. Inconsistent, residual deposits may not be cleaned up due to operator error.

To this end, the inventors have proposed a cleaning method for an MOCVD apparatus, comprising: introducing a cleaning gas into a reaction chamber of the MOCVD apparatus; plasma-cleaning the cleaning gas by a plasma processing apparatus; The temperature is raised to 50 ° C to 250 ° C at which the inner wall of the reaction chamber is cleaned with a plasma of a cleaning gas. The inventors have found through research that as the temperature increases, the cleaning rate of the residual gas on the inner wall of the reaction chamber is gradually increased by the plasma of the cleaning gas, and is cleaned by plasma using a cleaning gas at a temperature of 50 ° C to 250 ° C. The inner wall of the reaction chamber can automatically remove residual deposits on the inner wall of the MOCVD reaction chamber. The plasma of the cleaning gas does not cause damage to the inner wall of the MOCVD reaction chamber, and the cleaning takes a short time.

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the invention.

Specific details are set forth in the following description in order to provide a thorough understanding of the invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar promotion without departing from the scope of the present invention. Therefore, the invention is not limited by the specific embodiments disclosed herein.

1 is a schematic flow chart of a cleaning method of an MOCVD device according to an embodiment of the present invention. Specifically, the method includes: Step S101: After forming a thin film on a substrate by using an MOCVD device, removing a substrate on the pedestal in the MOCVD device a reaction chamber; in step S102, a cleaning gas is introduced into the reaction chamber of the MOCVD device; in step S103, the cleaning gas is plasmatized by a plasma processing device; and in step S104, the temperature of the inner wall of the reaction chamber is raised to From 50 ° C to 250 ° C, the inner wall of the reaction chamber is cleaned with a plasma of a cleaning gas at the temperature.

Specifically, please refer to FIG. 2 , which is a schematic structural diagram of an MOCVD apparatus according to an embodiment of the present invention. The MOCVD apparatus specifically includes a reaction chamber 110 including a sidewall 111, a bottom portion 112 and a top portion 113; one or more susceptors 115 located inside the reaction chamber 110, the susceptor 115 for carrying a substrate to be processed (not shown); an exhaust port 141 located at a side wall or a bottom of the reaction chamber 110 and connected to the air pump 140, and the exhaust gas 141 is used to discharge excess gas and exfoliated residual deposits into the reaction chamber 110; a gas shower head 120 located at the top 113 of the reaction chamber, the gas shower head 120 is configured to transport a reaction gas or a cleaning gas to the reaction chamber 110, and the gas shower head 120 further has a shower head cooling Device 125, in utilizing the During the deposition of the film by the MOCVD apparatus, cold water is introduced into the shower head cooling device 125 in a loop to reduce the temperature of the gas shower head 120, thereby avoiding excessive temperature damage to the gas shower head 120. And the lower temperature is also disadvantageous for the formation of residual deposits on the surface of the gas shower head 120, which can reduce the removal time of the residual deposits on the surface of the gas shower head 120; the plasma processing device is used to form the reaction gas into a plasma . In the present embodiment, the plasma processing apparatus includes a radio frequency supply source 131 and a radio frequency matching unit 132, and the radio frequency supply source 131 is connected to the susceptor 115 through the radio frequency matching unit 132.

After step S101 is performed, after the film is formed on the substrate by the MOCVD device, the substrate on the susceptor in the MOCVD device is removed from the reaction chamber.

In order to prevent residual deposits bombarded from the top of the reaction chamber during the cleaning process from falling onto the substrate, after forming a film on the substrate by the MOCVD device, the susceptor in the MOCVD device is introduced before the cleaning gas is introduced. The upper substrate is removed from the reaction chamber.

Step S102 is performed to introduce a cleaning gas into the reaction chamber of the MOCVD device.

Since the MOCVD apparatus is mainly used for depositing a compound forming a Group III element and a Group V element, a compound film forming a Group III element and a Group V element is deposited on the substrate, and also on the side wall of the reaction chamber of the MOCVD apparatus. 111, the bottom 112, and the top of the gas showerhead 120 form a residual deposit of a Group III element and a Group V element compound. Since the residual deposits on the surface of the gas shower head 120 at the top side of the reaction chamber and the top of the gas shower head 120 may peel off during the deposition of the film, the residual deposits of the peeling fall on the substrate to be processed may cause defects in the deposited film. Therefore, the plasma of the corresponding cleaning gas is required to react with the Group III element and the Group V element compound, thereby removing the residual deposit.

The cleaning gas includes at least a first cleaning gas for chemical cleaning, and may further include a second cleaning gas for physical cleaning. The first cleaning gas includes at least Cl element, which is one or a combination of Cl ₂ and HCl, and the plasma of the Cl element is relatively easy to be combined with a compound of a Group III element and a Group V element (for example, gallium nitride). The reaction occurs, and the plasma of the cleaning gas having the Cl element can remove the Group III element and the Group V element compound relatively quickly. The second cleaning gas is one or a combination of Ar and N ₂ , and the Ar and N in the plasma state have strong kinetic energy, and the inner wall of the reaction chamber is bombarded so as to be located inside the reaction chamber. Residual deposits on the wall surface are peeled off and exit the reaction chamber through the vent.

In this embodiment, the cleaning gas is a mixed gas of Cl ₂ and Ar, the flow rate of the mixed gas is 0.5 to 2.0 slm, and the pressure in the reaction chamber is 0.5 Torr. The mixed gas forms a plasma in a subsequent process including a plasma of a state of Cl and a plasma of Ar. Since the plasma of the plasma has a strong chemical energy, it can react with the Group III element and the Group V element compound. And the plasma state Ar has a strong kinetic energy, and by bombarding the inner wall of the reaction chamber, residual deposits on the inner wall surface of the reaction chamber are peeled off, and the reaction chamber is discharged through the exhaust port.

Step S103 is performed to plasmaize the cleaning gas by a plasma processing apparatus.

The plasma processing apparatus includes an inductively coupled plasma processing apparatus or a capacitively coupled plasma processing apparatus.

In this embodiment, the plasma processing apparatus is a capacitively coupled plasma processing apparatus. Referring to FIG. 2, the capacitively coupled plasma processing apparatus includes a radio frequency supply source 131 and a radio frequency matching unit 132. The radio frequency supply source 131 is connected to the susceptor 115 through the radio frequency matching unit 132. When a radio frequency signal generated by the RF power source 131 is applied to the susceptor 115, a high frequency electric field is formed in the reaction chamber 110, and the high frequency electric field causes the cleaning gas in the reaction chamber 110 to form a plasma, utilizing The plasma cleans residual deposits on the inner wall of the reaction chamber.

In another embodiment, referring to FIG. 3, the capacitively coupled plasma processing apparatus includes a radio frequency supply source 231 and a radio frequency matcher 232, and the radio frequency supply source 231 passes the The RF matcher 232 is coupled to the gas showerhead 120. When a radio frequency signal generated by the RF supply source 231 is applied to the gas showerhead 120, a high frequency electric field is formed in the reaction chamber 110, and the high frequency electric field causes a cleaning gas in the reaction chamber 110 to form a plasma. The plasma is used to clean residual deposits on the inner wall of the reaction chamber.

In another embodiment, the plasma processing apparatus is an inductively coupled plasma processing apparatus. Referring to FIG. 4, the inductively coupled plasma processing apparatus includes an inductor 350, a radio frequency supply source 331 and a radio frequency matcher 332 located outside the reaction chamber sidewall 111, and the radio frequency supply source 331 passes through the radio frequency matcher 332. It is connected to the inductor coil 350. When a radio frequency signal generated by the RF supply source 331 is applied to the inductor 350, a high-frequency electric field is formed in the reaction chamber 110, and the high-frequency electric field causes the cleaning gas in the reaction chamber 110 to form a plasma, utilizing The plasma cleans residual deposits on the inner wall of the reaction chamber.

Step S104 is performed to raise the temperature of the inner wall of the reaction chamber to 50 ° C to 250 ° C, and the inner wall of the reaction chamber is cleaned by the plasma of the cleaning gas at the temperature.

The inventors have found through research that, referring to FIG. 5, a comparison chart of the results of cleaning the residual deposits with plasma of the cleaning gas at different temperatures. Residual deposits on the inner wall of the reaction chamber are removed by the plasma of the cleaning gas, and as the temperature of the inner wall of the reaction chamber increases, the plasma cleans the residual deposits on the inner wall of the reaction chamber. accelerate. However, since the material of the reaction chamber inner wall and the gas shower head of the MOCVD apparatus is aluminum alloy or stainless steel, the aluminum alloy or stainless steel material does not react with the plasma state Cl at a lower temperature, but when When the temperature of the inner wall of the reaction chamber is higher than 250 ° C, the plasma state of Cl easily reacts with the metal material on the inner wall of the reaction chamber and the surface of the gas shower head, so that the inner wall of the reaction chamber of the MOCVD apparatus and the gas shower head are generated. damage. Therefore, in the practice of the present invention, the inner wall of the reaction chamber is cleaned by a plasma of a cleaning gas at a temperature of 50 ° C to 250 ° C, and the residual deposits on the inner wall of the reaction chamber can be automatically cleaned without Damage to the inner wall of the reaction chamber. Among them, when the temperature is between 200 ° C and 250 ° C, the anti-fast cleaning can be performed relatively quickly. Residual deposits on the inner wall of the chamber should not cause damage to the inner wall of the reaction chamber.

When a high-frequency electric field is formed in the reaction chamber 110, the high-frequency electric field generates heat during plasmaization of the cleaning gas, and the inner wall of the reaction chamber 110 is heated by the heat to make the inner wall of the reaction chamber 110 The surface temperature rises to 50 ° C ~ 250 ° C. In order to enable the heat generated by the cleaning gas plasmaization process to be greater than or equal to the heat dissipated by the MOCVD device, the power of the radio frequency supply source of the plasma processing apparatus is greater than or equal to 1000 W. In this embodiment, The power of the RF supply is 2000W.

In the prior art, the gas shower head in the MOCVD apparatus has a shower head cooling device, and the shower head cooling device is provided with continuous circulating cold water. Since the formation of the film by the MOCVD process requires a high temperature of nearly 1000 ° C, the continuous circulation of cold water can effectively reduce the temperature of the gas shower head, avoid excessive temperature damage to the gas shower head, and lower temperature. It is also not conducive to the formation of residual deposits on the surface of the gas shower head, and the residual deposits which form the surface of the gas shower head are in powder form. The powdery residual deposits are easy to clean and can reduce the residual of the surface of the gas shower head. Sediment removal time.

In this embodiment, during the cleaning process of the reaction chamber of the MOCVD device, liquid such as cooling water is not introduced into the shower head cooling device 125, so that the shower head cooling device 125 is vacant, and the cleaning gas plasma is The heat generated by the body is simultaneously heated to the inner wall of the reaction chamber 110 and the gas shower head 120, so that the temperature of the inner wall surface of the reaction chamber 110 and the surface of the gas shower head 120 are simultaneously raised to 50 ° C to 250 ° C. The residual deposits on the inner wall surface of the 110, the surface of the gas showerhead 120 can be removed at the same rate.

In another embodiment, residual deposits on the surface of the gas showerhead 120 above the substrate are most likely to fall on the substrate to be processed compared to residual deposits on the surface of the reaction chamber sidewalls 111 and bottom 112, making the substrate susceptible to substrate The surface-formed film produces defects, so that during the cleaning of the MOCVD reaction chamber, residual deposits on the surface of the gas showerhead 120 need to be removed as much as possible.

During the cleaning process of the reaction chamber of the MOCVD apparatus, a constant-circulating high-temperature liquid is introduced into the shower head cooling device 125, so that the temperature of the surface of the gas shower head 120 rises to 50 ° C to 250 ° C. The material of the high temperature liquid is eucalyptus oil, heat transfer oil, molten salt or water.

The heat generated by the high temperature liquid and the heat generated by the plasma of the cleaning gas act on the gas shower head 120 for increasing the temperature of the gas shower head such that the temperature of the gas shower head 120 Above the temperature of the reaction chamber sidewall 111 and the bottom portion 112, the rate of residual deposits on the surface of the gas showerhead 120 is cleaned by the plasma of the cleaning gas, which is advantageous for the surface of the gas showerhead 120. The residual deposits are removed as much as possible. In addition, the heat generated by the high temperature liquid and the heat generated by the plasma of the cleaning gas act together on the gas shower head, and the power of the radio frequency signal generated by the radio frequency supply source can be small, thereby saving the reaction chamber of the MOCVD device. The electrical energy consumed during the cleaning process.

In summary, the cleaning method of the MOCVD apparatus according to the embodiment of the present invention uses the heat generated by the plasma cleaning gas to raise the temperature of the inner wall of the reaction chamber to 50 ° C to 250 ° C, and clean the plasma with the cleaning gas at the temperature. The inner wall of the reaction chamber. As the temperature increases, the rate of removal of residual deposits on the inner wall of the reaction chamber by the plasma of the cleaning gas is also gradually increased, and the reaction chamber is cleaned by plasma using a cleaning gas at a temperature of 50 ° C to 250 ° C. The wall can automatically remove residual deposits from the inner wall of the MOCVD reaction chamber, the plasma of the cleaning gas does not cause damage to the inner wall of the MOCVD reaction chamber, and the cleaning takes a short time.

Further, during the cleaning process of the reaction chamber of the MOCVD apparatus, a constant circulating hot liquid is introduced into the shower head cooling device, so that the temperature of the surface of the gas shower head rises to 50 ° C to 250 ° C. The heat generated by the high temperature liquid and the heat generated by the plasma of the cleaning gas act on the gas shower head, and the power of the radio frequency signal generated by the radio frequency supply source can be small, thereby saving the cleaning process of the reaction chamber of the MOCVD device. The energy consumed in it.

The above description is only illustrative of the preferred embodiment of the present invention. Other improvements may be made in light of the above description, but such changes are still within the scope of the invention and the scope of the invention as defined below.

Claims (11)

A cleaning method for an MOCVD apparatus, comprising: introducing a cleaning gas into a reaction chamber of the MOCVD device; plasma-cleaning the cleaning gas by using a plasma processing device; and raising a temperature of the inner wall of the reaction chamber to 50 ° C to 250 ° C At this temperature, the inner wall of the reaction chamber is cleaned by the plasma of the cleaning gas. The cleaning method of the MOCVD apparatus according to claim 1, wherein the temperature of the inner wall of the reaction chamber is raised to 200 ° C to 250 ° C at which the inner wall of the reaction chamber is cleaned by plasma of the cleaning gas. The cleaning method of the MOCVD apparatus according to claim 1, wherein the MOCVD apparatus has a gas shower head at the top of the reaction chamber, and the gas shower head has a shower head cooling device therein. The cleaning method of the MOCVD apparatus according to claim 1, wherein the liquid in the shower head is not introduced into the shower head cooling device while the inner wall of the reaction chamber is cleaned by the plasma of the cleaning gas. The cleaning method of the MOCVD apparatus according to claim 1, wherein while the inner wall of the reaction chamber is cleaned by the plasma of the cleaning gas, the high temperature liquid is introduced into the shower head cooling device, so that the surface of the shower head is The temperature rises to 50 ° C ~ 250 ° C. The cleaning method of the MOCVD apparatus according to claim 5, wherein the material of the high temperature liquid is eucalyptus oil, heat transfer oil, molten salt or water. The cleaning method of the MOCVD apparatus according to claim 1, wherein the plasma processing apparatus comprises an inductively coupled plasma processing apparatus and a capacitively coupled plasma processing apparatus. A cleaning method of the MOCVD apparatus according to claim 1, wherein the plasma The power of the body treatment device is greater than or equal to 1000 W, and the inner wall of the reaction chamber is heated by thermal energy generated by the plasma. The cleaning method of the MOCVD apparatus according to claim 1, wherein the cleaning gas includes at least a first cleaning gas for chemical cleaning, the first cleaning gas including at least a Cl element. The cleaning method of the MOCVD apparatus according to claim 9, wherein the first cleaning gas is one of or a combination of Cl ₂ and HCl. The cleaning method of the MOCVD apparatus according to claim 9, wherein the cleaning gas further comprises a second cleaning gas for physical cleaning, the second cleaning gas being one or a combination of two of Ar, N ₂ .