阅读说明：本技术 陶瓷件的加工方法 (Method for processing ceramic piece ) 是由 曹泽京 符雅丽 于 2021-08-30 设计创作，主要内容包括：本发明提供一种陶瓷件的加工方法,用于对经过机械加工的陶瓷件进行表面处理,其包括以下步骤：对所述陶瓷件进行等离子体刻蚀,以去除所述陶瓷件的待处理表面上的损伤和颗粒；对进行等离子体刻蚀后的所述陶瓷件的待处理表面进行清洗,以去除所述陶瓷件进行等离子体刻蚀的步骤中在所述陶瓷件的待处理表面上产生的固态生成物。本发明实施例提出供的陶瓷件的加工方法,能够有效去除陶瓷件表面的颗粒和损伤。(The invention provides a processing method of a ceramic piece, which is used for carrying out surface treatment on the ceramic piece after mechanical processing and comprises the following steps: carrying out plasma etching on the ceramic piece to remove damage and particles on the surface to be processed of the ceramic piece; and cleaning the surface to be processed of the ceramic piece after the plasma etching is carried out so as to remove solid products generated on the surface to be processed of the ceramic piece in the step of carrying out the plasma etching on the ceramic piece. The processing method of the ceramic part provided by the embodiment of the invention can effectively remove particles and damage on the surface of the ceramic part.)

1. A method for processing a ceramic member, which is used for surface treatment of a ceramic member subjected to mechanical processing, comprising the steps of:

carrying out plasma etching on the ceramic piece to remove damage and particles on the surface to be processed of the ceramic piece;

and cleaning the surface to be processed of the ceramic piece after the plasma etching is carried out so as to remove solid products generated on the surface to be processed of the ceramic piece in the step of carrying out the plasma etching on the ceramic piece.

2. The method of claim 1, wherein the step of plasma etching the ceramic part comprises:

placing the ceramic piece in an etching chamber;

introducing process gas into the etching chamber to enable the internal pressure of the etching chamber to reach a preset pressure value;

starting an upper radio frequency power supply to excite the process gas into plasma;

controlling the internal temperature of the etching chamber to be kept at a preset etching temperature, adjusting the output power of the upper radio frequency power supply to a first preset power value, and adjusting the output power of the lower radio frequency power supply to a second preset power value, so that the plasma bombards the surface to be processed of the ceramic piece under the action of gravity and chemically reacts with the material of the surface to be processed of the ceramic piece and the particles to remove the damage and the particles on the surface to be processed of the ceramic piece.

3. The method according to claim 2, wherein the process gas comprises a main etching gas and an auxiliary etching gas, wherein the main etching gas is used for chemically reacting with the surface material to be processed of the ceramic piece and the particles after being excited into plasma and generating the product;

the auxiliary etching gas is used to promote the chemical reaction after being excited into plasma.

4. A method of manufacturing a ceramic part according to claim 3, wherein the ceramic part is made of alumina; the main etching gas comprises chlorine; the auxiliary etching gas comprises an inert gas.

5. The method according to claim 3, wherein a ratio of a gas inflow rate of the main etching gas to that of the auxiliary etching gas is 1:1 or less and 1:3.5 or more.

6. The method of claim 5, wherein the step of introducing a process gas into the etching chamber comprises:

introducing the main etching gas into the etching chamber at a first gas inflow rate, and introducing the auxiliary etching gas into the etching chamber at a second gas inflow rate; wherein the content of the first and second substances,

the first intake air flow value is more than or equal to 150sccm and less than or equal to 300 sccm; the second intake air flow value is greater than or equal to 400sccm and less than or equal to 650 sccm.

7. The method for processing a ceramic part according to claim 2, wherein the preset pressure value is greater than or equal to 600mTorr and less than or equal to 900 mTorr;

the first preset power value is more than or equal to 1800W and less than or equal to 2200W;

the second preset power value is equal to 0W;

the preset etching temperature is more than or equal to 60 ℃ and less than or equal to 70 ℃.

8. The method of claim 1, further comprising, after said step of machining said ceramic part and before said step of plasma etching said ceramic part:

and baking the ceramic piece to dry the surface to be processed of the ceramic piece.

9. The method of claim 1, wherein the step of cleaning the surface of the ceramic part to be treated comprises:

soaking the ceramic piece in a cleaning solution to remove the solid product;

and removing the residual cleaning solution on the surface to be treated of the ceramic piece.

10. The method of claim 1, further comprising, after the step of cleaning the surface of the ceramic part to be treated:

and standing the ceramic piece until the stress in the surface to be processed of the ceramic piece is completely released.

11. A method of processing a ceramic part according to any one of claims 1 to 10, wherein the ceramic part comprises a ceramic layer of an electrostatic chuck and a ceramic process kit for a semiconductor device.

Technical Field

The invention relates to the field of semiconductor manufacturing, in particular to a processing method of a ceramic piece.

Background

Because the ceramic has the characteristics of hard quality, wear resistance, good oxidation resistance, high strength and the like, the ceramic is widely applied to the field of semiconductor etching. The alumina ceramic is prepared from alumina (Al)₂O₃) The ceramic material as the main body is the most stable substance in oxide, and has the advantages of high temperature resistance, corrosion resistance, wear resistance, high mechanical strength, high hardness, high electrical insulation, low dielectric loss and the like, so that the alumina ceramic material is increasingly applied to semiconductor equipment. FIG. 1 shows the surface particle attachment of a prior art machined ceramic partIn this case, it can be seen that many fine particles (white dots shown in fig. 1) are attached to the surface of the ceramic part after the ceramic part is machined, and the diameter of the particles attached to the surface of the ceramic part can reach 0.2um to 1 um; fig. 2 shows a surface damage state of a conventional ceramic member subjected to machining, and it can be seen that a plurality of surface damages, such as pits, scratches, and the like, are also caused on the surface of the ceramic member during the machining, and the thickness of a surface damage layer having the plurality of surface damages may be in a range of 10um to 30 um.

In order to eliminate particles and damages on the surface of the ceramic part, the conventional pure water cleaning or ultrasonic pure water cleaning is usually adopted in the prior art, but actually, the cleaning method cannot effectively remove the particles and damages on the surface of the ceramic part. If the ceramic part with particles and damage on the surface is applied to a semiconductor etching machine, gas or liquid medicine used for an etching process is polluted by the particles separated from the surface of the ceramic part, and the yield of processed wafers is further influenced. Therefore, a processing method capable of effectively removing particles and damages on the surface of the ceramic part is provided, which is a technical problem to be solved in the field.

Disclosure of Invention

The invention aims to at least solve one of the technical problems in the prior art and provides a processing method capable of effectively removing particles and damages on the surface of a ceramic piece.

In order to achieve the object of the present invention, a method for processing a ceramic part is provided, which is used for performing surface treatment on the ceramic part after mechanical processing, and is characterized by comprising the following steps:

carrying out plasma etching on the ceramic piece to remove damage and particles on the surface to be processed of the ceramic piece;

and cleaning the surface to be processed of the ceramic piece after the plasma etching is carried out so as to remove solid products generated on the surface to be processed of the ceramic piece in the step of carrying out the plasma etching on the ceramic piece.

Optionally, the step of performing plasma etching on the ceramic piece includes:

placing the ceramic piece in an etching chamber;

introducing process gas into the etching chamber to enable the internal pressure of the etching chamber to reach a preset pressure value;

starting an upper radio frequency power supply to excite the process gas into plasma;

controlling the internal temperature of the etching chamber to be kept at a preset etching temperature, adjusting the output power of the upper radio frequency power supply to a first preset power value, and adjusting the output power of the lower radio frequency power supply to a second preset power value, so that the plasma bombards the surface to be processed of the ceramic piece under the action of gravity and chemically reacts with the material of the surface to be processed of the ceramic piece and the particles to remove the damage and the particles on the surface to be processed of the ceramic piece.

Optionally, the process gas includes a main etching gas and an auxiliary etching gas, wherein the main etching gas is used for generating a chemical reaction with the surface material to be processed of the ceramic piece and the particles after being excited into plasma, and generating the product;

the auxiliary etching gas is used to promote the chemical reaction after being excited into plasma.

Optionally, the ceramic piece is made of alumina; the main etching gas comprises chlorine; the auxiliary etching gas comprises an inert gas.

Optionally, the gas inflow ratio of the main etching gas to the auxiliary etching gas is less than or equal to 1:1 and greater than or equal to 1: 3.5.

Optionally, the step of introducing the process gas into the etching chamber includes:

introducing the main etching gas into the etching chamber at a first gas inflow rate, and introducing the auxiliary etching gas into the etching chamber at a second gas inflow rate; wherein the content of the first and second substances,

the first intake air flow value is more than or equal to 150sccm and less than or equal to 300 sccm; the second intake air flow value is greater than or equal to 400sccm and less than or equal to 650 sccm.

Optionally, the preset pressure value is greater than or equal to 600mTorr and less than or equal to 900 mTorr;

the first preset power value is more than or equal to 1800W and less than or equal to 2200W;

the second preset power value is equal to 0W;

the preset etching temperature is more than or equal to 60 ℃ and less than or equal to 70 ℃.

Optionally, after the step of machining the ceramic piece and before the step of plasma etching the ceramic piece, the method further includes:

and baking the ceramic piece to dry the surface to be processed of the ceramic piece.

Optionally, the step of cleaning the surface to be treated of the ceramic piece includes:

soaking the ceramic piece in a cleaning solution to remove the solid product;

and removing the residual cleaning solution on the surface to be treated of the ceramic piece.

Optionally, after the step of cleaning the surface to be treated of the ceramic piece, the method further includes:

and standing the ceramic piece until the stress in the surface to be processed of the ceramic piece is completely released.

Optionally, the ceramic part described in the above embodiments includes a ceramic layer for a ceramic process kit and an electrostatic chuck of a semiconductor device.

The invention has the following beneficial effects:

according to the processing method of the ceramic part, the surface material of the ceramic part is removed by utilizing the plasma etching process, so that the damage and particles on the surface of the ceramic part can be effectively removed; and because the precision of the plasma etching process is higher, the surface material of the ceramic part is removed by using the plasma etching process, and the removal amount can be accurately controlled by controlling the process conditions of the etching process, so that the surface damage of the ceramic part can be effectively removed, and the additional damage on the surface of the ceramic part can be avoided.

Drawings

FIG. 1 is an electron microscope image showing the particle adhesion on the surface of a conventional ceramic part after machining;

FIG. 2 is an electron microscope image of the surface damage condition of a conventional ceramic part after machining;

FIG. 3 is a flow chart of a method for processing a ceramic part according to an embodiment of the present invention;

FIG. 4 is a flowchart of the steps for plasma etching a ceramic part according to an embodiment of the present invention;

FIG. 5 is a comparison of the particle adhesion before and after processing the ceramic part by the processing method according to the embodiment of the present invention;

fig. 6 is a comparison graph of surface damage before and after the ceramic member is processed by the processing method according to the embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following describes the processing method of the ceramic part provided by the present invention in detail with reference to the accompanying drawings.

The embodiment provides a processing method of a ceramic piece, which is used for carrying out surface treatment on the ceramic piece after mechanical processing so as to remove damage and particles on the surface of the ceramic piece. After the ceramic green body is sintered and cured, the resulting ceramic part is typically of a relatively high hardness and is commonly used as a component of semiconductor processing equipment, and in some embodiments, the ceramic part comprises a ceramic layer of an electrostatic chuck and a ceramic process kit for semiconductor equipment. In order to make the size, shape and surface roughness of the ceramic piece meet the desired conditions for practical application, after sintering the ceramic green body into the ceramic piece, the ceramic piece needs to be subjected to various machining processes such as cutting, grinding and punching; however, since the hardness of the ceramic member is high, a cutter or an abrasive having high hardness must be used in the subsequent machining process, which tends to leave damage on the surface of the ceramic member, and fine particles generated during cutting and grinding adhere to the surface of the ceramic member and are difficult to remove.

In order to solve the above technical problem, as shown in fig. 3, the processing method of the ceramic piece provided by this embodiment includes the following steps:

step S1: carrying out plasma etching on the ceramic piece after mechanical processing so as to remove damage and particles on the surface to be processed of the ceramic piece;

specifically, the particles adhering to the surface to be treated of the ceramic member are generally chips or swarf in machining, and therefore the particles are of the same material as the ceramic member; the damage on the surface to be processed of the ceramic piece generally refers to a defect that a pit or a scratch, etc. is recessed inwards from the surface of the ceramic piece, so that if the damage on the surface of the ceramic piece is to be removed, the damaged part of the ceramic piece, i.e. the whole surface damaged layer, needs to be removed; the term "plasma etching" refers to that after the process gas for etching is excited into plasma, the plasma is given certain kinetic energy to bombard the surface of the ceramic piece, so that the surface material of the ceramic piece is sputtered and separated from the main body of the ceramic piece; or the chemical property of the plasma is utilized to react with the ceramic material to generate a gas product or a solid product easy to sublimate; or the kinetic energy and the chemical property of the plasma are simultaneously utilized, so that the plasma can bombard the surface material of the ceramic part and can also perform chemical reaction with the surface material of the plasma;

step S2: the surface to be processed of the ceramic piece is cleaned to remove the solid products generated on the surface to be processed of the ceramic piece in the plasma etching performed at the above-described step S1. Specifically, the solid product generated in step S1 generally has a sublimation property, and sublimates into gas at a low temperature, but due to the existence of intermolecular forces, a part of the solid product inevitably remains on the surface of the ceramic piece to be processed, and thus the surface of the ceramic piece to be processed needs to be cleaned to completely remove the remaining solid product.

According to the processing method of the ceramic piece, the surface material of the ceramic piece is removed in a whole layer by using the plasma etching process, so that particles attached to the surface to be processed of the ceramic piece and a damaged surface damage layer can be effectively removed. And because the precision of the plasma etching process is higher, the surface material of the ceramic part is removed by using the plasma etching process, and the removal amount can be accurately controlled by controlling the process conditions of the etching process, so that the surface damage of the ceramic part can be effectively removed, and the additional damage on the surface of the ceramic part can be avoided.

In some embodiments, as shown in fig. 4, the step S1, that is, the step of performing plasma etching on the ceramic piece, includes the following steps after the ceramic piece is placed in the etching chamber:

step S11: placing the ceramic piece in an etching chamber;

step S12: introducing process gas into the etching chamber to enable the internal pressure of the etching chamber to reach a preset pressure value;

step S13: starting an upper radio frequency power supply to excite the process gas into plasma;

specifically, the upper rf power supply is typically located at the top of the etch chamber for exciting the process gas into a plasma; in step S13 of this embodiment, the output power of the upper rf power supply is not limited, and it is sufficient that part or all of the process gas can be excited into plasma;

step S14: controlling the internal temperature of the etching chamber to be kept at a preset etching temperature, adjusting the output power of the upper radio frequency power supply to a first preset power value, and adjusting the output power of the lower radio frequency power supply to a second preset power value, so that the plasma bombards the surface to be processed of the ceramic piece under the action of gravity and chemically reacts with the material and particles of the surface to be processed of the ceramic piece, and damages and particles on the surface to be processed of the ceramic piece are removed. Wherein the lower rf power supply is generally configured to apply rf power to a chuck disposed in the etch chamber to attract plasma to bombard a workpiece to be processed on the chuck.

In the embodiment, the plasma bombards the surface to be processed of the ceramic piece under the action of gravity only, so that the bombarding force is as small as possible, and the additional damage or the increase of the surface roughness of the surface to be processed caused by the overlarge bombarding force is avoided.

In some embodiments, the predetermined etching temperature is greater than or equal to 60 ℃ and less than or equal to 70 ℃. The preset pressure value is more than or equal to 600mTorr and less than or equal to 900 mTorr; the first predetermined power is 1800W or more and 2200W or less to maintain the process gas in the etching chamber in a plasma state. Because the lower radio frequency power supply is used for attracting the plasma to move towards the ceramic part, the second preset power value is equal to 0W, so that the plasma is only under the action of gravity and is not influenced by Lorentz force, the bombardment force is reduced as much as possible, additional damage to the surface to be treated due to overlarge bombardment force is avoided, and the surface roughness of the surface to be treated is not increased. However, the present embodiment is not limited thereto, and the second predetermined power value may be selected to be close to 0W under the condition that the requirement for the surface roughness of the ceramic member is not high.

In some embodiments, the process gas comprises a main etch gas and an auxiliary etch gas. The main etching gas is used for carrying out chemical reaction with the surface material to be processed and the particles of the ceramic piece after being excited into plasma, and generating a solid product, wherein the solid product can have a lower boiling point so as to be capable of subliming into gas at a lower temperature, and therefore the gas can be discharged through an exhaust port of the etching chamber. The auxiliary etching gas is used for promoting the chemical reaction of the main etching gas and the surface material and particles to be processed of the ceramic piece after being excited into plasma.

In some embodiments, the ceramic part is made of alumina (Al)₂O₃) And (4) preparing. Accordingly, the main etch gas comprises chlorine gas (Cl)₂) (ii) a The auxiliary etching gas comprises an inert gas. Wherein the inert gas is argon (Ar), after the argon is excited into plasma, argon ions in a plasma state have certain kinetic energy, and under the action of gravity, the argon ions collide with the surface material to be processed of the ceramic piece and particles attached to the surface to be processed of the ceramic piece at a certain speed, so that Al-doped materials in the aluminum oxide material can be obtainedThe O bond is broken, and the chemical combination reaction of the chlorine ions and the aluminum ions can be promoted after the chlorine gas is excited into plasma. The chlorine ions and the aluminum ions are subjected to chemical combination reaction to generate solid aluminum chloride, and the aluminum chloride is easy to sublimate due to low melting point and boiling point, so that the sublimation of the aluminum chloride can be promoted by adjusting the internal temperature of the etching chamber, and the sublimated gaseous aluminum chloride is discharged from the air outlet of the chamber. In addition, the processing method of the ceramic piece provided by the embodiment is not only used for the alumina ceramic piece, but also can be applied to the ceramic piece made of materials such as silicon carbide and the like.

In some embodiments, the etching rate in step S1 may be adjusted by adjusting the gas flow ratio of the main etching gas and the auxiliary etching gas; specifically, the gas inflow ratio of the main etching gas to the auxiliary etching gas is less than or equal to 1:1 and greater than or equal to 1: 3.5.

On this basis, the step S12 of introducing the process gas into the etching chamber specifically includes the following steps:

and introducing main etching gas into the etching chamber at the first gas inflow rate, and introducing auxiliary etching gas into the etching chamber at the second gas inflow rate. Wherein the first intake air flow value is more than or equal to 150sccm and less than or equal to 300 sccm; the second intake air flow value is greater than or equal to 400sccm and less than or equal to 650 sccm. Under the gas condition, the main etching gas can be ensured to fully and uniformly react with the surface material to be treated of the ceramic piece and the particles adsorbed on the surface to be treated, and meanwhile, the etching reaction can be carried out at a proper speed.

In some embodiments, before the step S1, that is, after the step of machining the ceramic piece and before the step of plasma etching the ceramic piece, the method further comprises the following steps:

step S10: and baking the ceramic piece to dry the surface to be processed of the ceramic piece, namely heating the liquid remained on the surface of the ceramic piece to accelerate evaporation. This is done because during machining, transportation or storage, a certain amount of water vapor is adsorbed on the surface of the ceramic part, and if the water vapor directly enters the etching chamber, the subsequent etching reaction is affected.

In some embodiments, the step S2, namely, the step of cleaning the surface to be treated of the ceramic piece, specifically includes the following steps:

step S21: soaking the ceramic piece in a cleaning solution to remove solid products;

specifically, the cleaning solution may be, for example, a mixed solution of ammonia water and hydrogen peroxide, and the mixture ratio thereof is: ammonium monohydrate (NH)₄OH): hydrogen peroxide (H)₂O₂): water (H)₂O) ═ 1: 2: 5; and the cleaning solution should be maintained at a preset temperature, for example 30 ℃, during the soaking of the ceramic pieces;

step S22: and removing the residual cleaning solution on the surface to be treated of the ceramic piece.

In some embodiments, after the step of cleaning the surface to be treated of the ceramic piece, which is finished in step S2, the method further comprises the following steps:

step S3: and standing the ceramic piece until the stress on the surface of the ceramic piece is completely released.

Specifically, in step S3, the ceramic piece may be placed in a standing cabinet filled with nitrogen gas, the temperature inside the standing cabinet is controlled to be 20 ℃, and the ceramic piece is allowed to stand at this temperature for 1 hour, so that the stress on the surface of the ceramic piece is completely released.

As another technical solution, on the basis of the processing method of the ceramic part, the embodiment further provides a flow for performing surface treatment on the alumina ceramic part, which includes the following steps:

step S01: placing the ceramic piece in an oven, and baking the ceramic piece for a preset baking time at a preset baking temperature; specifically, the preset baking temperature is 110 ℃ for example, and the preset baking time is 45min for example, under the condition, the water vapor adsorbed on the surface of the ceramic piece can be completely removed;

step S02: putting the ceramic piece into an etching chamber, and fixing the ceramic piece at the central position in the etching chamber in a mechanical fixing mode so as to enable the subsequent etching process to be uniformly carried out; specifically, the mechanical fixing is, for example, placing a ceramic piece on a chuck; it should be noted that the surface of the fixed ceramic piece facing the top of the etching chamber is the surface to be processed, in other words, it should be noted that the surface of the ceramic piece to be processed faces upward as much as possible in the process of fixing the ceramic piece;

step S03: introducing chlorine into the etching chamber at the first gas inflow rate, and introducing argon into the etching chamber at the second gas inflow rate; specifically, the first intake air flow value is more than or equal to 150sccm and less than or equal to 300 sccm; the second intake air flow value is more than or equal to 400sccm and less than or equal to 650 sccm;

step S04: starting an upper radio frequency power supply to excite the process gas into plasma; in this step, the lower radio frequency power supply does not need to be turned on;

step S05: adjusting the output power of the upper radio frequency power supply to a first preset power value, and keeping the lower radio frequency power supply in a closed state, so that the plasma falls onto the surface to be processed of the ceramic piece at a certain speed only under the action of gravity; specifically, the first preset power value is greater than or equal to 1800W and less than or equal to 2200W; specifically, the etching duration can be preset in the step, and the etching amount, namely the thickness of the surface material of the removed ceramic piece, can be adjusted through the preset etching duration;

step S06: taking the ceramic piece out of the etching chamber, and soaking the ceramic piece in a cleaning tank for 1min to dissolve aluminum chloride remained on the surface of the ceramic piece by a cleaning solution in the cleaning tank;

step S07: taking out the ceramic piece from the cleaning tank, and soaking in a pure water tank for 2min to remove the cleaning solution remained on the surface of the ceramic piece;

step S08: taking out the ceramic piece from the pure water tank, putting the ceramic piece into a rotating tank, and continuously rotating for 45s at the rotating speed of 3000r/min so as to throw away liquid remained on the surface of the ceramic piece;

step S09: putting the ceramic piece into a standing cabinet;

step S10: and controlling the internal temperature of the standing cabinet to be kept at 20 ℃, and standing the ceramic piece for 1h at the temperature so as to completely release the stress on the surface of the ceramic piece.

The inventors have performed surface treatment on a plurality of ceramic samples using the above surface treatment process, and obtained the effects shown in the following table:

TABLE 1 comparison data sheet of the number of surface particles and the thickness of surface damage layer before and after surface treatment of a plurality of ceramic samples

As can be seen from the above table, the surface processing method provided by the embodiment can effectively reduce surface particles and surface damage of the ceramic part. Moreover, as can be seen from fig. 5 and 6, after the ceramic part is processed by the surface processing method provided by the embodiment, the particles attached to the surface of the ceramic part are obviously reduced, and most of the damaged layer on the surface of the ceramic part is effectively removed without adding new damage.

According to the processing method of the ceramic piece, the surface material of the ceramic piece is removed in a whole layer by using the plasma etching process, so that particles attached to the surface to be processed of the ceramic piece and a damaged surface damage layer can be effectively removed. And because the precision of the plasma etching process is higher, the surface material of the ceramic part is removed by using the plasma etching process, and the removal amount can be accurately controlled by controlling the process conditions of the etching process, so that the surface damage of the ceramic part can be effectively removed, and the additional damage on the surface of the ceramic part can be avoided.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.