A wet cleaning process for a semiconductor equipment electrostatic chuck

Abstract

The application relates to the technical field of part repair and regeneration, and relates to a wet cleaning process for a semiconductor equipment electrostatic chuck, which comprises the following steps: step one, ammonium fluoride immersion; the anode oxidation surface of the electrostatic chuck is protected by a tape, and the part is immersed in ammonium fluoride liquid; step two, hot water immersion; step three, polishing; the helium hole and the pulling hole of the working surface are protected by a circular tape, the part is fixed on a polisher, step four, high-pressure water cleaning; the protection is removed, and the polished electrostatic chuck is integrally washed by high-pressure water; step five, ultrasonic cleaning; and step six, drying; the blown dry part is placed in a dust-free oven for heating and drying. The surface deposition is effectively removed, the cleaning degree is improved, the reuse frequency of the part is increased, the part procurement cost is reduced, and the wet cleaning process has high industrial application value.

Description

Technical Field

[0001] This invention relates to the field of parts regeneration technology, specifically to a regeneration and cleaning method for electrostatic chucks. Background Technology

[0002] Electrostatic chucks are a core component of semiconductor processing equipment (such as plasma etching chambers), primarily used to pick up wafers, regulate wafer temperature, and maintain surface flatness. Because they need to be in direct contact with the wafer within the etching chamber, the stability, precision, and accuracy of the electrostatic chuck are crucial during the etching process. Electrostatic chucks typically have a short lifespan. During etching, uneven polymer deposition on the surface of the chuck can lead to increased particle size on the back side of the wafer. Since the components themselves are expensive, they require cleaning and regeneration for repeated use.

[0003] Currently, the cleaning and regeneration process for electrostatic chucks mainly relies on wet cleaning. US07052553 discloses a wet cleaning process for electrostatic chucks, which involves sequentially immersing the component in isopropanol and hydrogen peroxide, then sequentially wiping the surface with a mixed solution of nitric acid and fluorescent acid, a mixed solution of hydrochloric acid and hydrogen peroxide, and tetramethylammonium hydroxide (TMAH), followed by sequential immersion in hydrogen peroxide and ammonia solution, and then hydrochloric acid and hydrogen peroxide to obtain the cleaned product. This method is cumbersome, consumes a high amount of acid, and has poor operating environment and cleanliness. Furthermore, it suffers from the problem of residual deposits on the surface, resulting in unsatisfactory cleaning effects.

[0004] Therefore, it is of great significance to develop a new wet cleaning process that achieves high cleanliness and is easy to implement. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a wet cleaning process for electrostatic chucks of semiconductor equipment, which solves at least one of the above-mentioned technical problems.

[0006] This invention provides a wet cleaning process for electrostatic chucks of semiconductor devices, comprising the following steps:

[0007] Step 1: Soak in ammonium fluoride;

[0008] Protect the anodized surface of the electrostatic chuck with tape, and immerse the parts in ammonium fluoride solution for a total immersion time of 3-6 hours;

[0009] Step two, soak in hot water;

[0010] Place the electrostatic chuck on a fixed platform and soak it in 60℃ hot water for 2-5 hours;

[0011] Step 3, polishing;

[0012] Protect the helium gas vent and lifting hole on the working surface with round tape, fix the part on the grinder, set the grinder speed to 80-120 rpm, and the total grinding time is 2-10 hours.

[0013] Step 4: High-pressure water cleaning;

[0014] Remove the protective coating and rinse the polished electrostatic chuck with high-pressure water, setting the rinsing pressure to 2-6 MPa.

[0015] Step 5: Ultrasonic cleaning;

[0016] The components were moved to a Class 100 cleanroom for ultrasonic cleaning at a frequency of 4-10 W / in for 5-15 minutes, and then dried with nitrogen.

[0017] Step six, drying;

[0018] After being dried, the parts are placed in a dust-free oven for further heating and drying.

[0019] More preferably, in step one, the tape is an acid-resistant tape, preferably one or more of PET, PI, and PVC.

[0020] More preferably, in step one, the ammonium fluoride solution is a mixed solution of hydrofluoric acid and ammonium fluoride. The mixed solution includes 5%–10% hydrofluoric acid by mass, 25%–40% ammonium fluoride by mass, and the balance is deionized water.

[0021] In a further preferred embodiment, in step two, the hot water soaking process requires the parts to be removed or placed when the water temperature is below 50°C.

[0022] In a further preferred embodiment, in step three, the polishing paste is 3M polishing paste.

[0023] In a further preferred embodiment, in step five, the pure water overflow rate of the ultrasonic cleaning tank is greater than 250 L / h, and the pure water resistance is greater than 2 MΩ.

[0024] In a further preferred embodiment, in step six, a Teflon rod is placed on the partition of the dust-free oven, and then covered with a non-woven fabric pad. The distance between the upper end of the component and the partition should be greater than 5cm. After placement, the baking program is started.

[0025] In a further preferred embodiment, in step six, the oven temperature is set to 60-80℃, the constant temperature time is set to 5-10 hours, and after the program is completed, the oven is opened at a temperature below 40℃ for dust-free packaging.

[0026] A wet cleaning process for electrostatic chucks in semiconductor equipment includes the following steps:

[0027] Step 1: Soak in ammonium fluoride;

[0028] Protect the anodized surface of the electrostatic chuck with tape, then immerse the component in ammonium fluoride solution for a total soaking time of 3 hours. The ammonium fluoride solution is a mixed solution of hydrofluoric acid and ammonium fluoride, comprising 6% hydrofluoric acid by mass, 30% ammonium fluoride by mass, and the remainder being deionized water.

[0029] Step two, soak in hot water;

[0030] Place the electrostatic chuck on a fixed platform and soak it in 60℃ hot water for 2 hours;

[0031] Step 3, polishing;

[0032] Protect the helium gas vent and lifting hole on the working surface with round tape, fix the part on the grinder, set the grinder speed to 90 rpm, and the total grinding time is 2 hours;

[0033] Step 4: High-pressure water cleaning;

[0034] Remove the protective coating and rinse the polished electrostatic chuck with high-pressure water at a pressure of 3 MPa.

[0035] Step 5: Ultrasonic cleaning;

[0036] The components were moved to a Class 100 cleanroom for ultrasonic cleaning. The ultrasonic cleaning tank had a pure water overflow rate of more than 250 L / h, a pure water resistance of more than 2 MΩ, an ultrasonic frequency of 5 W / in, and an ultrasonic time of 5 min. Finally, the components were dried with nitrogen.

[0037] Step six, drying;

[0038] After the parts are dried, they are placed in a cleanroom oven for heating and drying. Teflon rods are placed on the partitions of the cleanroom oven and covered with non-woven fabric. The distance between the top of the parts and the partitions should be greater than 5cm. After the parts are placed, the baking program is started.

[0039] The oven temperature is set to 65℃, the constant temperature time is set to 6 hours, and the oven is opened at a temperature below 40℃ after the program is completed for dust-free packaging.

[0040] This invention provides a wet cleaning process for electrostatic chucks in semiconductor devices, with the following advantages:

[0041] By using chemical cleaning, the metal deposit film on the surface of the electrostatic chuck is converted into soluble gold ions. Then, physical grinding is used to remove the deposited areas with strong adhesion. Compared with existing methods, this invention uses a chemical-physical alternation method, which effectively removes surface deposits, improves the cleanliness, increases the number of times the parts can be reused, and reduces the cost of parts procurement, thus having high industrial application value. Attached Figure Description

[0042] Figure 1 This is a flowchart of Embodiment 1 of the present invention;

[0043] Figure 2 This is a SEM-EDX image of the component surface after cleaning according to Embodiment 1 of the present invention;

[0044] Figure 3 This is a SEM-EDX image of the component surface after cleaning, as shown in Embodiment 2 of the present invention.

[0045] Figure 4 This is a SEM-EDX image of the surface of the component after cleaning, as shown in Embodiment 3 of the present invention. Detailed Implementation

[0046] A wet cleaning process for electrostatic chucks in semiconductor equipment includes the following steps:

[0047] Step 1: Ammonium fluoride soaking; protect the anodized surface of the electrostatic chuck with tape, and immerse the component in the ammonium fluoride solution for a total soaking time of 3-6 hours;

[0048] Step 2, hot water soaking; place the electrostatic chuck on a fixed platform and soak it in 60℃ hot water for 2-5 hours;

[0049] Step 3, Grinding; Protect the helium gas holes and lifting holes on the working surface with round tape, fix the part on the grinding machine, set the grinding machine speed to 80-120 rpm, and the total grinding time is 2-10 hours.

[0050] Step 4, high-pressure water cleaning; remove the protective layer and rinse the polished electrostatic chuck with high-pressure water, setting the rinsing pressure to 2-6 MPa.

[0051] Step 5, ultrasonic cleaning; transport the parts to a Class 100 cleanroom for ultrasonic cleaning, with an ultrasonic frequency of 4-10w / in and an ultrasonic time of 5-15min, and finally dry with nitrogen.

[0052] Step 6, Drying; After drying, the parts are placed in a dust-free oven for heating and drying.

[0053] See Figure 1 Example 1: A wet cleaning process for electrostatic chucks of semiconductor equipment, comprising the following steps:

[0054] Step 1: Soak in ammonium fluoride;

[0055] Protect the anodized surface of the electrostatic chuck with tape, then immerse the component in ammonium fluoride solution for a total soaking time of 3 hours. The ammonium fluoride solution is a mixed solution of hydrofluoric acid and ammonium fluoride, comprising 6% hydrofluoric acid by mass, 30% ammonium fluoride by mass, and the remainder being deionized water.

[0056] Step two, soak in hot water;

[0057] Place the electrostatic chuck on a fixed platform and soak it in 60℃ hot water for 2 hours;

[0058] Step 3, polishing;

[0059] Protect the helium gas vent and lifting hole on the working surface with round tape, fix the part on the grinder, set the grinder speed to 90 rpm, and the total grinding time is 2 hours;

[0060] Step 4: High-pressure water cleaning;

[0061] Remove the protective coating and rinse the polished electrostatic chuck with high-pressure water at a pressure of 3 MPa.

[0062] Step 5: Ultrasonic cleaning;

[0063] The components were moved to a Class 100 cleanroom for ultrasonic cleaning. The ultrasonic cleaning tank had a pure water overflow rate of more than 250 L / h, a pure water resistance of more than 2 MΩ, an ultrasonic frequency of 5 W / in, and an ultrasonic time of 5 min. Finally, the components were dried with nitrogen.

[0064] Step six, drying;

[0065] After the parts are dried, they are placed in a cleanroom oven for heating and drying. Teflon rods are placed on the partitions of the cleanroom oven and covered with non-woven fabric. The distance between the top of the parts and the partitions should be greater than 5cm. After the parts are placed, the baking program is started.

[0066] The oven temperature is set to 65℃, the constant temperature time is set to 6 hours, and the oven is opened at a temperature below 40℃ after the program is completed for dust-free packaging.

[0067] SEM-EDX images of the cleaned component surface are shown below. Figure 2 Under 1000x magnification, the content of elements other than the matrix components such as C, O, and Al is less than 1%.

[0068] Example 2: A wet cleaning process for electrostatic chucks of semiconductor equipment, comprising the following steps:

[0069] Step 1: Soak in ammonium fluoride;

[0070] Protect the anodized surface of the electrostatic chuck with tape, then immerse the component in ammonium fluoride solution for a total soaking time of 4 hours. The ammonium fluoride solution is a mixed solution of hydrofluoric acid and ammonium fluoride, which includes 7% hydrofluoric acid by mass, 30% ammonium fluoride by mass, and the remainder is deionized water.

[0071] Step two, soak in hot water;

[0072] Place the electrostatic chuck on a fixed platform and soak it in 60℃ hot water for 5 hours;

[0073] Step 3, polishing;

[0074] Protect the helium gas vent and lifting hole on the working surface with round tape, fix the part on the grinder, set the grinder speed to 100 rpm, and the total grinding time is 4 hours;

[0075] Step 4: High-pressure water cleaning;

[0076] Remove the protective coating and rinse the polished electrostatic chuck with high-pressure water at a pressure of 3 MPa.

[0077] Step 5: Ultrasonic cleaning;

[0078] The components were moved to a Class 100 cleanroom for ultrasonic cleaning. The ultrasonic cleaning tank had a pure water overflow rate of more than 250 L / h, a pure water resistance of more than 2 MΩ, an ultrasonic frequency of 5 W / in, and an ultrasonic time of 5 min. Finally, the components were dried with nitrogen.

[0079] Step six, drying;

[0080] After the parts are dried, they are placed in a cleanroom oven for heating and drying. Teflon rods are placed on the partitions of the cleanroom oven and covered with non-woven fabric. The distance between the top of the parts and the partitions should be greater than 5cm. After the parts are placed, the baking program is started.

[0081] The oven temperature is set to 65℃, the constant temperature time is set to 3 hours, and the oven is opened at a temperature below 40℃ after the program is completed for dust-free packaging.

[0082] SEM-EDX images of the cleaned component surface are shown below. Figure 3 Under 1000x magnification, the content of elements other than the matrix components such as C, O, and Al is less than 1%.

[0083] Example 3: A wet cleaning process for electrostatic chucks of semiconductor equipment, comprising the following steps:

[0084] Step 1: Soak in ammonium fluoride;

[0085] Protect the anodized surface of the electrostatic chuck with tape, then immerse the component in ammonium fluoride solution for a total soaking time of 5 hours. The ammonium fluoride solution is a mixed solution of hydrofluoric acid and ammonium fluoride, comprising 6% hydrofluoric acid by mass, 40% ammonium fluoride by mass, and the remainder being deionized water.

[0086] Step two, soak in hot water;

[0087] Place the electrostatic chuck on a fixed platform and soak it in 60℃ hot water for 5 hours;

[0088] Step 3, polishing;

[0089] Protect the helium gas vent and lifting hole on the working surface with round tape, fix the part on the grinder, set the grinder speed to 120 rpm, and the total grinding time is 8 hours;

[0090] Step 4: High-pressure water cleaning;

[0091] Remove the protective coating and rinse the polished electrostatic chuck with high-pressure water at a pressure of 3 MPa.

[0092] Step 5: Ultrasonic cleaning;

[0093] The components were moved to a Class 100 cleanroom for ultrasonic cleaning. The ultrasonic cleaning tank had a pure water overflow rate of more than 250 L / h, a pure water resistance of more than 2 MΩ, an ultrasonic frequency of 5 W / in, and an ultrasonic time of 5 min. Finally, the components were dried with nitrogen.

[0094] Step six, drying;

[0095] After the parts are dried, they are placed in a cleanroom oven for heating and drying. Teflon rods are placed on the partitions of the cleanroom oven and covered with non-woven fabric. The distance between the top of the parts and the partitions should be greater than 5cm. After the parts are placed, the baking program is started.

[0096] The oven temperature is set to 65℃, the constant temperature time is set to 5 hours, and the oven is opened at a temperature below 40℃ after the program is completed for dust-free packaging.

[0097] SEM-EDX images of the cleaned component surface are shown below. Figure 4 At 1000x magnification, the content of impurity elements other than the matrix components such as C, O, and Al is less than 1%.

[0098] Comparative Example 1

[0099] US07052553 discloses a wet cleaning process for electrostatic chucks. After cleaning, chemical extraction is used to dissolve contaminants on the surface of the electrostatic chucks into a solution, which is then analyzed using ICP-MS to confirm the degree of surface cleanliness. The results are shown in the table below:

[0100]

[0101]

[0102] A comparison of the results of Example 1 and Comparative Example 1 shows that the process of the present invention is more effective than the original process in removing elements such as Al and Ti.

[0103] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1.A wet cleaning process of a semiconductor equipment electrostatic chuck, comprising the following steps: Step 1, soaking in ammonium fluoride; protecting the anodized surface of the electrostatic chuck with adhesive tape, and soaking the part in ammonium fluoride solution for 3-6 hours; Step 2, soaking in hot water; placing the electrostatic chuck on a fixed platform and soaking it in 60℃ hot water for 2-5 hours; Step 3, polishing; protecting the helium holes and lifting holes on the working surface with round adhesive tape, fixing the part on a polisher, setting the rotation speed of the polisher to 80-120rpm, and polishing for a total of 2-10 hours; Step 4, high-pressure water cleaning; removing the protection and washing the polished electrostatic chuck with high-pressure water, and setting the washing pressure to 2-6MPa; Step 5, ultrasonic cleaning; Step 6, drying; and placing the dried part in a dust-free oven for heating and drying. In Step 1, the adhesive tape is acid-proof tape. In Step 1, the adhesive tape is one or more of PET, PI, and PVC. In Step 1, the ammonium fluoride solution is a mixed solution of fluoric acid and ammonium fluoride, and the mixed solution comprises 5-10wt% fluoric acid, 25-40wt% ammonium fluoride, and the balance deionized water. In Step 2, the part is taken out and placed when the water temperature is below 50℃. In Step 3, the polishing paste is 3M polishing paste. In Step 5, the ultrasonic cleaning tank has a pure water overflow rate of greater than 250L / h and a pure water resistance of greater than 2MΩ. In Step 6, a Teflon rod is placed on the partition of the dust-free oven, which is then covered with a non-woven fabric pad, and the distance between the upper end of the part and the partition should be greater than 5cm, and the baking program is started after the part is placed. In Step 6, the oven temperature is set to 60-80℃, the constant temperature time is set to 5-10 hours, and the oven is opened below 40℃ after the program ends for dust-free packaging. 10.A wet cleaning process of a semiconductor equipment electrostatic chuck, comprising the following steps: Step 1, soaking in ammonium fluoride; protecting the anodized surface of the electrostatic chuck with adhesive tape, and soaking the part in ammonium fluoride solution for 3 hours; the ammonium fluoride solution is a mixed solution of fluoric acid and ammonium fluoride, and the mixed solution comprises 6wt% fluoric acid, 30wt% ammonium fluoride, and the balance deionized water; Step 2, soaking in hot water; placing the electrostatic chuck on a fixed platform and soaking it in 60℃ hot water for 2 hours; Step 3, polishing; protecting the helium holes and lifting holes on the working surface with round adhesive tape, fixing the part on a polisher, setting the rotation speed of the polisher to 90rpm, and polishing for a total of 2 hours; Step 4, high-pressure water cleaning; removing the protection and washing the polished electrostatic chuck with high-pressure water, and setting the washing pressure to 3MPa; Step 5, ultrasonic cleaning; Step 6, drying; and placing the dried part in a dust-free oven for heating and drying; a Teflon rod is placed on the partition of the dust-free oven, which is then covered with a non-woven fabric pad, and the distance between the upper end of the part and the partition should be greater than 5cm, and the baking program is started after the part is placed; and the oven temperature is set to 65℃, the constant temperature time is set to 6 hours, and the oven is opened below 40℃ after the program ends for dust-free packaging. The parts were transported to a Class 100 clean room for ultrasonic cleaning at a power density of 4-10 w / in 2 , for 5-15 minutes, and finally dried with nitrogen. ​ ​ 2. A wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 1, wherein: ​ 3. A wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 2, wherein: ​ 4. The wet cleaning process for a semiconductor equipment electrostatic chuck as claimed in claim 1, wherein: ​ 5. The wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 1 wherein: ​ 6. A wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 1, wherein: ​ 7. A wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 1, wherein: ​ 8. A wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 1, wherein: ​ 9. A wet cleaning process for a semiconductor equipment electrostatic chuck as defined in claim 1, wherein: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The components are transported to a 100-level clean room for ultrasonic cleaning, the overflow rate of the ultrasonic cleaning tank is greater than 250 L / h, the pure water resistance is greater than 2 MΩ, the ultrasonic power density is 5 w / in 22 , the ultrasonic time is 5 min, and finally dried with nitrogen; ​ ​ ​

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