Device and method for quickly restoring ICP cavity working environment

Abstract

The present invention belongs to the field of semiconductor technology, and discloses a device and method for quickly restoring the operating environment of an ICP cavity. The device includes: a carrier stage, including a circumferential surface and an upper surface, wherein the upper surface of the carrier stage is provided with fine micropores, and the interior of the carrier stage is hollow; a cooling circulation system, arranged inside the carrier stage for delivering coolant to the carrier stage; a gas heat transfer conduit, arranged inside the carrier stage for temperature conduction between the carrier stage and the wafer carrier; an exhaust pipe, arranged directly below the carrier stage and connected to the ICP cavity, wherein the exhaust port of the exhaust pipe is located on the wall of the ICP cavity, and the plane where the exhaust port is located is the exhaust port plane; a thimble, passing through the carrier stage and exposed on the upper surface of the carrier stage for lifting the wafer carrier; and a thimble cylinder, located below the carrier stage and above the exhaust port plane for driving the thimble to move up and down. By arranging the exhaust port directly below the carrier stage, the present invention shortens the distance between the air outlet and the exhaust port, thereby improving the etching efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor ICP (Inductively Coupled Plasma), and relates to a device and method for quickly restoring the working environment of an ICP cavity. Background Art

[0002] Etching in semiconductor manufacturing processes is divided into wet etching and dry etching. In the early days, wet etching was commonly used. However, due to its limitations in aspects such as line width control and etching directionality, dry etching has been mostly adopted for processes after 3μm; wet etching is only used for the removal of certain special material layers and the cleaning of residues. Dry etching refers to the process of using a gaseous chemical etchant to react with the material on the wafer, etching away the part of the material to be removed and forming a volatile reaction product, and then evacuating it from the reaction chamber; the etchant is usually directly or indirectly generated from the plasma of the etching gas, so dry etching is also called plasma etching.

[0003] Inductively Coupled Plasma (ICP) is an important technology in the semiconductor industry, mainly used for removing photoresist in wafer manufacturing and for etching. This technology is developed according to the process requirements of the semiconductor industry. By passing a high-frequency current through a spiral coil to generate an inductively coupled plasma, the etching and processing of materials can be achieved. ICP technology has a wide range of applications in fields such as integrated optics, optoelectronics, microelectromechanical systems (MEMS), and photonic crystals, and is a key step in fabricating many important devices, such as white light LEDs, semiconductor lasers, and detectors.

[0004] In the maintenance of semiconductor ICP dry etching equipment, a dust-free cloth with ethanol, isopropyl alcohol, or pure water is usually used to wipe the working cavity. Since the cavity needs to be opened for treatment, the inner cavity will come into contact with the atmosphere, destroying its vacuum state. And after being wiped with the above solvents, the humidity in the cavity rises, resulting in the need to perform multiple Dummy Wafers (also known as Test Wafers, with the Chinese name being test wafer / fake wafer) for subsequent cavity closing in order to restore the optimal working environment of the cavity. Usually, it takes 4 - 12 hours and requires 2 - 4 Dummy Wafers. In view of this, there is an urgent need to provide a device and method for quickly restoring the working environment of an ICP cavity. Summary of the Invention

[0005] Based on this, the present invention provides a device and method for quickly restoring the working environment of an ICP cavity, solving the problem of the too long recovery time of the working environment of the cavity after maintenance.

[0006] The technical solution of the present invention is as follows:

[0007] A device for quickly restoring the working environment of an ICP cavity provided by the present invention includes:

[0008] The stage includes a circumferential surface and an upper surface. Tiny holes are provided on the upper surface of the stage, and the interior of the stage is hollow.

[0009] The cooling circulation system is arranged inside the stage and is used to convey coolant to the stage.

[0010] The gas heat transfer pipe is arranged inside the stage and is used for temperature conduction between the stage and the wafer carrier.

[0011] The exhaust pipe is arranged directly below the stage and is connected to the ICP cavity. The exhaust port of the exhaust pipe is located on the wall of the ICP cavity, and the plane where the exhaust port is located is the exhaust port plane.

[0012] The ejector pin passes through the stage and is exposed on the upper surface of the stage, and is used to lift the wafer carrier.

[0013] The ejector pin cylinder is located below the stage and above the exhaust port plane, and is used to drive the ejector pin to move up and down.

[0014] Further, the cooling circulation system includes a cooler inlet pipe and a cooler outlet pipe. The cooler inlet pipe is used to input coolant into the stage, and the cooler outlet pipe is used to output coolant from the stage.

[0015] Preferably, the cooler inlet pipe and the cooler outlet pipe are made of metal.

[0016] Preferably, the gas heat transfer pipe is a helium pipe.

[0017] Further, the device further includes:

[0018] The ceramic protective cover is located below the stage and above the exhaust port plane, and is fixedly connected to the stage and the exhaust port plane respectively; it is used to protect the cooling circulation system and the gas heat transfer pipe.

[0019] Further, the device further includes:

[0020] The filter is installed at the front end of the exhaust port of the exhaust pipe and is used to filter process waste.

[0021] Further, the filter is fixed to the exhaust pipe by a clamp and is detachably connected to the exhaust pipe.

[0022] Preferably, the interior of the filter is composed of a 316 stainless steel panel with round holes having a diameter of 5 mm.

[0023] Further, the device further includes:

[0024] The ceramic partition net is installed on the periphery of the circumferential surface of the stage and is used to adsorb process waste.

[0025] The present invention also provides a method for quickly restoring the operating environment of an ICP cavity, including the following steps:

[0026] S1 Open the ICP cavity, remove the ceramic separator, wipe the connection between the ceramic separator and the ICP cavity with ethanol, then install a spare ceramic separator, and close the ICP cavity;

[0027] S2 Remove the filter, install a spare filter, and evacuate the ICP cavity;

[0028] S3 After evacuating the ICP cavity to the ultimate vacuum, use a manipulator to transfer a Dummy Wafer to the wafer stage;

[0029] S4 Introduce 150 ± 5 sccm of chlorine gas into the ICP cavity and flow the gas for 10 minutes;

[0030] S5 Without closing the chlorine gas, turn on the upper radio frequency and input a radio frequency power of 1500 W, and wait for 2 minutes;

[0031] S6 Turn off the upper radio frequency, close the chlorine gas, introduce 80 ± 2 sccm of boron trichloride into the ICP cavity, and flow the gas for 5 minutes;

[0032] S7 Without closing the boron trichloride, turn on the upper radio frequency and input a radio frequency power of 1200 W, and wait for 2 minutes;

[0033] S8 Turn off the upper radio frequency, close the boron trichloride, introduce 200 ± 5 sccm of oxygen gas and 100 ± 2 sccm of carbon tetrafluoride into the ICP cavity, and flow the gas for 2 minutes;

[0034] S9 Close the oxygen gas and carbon tetrafluoride, and at the same time turn on the chlorine gas and boron trichloride. Introduce 50 ± 1 sccm of each of chlorine gas and boron trichloride into the ICP cavity, turn on the upper radio frequency and input a radio frequency power of 800 W, turn on the lower radio frequency and input a radio frequency power of 300 W, and wait for 1 minute;

[0035] S10 Turn off the upper radio frequency, lower radio frequency and gas valve, and conduct a step test. If the standard is not met, repeat steps S3 - S9.

[0036] sccm is a unit of volume flow rate, and its full name is standard cubic centimeter per minute, which represents the volume of gas leaked per minute under standard conditions (temperature is 0 degrees Celsius, pressure is 1 atmosphere).

[0037] Advantages of the present invention:

[0038] (1) By setting the exhaust port directly below the stage, the distance between the gas outlet and the exhaust port is shortened, thereby improving the etching efficiency.

[0039] (2) By adding a ceramic protective cover, the cooler pipeline and the helium pipeline can be prevented from being corroded by the process gas.

[0040] (3) By adding a detachable filter at the air extraction port, the process residual compounds can be adsorbed in the filter, and it is convenient for disassembly and assembly.

[0041] (4) By adding a ceramic partition net around the circumferential surface of the stage, not only can the process residual compounds after the reaction be adsorbed once, but also the blockage of the filter at the air extraction port can be prevented from affecting the air extraction effect. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 Schematic diagram of the device for quickly restoring the operating environment of the ICP cavity provided by the embodiment of the present invention Figure 1 ;

[0044] Figure 2 Schematic diagram of the device for quickly restoring the operating environment of the ICP cavity provided by the embodiment of the present invention Figure 2 ;

[0045] Figure 3 Schematic diagram of the device for quickly restoring the operating environment of the ICP cavity provided by the embodiment of the present invention Figure 3 ;

[0046] Figure 4 Schematic diagram of the device for quickly restoring the operating environment of the ICP cavity provided by the embodiment of the present invention Figure 4 ;

[0047] Figure 5 Schematic diagram of the filter provided by the embodiment of the present invention;

[0048] Figure 6 Flowchart of the method for quickly restoring the operating environment of the ICP cavity provided by the embodiment of the present invention.

[0049] Description of the drawing numbers:

[0050] 1 - Stage, 2 - Cooler inlet pipe, 3 - Cooler outlet pipe, 4 - Helium pipeline, 5 - Exhaust pipe, 6 - Ejector pin, 7 - Ejector pin cylinder, 8 - Ceramic protective cover, 9 - Filter, 10 - Ceramic partition net, 11 - Circumferential surface of the stage, 12 - Upper surface of the stage, 13 - Air extraction port, 14 - Filter hole, 15 - Air extraction port surface Detailed implementation manners

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0052] As used herein, the mention of "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0053] In order to make the purpose, technical solutions, and advantages of this application more clear and understandable, the following further details this application in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0054] In this embodiment, the cooling circulation system includes a cooler inlet pipe and a cooler outlet pipe. The gas heat transfer pipe is selected as a helium pipe because the heat conduction performance of helium is better than that of other gases.

[0055] Please refer to Figures 1 - 4 , the device for quickly restoring the operating environment of the ICP cavity provided in this embodiment includes: a stage 1, a cooler inlet pipe 2, a cooler outlet pipe 3, a helium pipe 4, an exhaust pipe 5, a thimble 6, a thimble cylinder 7, a ceramic protective cover 8, a filter 9, and a ceramic partition 10.

[0056] The stage 1 includes a circumferential surface 11 and an upper surface 12. The upper surface 12 of the stage is provided with fine micropores for outputting helium, and the inside of the stage 1 is hollow.

[0057] The cooler inlet pipe 2 and the cooler outlet pipe 3 are collectively referred to as the Chiller pipeline, which is fixed inside the stage 1 through quick connectors. The cooler inlet pipe 2 is used to input coolant into the stage, and the cooler outlet pipe 3 is used to output coolant from the stage. The Chiller pipeline is made of metal.

[0058] The helium gas pipe 4 is connected from the gas holder to the inside of the carrier 1 through a ferrule joint, and is used for temperature conduction between the carrier and the wafer carrier; the helium gas pipe is the temperature conduction medium between the carrier and the wafer carrier.

[0059] The exhaust pipe 5 is arranged directly below the carrier 1 and is connected to the ICP cavity. The exhaust port 13 of the exhaust pipe is located on the wall of the ICP cavity, and the plane where the exhaust port 13 is located is the exhaust port surface 15. By arranging the exhaust port 13 directly below the carrier 1, the linear distance between the gas outlet and the exhaust port is shortened. After the process gas is ionized, the downward suction provided by the exhaust port 13 below will accelerate the reaction rate on the surface of the Wafer, thereby improving the etching efficiency.

[0060] The ejector pin 6 passes through the carrier 1 and is exposed on the upper surface 12 of the carrier, and is used to lift the wafer carrier.

[0061] The ejector pin cylinder 7 is fixed below the carrier 1 and above the exhaust port surface 15 through an Allen head bolt, and is used to drive the ejector pin 6 to move up and down. The ejector pin is fixed on the piston rod of the ejector pin cylinder through a bolt.

[0062] The upper and lower surfaces of the ceramic protective cover 8 are fixed below the carrier 1 and above the exhaust port surface 15 through Allen head full-thread bolts. By adding a ceramic protective cover, the cooler pipeline and the helium gas pipe are prevented from being corroded by the process gas.

[0063] The filter 9 is installed at the front end of the exhaust port of the exhaust pipe 5 through a clamp and is detachably connected to the exhaust pipe 5. By adding a detachable filter at the exhaust port, the process residual compounds can be adsorbed in the filter.

[0064] As Figure 5 shown, the filter in this embodiment is a porous filter, and its interior is composed of a round hole stainless steel 316 panel with a diameter of 5 mm.

[0065] The ceramic separator 10 is installed outside the circumferential surface 11 of the carrier and is used to adsorb process waste. By adding the ceramic separator 10 outside the circumferential surface 11 of the carrier, not only can the process residual compounds after the reaction be adsorbed once, but also the blockage of the filter at the exhaust port affecting the exhaust effect can be prevented.

[0066] As Figure 6 shown, the method flow for quickly restoring the operating environment of the ICP cavity provided by the embodiment of the present invention includes:

[0067] S1 Open the ICP cavity, remove the ceramic separator, wipe the connection between the ceramic separator and the ICP cavity with ethanol, then install the spare ceramic separator, and close the ICP cavity;

[0068] S2 Remove the filter, install the spare filter, and evacuate the ICP cavity;

[0069] After the ICP cavity is pumped to an ultimate vacuum, use a manipulator to transfer a tray of Dummy Wafer to the wafer stage.

[0070] S4 Introduce 150 ± 5 sccm of chlorine gas into the ICP cavity and flow the gas for 10 minutes.

[0071] S5 Without closing the chlorine gas, turn on the upper radio frequency and input a radio frequency power of 1500 W, and wait for 2 minutes.

[0072] S6 Turn off the upper radio frequency and the chlorine gas, introduce 80 ± 2 sccm of boron trichloride into the ICP cavity, and flow the gas for 5 minutes.

[0073] S7 Without closing the boron trichloride, turn on the upper radio frequency and input a radio frequency power of 1200 W, and wait for 2 minutes.

[0074] S8 Turn off the upper radio frequency and the boron trichloride, introduce 200 ± 5 sccm of oxygen and 100 ± 2 sccm of carbon tetrafluoride into the ICP cavity, and flow the gas for 2 minutes.

[0075] S9 Turn off the oxygen and carbon tetrafluoride, and at the same time turn on the chlorine gas and boron trichloride. Introduce 50 ± 1 sccm of each of chlorine gas and boron trichloride into the ICP cavity, turn on the upper radio frequency and input a radio frequency power of 800 W, turn on the lower radio frequency and input a radio frequency power of 300 W, and wait for 1 minute.

[0076] S10 Turn off the upper radio frequency, the lower radio frequency and the gas valve, and perform a step test. If the standard is not met, repeat steps S3 - S9.

[0077] The present invention adopts an alternating gas flow mode of chlorine gas and boron trichloride to make the inner cavity environment tend to be stable, adopts a mixed gas flow mode of oxygen and carbon tetrafluoride to clean the compound on the surface layer of the inner cavity, and adopts a mixed ionization mode of chlorine gas and boron trichloride to make the compound on the inner cavity wall flat and increase its viscosity, making it not easy to fall off.

[0078] The above are only the embodiments of the present invention. It should be noted here that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, improvements can still be made, but these all fall within the protection scope of the present invention.

Claims

1. A device for quickly restoring the operating environment of an ICP cavity, characterized in that, Comprising: A stage, including a circumferential surface and an upper surface, with fine micropores provided on the upper surface of the stage, and the interior of the stage is hollow; A cooling circulation system, arranged inside the stage, for conveying coolant to the stage; A gas heat transfer pipe, arranged inside the stage, for temperature conduction between the stage and the wafer carrier; An exhaust pipe, arranged directly below the stage and connected to the ICP cavity, with the exhaust port of the exhaust pipe located on the wall of the ICP cavity, and the plane where the exhaust port is located is the exhaust port plane; A thimble, passing through the stage and exposed on the upper surface of the stage, for lifting the wafer carrier; A thimble cylinder, located below the stage and above the exhaust port plane, for driving the thimble to move up and down; A ceramic partition net, installed around the circumferential surface of the stage, for adsorbing process waste.

2. The device for quickly restoring the operating environment of the ICP cavity according to claim 1, characterized in that, The cooling circulation system includes a cooler inlet pipe and a cooler outlet pipe. The cooler inlet pipe is used to input coolant into the stage, and the cooler outlet pipe is used to output coolant from the stage.

3. The device for quickly restoring the working environment of the ICP cavity according to claim 1, wherein, The gas heat transfer pipe is a helium pipe.

4. The device for quickly restoring the operating environment of the ICP cavity according to claim 1, wherein, The device further includes: A ceramic protective cover, located below the stage and above the exhaust port plane, and fixedly connected to the stage and the exhaust port plane respectively; for protecting the cooling circulation system and the gas heat transfer pipe.

5. The device for quickly restoring the operating environment of the ICP cavity according to claim 1, wherein The device further includes: A filter, installed at the front end of the exhaust port of the exhaust pipe, for filtering process waste.

6. The device for quickly restoring the ICP cavity operating environment according to claim 5, wherein, The filter is fixed to the exhaust pipe by a clamp and is detachably connected to the exhaust pipe.

7. The device for quickly restoring the ICP cavity working environment according to claim 5, characterized in that, The interior of the filter is composed of a round hole stainless steel 316 panel with a diameter of 5 mm.

8. The device for quickly restoring the ICP cavity working environment according to claim 2, characterized in that, The cooler inlet pipe and the cooler outlet pipe are made of metal.

9. A method for quickly restoring the operating environment of an ICP cavity, characterized in that, Including the following steps: S1 Open the ICP cavity, remove the ceramic partition net, wipe the connection between the ceramic partition net and the ICP cavity with ethanol, then install the spare ceramic partition net, and close the ICP cavity; S2 Remove the filter, install the spare filter, and evacuate the ICP cavity; S3 After the ICP cavity is evacuated to the ultimate vacuum, use a manipulator to transfer a Dummy Wafer to the stage; S4 Introduce 150 ± 5 sccm of chlorine gas into the ICP cavity and flow the gas for 10 min; S5 Without closing the chlorine gas, turn on the upper radio frequency, input 1500 W of radio frequency power, and wait for 2 min; S6 Turn off the upper radio frequency, turn off the chlorine gas, introduce 80 ± 2 sccm of boron trichloride into the ICP cavity, and flow the gas for 5 min; S7 Without closing the boron trichloride, turn on the upper radio frequency, input 1200 W of radio frequency power, and wait for 2 min; S8 Turn off the upper radio frequency, turn off the boron trichloride, introduce 200 ± 5 sccm of oxygen and 100 ± 2 sccm of carbon tetrafluoride into the ICP cavity, and flow the gas for 2 min; S9 Turn off the oxygen and carbon tetrafluoride, and at the same time turn on the chlorine gas and boron trichloride. Introduce 50 ± 1 sccm of each of chlorine gas and boron trichloride into the ICP cavity, turn on the upper radio frequency, input 800 W of radio frequency power, turn on the lower radio frequency, input 300 W of radio frequency power, and wait for 1 min; S10 Turn off the upper radio frequency, lower radio frequency and gas valve, and conduct a step test. If the standard is not met, repeat steps S3 - S9.

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