阅读说明：本技术 基板清洗方法及清洗装置 (Substrate cleaning method and cleaning device ) 是由 王晖 王希 陈福平 张晓燕 陈福发 于 2018-02-07 设计创作，主要内容包括：本发明揭示了一种基板清洗方法,包括步骤：将基板放置在基板保持装置上；对基板实施少气泡或无气泡的预湿润工艺；实施超声波或兆声波清洗工艺清洗基板。(The invention discloses a substrate cleaning method, which comprises the following steps: placing a substrate on a substrate holding device; carrying out a pre-wetting process with little or no bubbles on the substrate; and cleaning the substrate by ultrasonic or megasonic cleaning.)

1. A method of cleaning a substrate, comprising:

placing a substrate on a substrate holding device;

carrying out a pre-wetting process with little or no bubbles on the substrate;

and cleaning the substrate by ultrasonic or megasonic cleaning.

2. The method of claim 1, wherein the bubble-less or bubble-free pre-wetting process comprises establishing a vacuum environment around the substrate and then providing a pre-wetting chemical solution or chemical mist onto the substrate.

3. The method of claim 2, wherein the degree of vacuum is set at 25Torr and above.

4. The method of claim 1, wherein the bubble-less or bubble-free pre-wetting process comprises vaporizing a pre-wetting chemical solution and then providing the vaporized liquid molecules to the substrate surface to form a layer of pre-wetting chemical on the substrate.

5. The method of claim 4, wherein the pre-wetting chemical solution is converted to gas phase molecules using a sonic generation process.

6. The method of claim 5, further comprising heating the vaporized liquid molecules to a temperature greater than the temperature of the substrate.

7. The method of claim 5, further comprising cooling the substrate to a temperature below the temperature of the vaporized liquid molecules.

8. The method of claim 4, wherein the pre-wetting chemical solution is converted to gas phase molecules using a heating process.

9. The method of claim 4, wherein the pre-wetting chemical solution comprises a surfactant or an additive.

10. The method of claim 9, wherein the surfactant is a carboxyl-containing ethylenediaminetetraacetic acid (EDTA) or tetracarboxyldiaminopropionic acid (EDTP) acid or salt.

11. The method of claim 4, wherein the pre-wetting chemical solution includes an oxidizer to oxidize the substrate surface from hydrophobic to hydrophilic.

12. The method of claim 11, wherein the oxidizing agent is an ozone solution or a SC1 solution.

13. The method of claim 1, further comprising removing scum or burrs to improve the surface smoothness of the recessed areas of the substrate prior to subjecting the substrate to the bubble-less or bubble-free pre-wetting process.

14. A substrate cleaning apparatus, comprising:

a first chamber configured to be connected to a pump to form a vacuum environment in the first chamber;

a substrate holding device configured to be disposed in the first chamber to hold the substrate;

at least one showerhead configured to provide a pre-wetting chemical solution or chemical mist to a surface of the substrate to form a bubble-less or bubble-free chemical solution layer on the substrate; and

a second chamber configured with an ultrasonic or megasonic apparatus to clean the substrate.

15. The apparatus of claim 14, further comprising a pre-processing unit configured to remove dross or burrs in the recessed area of the substrate.

16. The apparatus of claim 14, wherein a vacuum level of the first chamber is set at 25Torr and above.

17. The apparatus of claim 14, further comprising a rotational drive configured to couple to the substrate holding apparatus.

18. A substrate cleaning apparatus, comprising:

a chamber configured to be connected to a pump to form a vacuum environment in the chamber;

a substrate holding device configured to be disposed in the chamber to hold the substrate;

at least one nozzle configured to provide a pre-wetting chemical solution or chemical mist to a surface of the substrate to form a bubble-less or bubble-free chemical solution layer on the substrate after forming a vacuum environment in the chamber; and

an ultrasonic or megasonic apparatus configured to clean a substrate.

19. The apparatus of claim 18, further comprising a pre-processing unit configured to remove dross or burrs in the recessed area of the substrate.

20. The apparatus of claim 18, wherein the degree of vacuum is set at 25Torr and above.

21. A substrate cleaning apparatus, comprising:

a first chamber configured to be connected to a vaporizing unit configured to convert the pre-wetting chemical solution into a gaseous state;

a substrate holding device configured to be disposed in the first chamber to hold the substrate;

at least one spray head configured to be coupled to the vaporizing unit to provide vaporized liquid molecules to the substrate surface to form a bubble-less or bubble-free pre-wetting chemical layer on the substrate; and

a second chamber configured with an ultrasonic or megasonic apparatus to clean the substrate.

22. The apparatus of claim 21, further comprising a pre-processing unit configured to remove dross or burrs in the recessed area of the substrate.

23. A substrate cleaning apparatus, comprising:

a chamber;

a vaporization unit configured to convert the pre-wetting chemical solution into a gaseous state;

a substrate holding device configured to be disposed in the chamber to hold the substrate;

at least one spray head configured to be coupled to the vaporizing unit to provide vaporized liquid molecules to the substrate surface to form a bubble-less or bubble-free pre-wetting chemical layer on the substrate;

at least one nozzle configured to supply a chemical solution or a chemical mist for cleaning to a surface of the substrate to clean the substrate; and

an ultrasonic or megasonic apparatus configured to clean a substrate.

24. The apparatus of claim 23, further comprising a pre-processing unit configured to remove dross or burrs in the recessed area of the substrate.

Technical Field

The present invention relates to a method and apparatus for cleaning a substrate. And more particularly to the application of sonic energy to a pretreatment process prior to substrate cleaning to avoid destructive implosion of bubbles during substrate cleaning and thereby more effectively remove particles from the patterned structures on the substrate.

Background

Semiconductor devices are fabricated on semiconductor substrates using many different processing steps to create transistors and interconnect elements. In recent years, transistors have evolved from two dimensions to three dimensions, such as finFET transistors and 3D NAND memories. To electrically connect the transistor terminals to the semiconductor substrate, conductive (e.g., metal) trenches, vias, and the like are formed in the dielectric material as part of the semiconductor device. The trenches and vias may transfer electrical signals and energy between transistors, internal circuitry, and external circuitry.

In order to form finFET transistors and interconnect elements on a semiconductor substrate, the semiconductor substrate needs to go through a number of steps, such as masking, etching and deposition, to form the required electronic circuitry. In particular, the multi-layer masking and plasma etching steps may pattern finFET, 3D NAND flash memory cells and/or recessed regions in a dielectric layer of a semiconductor substrate as trenches and vias for fin and/or interconnect elements of the transistors. Wet cleaning is required to remove particles and contaminants generated in the fin structures and/or trenches and vias during etching or photoresist ashing. In particular, fin and/or trench and via sidewall loss is critical to maintaining critical dimensions as device fabrication nodes extend to 16 or 14nm and smaller. To reduce or eliminate sidewall loss, it is important to use mild or dilute chemical solutions, sometimes deionized water alone. However, dilute chemical or deionized water is generally not effective in removing particles within fin structures, 3D NAND holes, and/or trenches and vias. Therefore, in order to effectively remove these particles, it is necessary to use a mechanical force such as ultrasonic waves or megasonic waves. Ultrasonic or megasonic waves can generate cavitation oscillations to provide mechanical force to the substrate structure. Violent cavitation oscillations such as unstable cavitation oscillations or microjets will damage these patterned structures. Maintaining stable or controlled cavitation oscillations is a key parameter in controlling the mechanical force damage limit and effectively removing particles.

Fig.1A and 1B depict unstable cavitation oscillations damaging a pattern structure 1030 on a substrate 1010 during cleaning of the substrate 1010. Unstable cavitation oscillations may be generated by the sonic energy used to clean the substrate 1010. As shown in fig.1A and 1B, the microjets caused by implosions of the bubbles 1050 occur above the tops of the pattern structures 1030 and are violent (up to several thousand atmospheres and several thousand degrees celsius), which can damage the pattern structures 1030 on the substrate 1010, particularly when the feature size t is reduced to 70nm or less.

Damage to the substrate pattern structure caused by microjets caused by implosion of bubbles is overcome by controlling cavitation oscillation of the bubbles during cleaning. Stable or controlled cavitation oscillations can be achieved over the entire substrate to avoid damage to the patterned structures, as disclosed in PCT/CN2015/079342, patent application number filed 5/20/2015.

In some cases, even if the power intensity of ultrasonic waves or megasonic waves used to clean the substrate is reduced to a very low level (almost no particle removal rate), damage of the pattern structure on the substrate may occur. The number of damages is small (below 100). However, in general, the number of bubbles is tens of thousands during ultrasonic or megasonic assisted cleaning. The number of damaged pattern structures on the substrate does not match the number of bubbles. The mechanism of this phenomenon is unknown.

Referring to fig.2A, in the ultrasonic or megasonic assisted cleaning of the substrate, there is a phenomenon that damage of the pattern structure 2030 on the substrate 2010 occurs although the power intensity of the ultrasonic or megasonic waves for cleaning the substrate 2010 is reduced to a very low level (almost no particle removal rate). In addition, it is typical that the single wall of the patterned structure 2030 is damaged. Two examples are given in fig. 2A. One example is where the single walls of the pattern structures 2030 are exfoliated toward one side, and another example is where a portion of the single walls of the pattern structures 2030 are removed. Although only two examples are shown in fig.2A, it should be appreciated that other similar damage may occur. What caused these damages to occur?

Referring to fig. 2B-2D, during substrate cleaning, small bubbles 2050, 2052 tend to adhere to solid surfaces, such as the surface of substrate 2010 or the sidewalls of patterned structure 2030, as shown in fig.2B and 2C. When the bubbles 2050, 2052 are attached to the surface of the substrate 2010 or the side walls of the pattern structure 2030, for example, the bubbles 2052 are attached to the bottom corners of the pattern structure 2030 and the bubbles 2050 are attached to the single side walls of the pattern structure 2030, once these bubbles 2050, 2052 implode, the pattern structure 2030 is peeled off from the sub-layer on the substrate 2010 in the direction in accordance with the force direction of the implosion of the bubbles acting on the single side walls, or a part of the single side walls of the pattern structure 2030 is removed, as shown in fig. 2A. Although implosions are not as strong as microjets, the energy of small bubble implosions can also damage pattern structure 2030 due to the attachment of bubbles 2050, 2052 to the surface of substrate 2010 and the sidewalls of pattern structure 2030.

In addition, in wet processes, small bubbles may coalesce into larger bubbles. Since the bubbles tend to adhere to the solid surface, on which, for example, the pattern structure and the substrate surface, the incorporation of the bubbles increases the risk of implosion of the bubbles on the pattern structure, particularly in critical geometric parts.

Fig.3A to 3H disclose a mechanism of implosion of bubbles attached to a substrate to damage a pattern structure on the substrate during a wet cleaning process using ultrasonic waves or megasonic waves according to the present invention. Fig.3A illustrates that a cleaning liquid 3070 is delivered onto the surface of the substrate 3010 having the pattern structure 3030, and at least one bubble 3050 is attached to a bottom corner of the pattern structure 3030. In the positive acoustic pressure operation of the ultrasonic wave or the megasonic wave shown in fig.3B, F1 is the ultrasonic wave or the megasonic wave pressure acting on the bubble 3050, F2 is the reaction force acting on the bubble 3050 generated by the substrate 3010 when the bubble 3050 is pressed against the substrate 3010, and F3 is the reaction force acting on the bubble 3050 generated by the side wall of the pattern structure 3030 when the bubble 3050 is pressed against the side wall of the pattern structure 3030. In the ultrasonic or megasonic negative sound pressure operation shown in fig.3C and 3D, the bubble 3050 expands and becomes large because the ultrasonic or megasonic negative force stretches the bubble 3050. During the expansion of the bubble volume, F1 ' is the force of bubble 3050 pushing cleaning solution 3070, F2 ' is the force of bubble 3050 pushing substrate 3010, and F3 ' is the force of bubble 3050 pushing the sidewall of graphical structure 3030. After the positive sound pressure and the negative sound pressure of the ultrasonic wave or the megasonic wave are alternately applied for several cycles, the gas temperature in the bubble becomes higher and higher, the bubble volume becomes larger and larger, and finally, the bubble implosion 3051 occurs, which generates an implosion force F1 "acting on the cleaning liquid 3070, a force F2" acting on the substrate 3010, and a force F3 "acting on the side wall of the pattern structure 3030, as shown in fig. 3G. The implosion force causes the sidewalls of the graphical structure 3030 to be damaged, as shown in FIG. 3H.

In order to avoid damage to the pattern structure on the substrate due to implosion of bubbles during ultrasonic or megasonic assisted wet cleaning, it is preferable to separate the bubbles from the surface of the pattern structure and the surface of the substrate before applying sonic energy to the cleaning liquid to clean the substrate, as disclosed in patent application No. PCT/CN2018/073723 filed on 23/1/2018. However, it is difficult to separate all bubbles from the surface of the pattern structure. Therefore, the remaining bubbles on the surface of the pattern structure may cause damage to the pattern structure on the substrate.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a substrate cleaning method and a cleaning apparatus.

According to an embodiment of the present invention, a substrate cleaning method is provided, including: placing a substrate on a substrate holding device; carrying out a pre-wetting process with little or no bubbles on the substrate; and cleaning the substrate by ultrasonic or megasonic cleaning.

According to an embodiment of the present invention, there is provided a substrate cleaning apparatus including: a first chamber configured to be connected to a pump to form a vacuum environment in the first chamber; a substrate holding device configured to be disposed in the first chamber to hold the substrate; at least one showerhead configured to provide a pre-wetting chemical solution or chemical mist to a surface of the substrate to form a bubble-less or bubble-free chemical solution layer on the substrate; and a second chamber configured with an ultrasonic or megasonic apparatus to clean the substrate.

According to another embodiment of the present invention, there is provided a substrate cleaning apparatus including: a chamber configured to be connected to a pump to form a vacuum environment in the chamber; a substrate holding device configured to be disposed in the chamber to hold the substrate; at least one nozzle configured to provide a pre-wetting chemical solution or chemical mist to a surface of the substrate to form a bubble-less or bubble-free chemical solution layer on the substrate after forming a vacuum environment in the chamber; and an ultrasonic or megasonic device configured to clean the substrate.

According to still another embodiment of the present invention, there is provided a substrate cleaning apparatus including: a first chamber configured to be connected to a vaporizing unit configured to convert the pre-wetting chemical solution into a gaseous state; a substrate holding device configured to be disposed in the first chamber to hold the substrate; at least one spray head configured to be coupled to the vaporizing unit to provide vaporized liquid molecules to the substrate surface to form a bubble-less or bubble-free pre-wetting chemical layer on the substrate; and a second chamber configured with an ultrasonic or megasonic apparatus to clean the substrate.

According to another embodiment of the present invention, there is provided a substrate cleaning apparatus including: a chamber; a vaporization unit configured to convert the pre-wetting chemical solution into a gaseous state; a substrate holding device configured to be disposed in the chamber to hold the substrate; at least one spray head configured to be coupled to the vaporizing unit to provide vaporized liquid molecules to the substrate surface to form a bubble-less or bubble-free pre-wetting chemical layer on the substrate; at least one nozzle configured to supply a chemical solution or a chemical mist for cleaning to a surface of the substrate to clean the substrate; and an ultrasonic or megasonic device configured to clean the substrate.

In summary, the present invention applies a pre-wetting process with little or no bubbles to the substrate before the substrate is cleaned by the ultrasonic or megasonic cleaning process, so that when the ultrasonic or megasonic cleaning process is performed, the pattern structure on the substrate is effectively prevented from being damaged by implosion of bubbles, and the bubbles do not tend to attach to the surface of the pattern structure any more or the bubbles near the surface of the pattern structure are easily removed before the bubbles attach to the surface of the pattern structure by the pre-treatment of the substrate. In this way, bubble implosion can be better controlled by ultrasonic or megasonic power control, independent of bubble accumulation or adherence on the surface of the patterned structure, and particularly independent of critical geometry.

Drawings

FIGS. 1A-1B depict a schematic diagram of a pattern on a substrate damaged by unstable cavitation oscillations during cleaning.

Fig.2A to 2D are diagrams illustrating a pattern structure damaged by implosion of bubbles attached to a surface of the pattern structure on a substrate.

Fig.3A to 3H are schematic diagrams illustrating a mechanism in which bubbles attached to the surface of the pattern structure on the substrate implode to damage the pattern structure.

Fig.4A to 4B illustrate a schematic view of an apparatus for cleaning a substrate according to an embodiment of the present invention.

FIG.5 depicts a schematic view of an apparatus for cleaning a substrate according to another embodiment of the invention.

Fig.6A to 6B illustrate schematic views of an apparatus for cleaning a substrate according to still another embodiment of the present invention.

FIG.7 depicts a schematic view of an apparatus for cleaning a substrate according to yet another embodiment of the invention.

Fig.8A to 8B illustrate a schematic view of a substrate cleaning method according to an embodiment of the present invention.

Fig.9A to 9D are schematic views illustrating a substrate cleaning method according to another embodiment of the present invention.

Detailed Description

Referring to fig.4A to 4B, a substrate cleaning apparatus according to an embodiment of the present invention is disclosed. The apparatus is capable of pre-treating the substrate prior to a subsequent ultrasonic or megasonic cleaning process to obtain a bubble-free or bubble-free substrate surface. The apparatus includes a pre-wetting chamber 4020 and a cleaning chamber 4000. The substrate 4010 is pretreated in the pre-wetting chamber 4020 to obtain a bubble-less or bubble-free pre-wetted surface, and then the substrate 4010 is transferred into the cleaning chamber 4000 for a subsequent ultrasonic or megasonic cleaning process. Fig.4A discloses a pre-wetting chamber 4020. The pre-wetting chamber 4020 includes a door for moving the substrate into or out of the pre-wetting chamber 4020, a vacuum port 4022 connected to a vacuum pump to create a vacuum environment in the pre-wetting chamber 4020, a substrate holder 4021 for holding the substrate 4010 in the pre-wetting chamber 4020, a rotation driving device 4024 for driving the substrate 4010 to rotate, and at least one shower head 4023 located above the substrate 4010 for supplying a pre-wetting chemical solution or chemical mist to the surface of the substrate 4010 to form a bubble-less or bubble-free chemical liquid layer on the substrate 4010. In one embodiment, a plurality of showerheads 4023 are used to uniformly distribute the pre-wetting chemical solution on the surface of the substrate 4010. The degree of vacuum in the pre-wet chamber 4020 is set to 25Torr or more. Fig.4B discloses wash chamber 4000. The cleaning chamber 4000 includes a substrate support 4002 holding a substrate 4010, a cleaning cup cover 4001 disposed around the substrate support 4002 to prevent a cleaning liquid 4070 from splashing, a rotary actuator 4003 connected to the substrate support 4002 to drive the substrate support 4002 to rotate, a fan filter unit 4015(FFU) disposed at the top of the cleaning chamber 4000, at least one exhaust port 4017, a swing arm 4005 mounted with an ultrasonic or megasonic device 4006 to transmit sonic energy to the cleaning liquid 4070 to clean the substrate 4010, a plurality of nozzle arms 4008, each nozzle arm 4008 being mounted with at least one nozzle 4009 to supply a chemical liquid, a chemical mist, or a dry gas to the surface of the substrate 4010.

According to an embodiment of the present invention, a substrate cleaning method is provided, including:

step 1: the substrate 4010 is transferred into the pre-wetting chamber 4020, and the substrate 4010 is held by the substrate holder 4021.

Step 2: the door of the pre-wet chamber 4020 is closed and vacuum is drawn through the vacuum port 4022 to the pre-wet chamber 4020 to establish a vacuum environment within the pre-wet chamber 4020 at a set time. The degree of vacuum in the pre-wet chamber 4020 is set to 25Torr or more.

And step 3: after the vacuum environment is formed, the substrate 4010 is rotated at 100-.

And 4, step 4: the substrate 4010 is rotated at a rotation speed of 400-.

And 5: the substrate 4010 is transferred from the pre-wetting chamber 4020 to the cleaning chamber 4000, and the substrate 4010 is held by the substrate holder 4002 in the cleaning chamber 4000.

Step 6: the substrate 4010 is driven to rotate at a set low rotation speed, 10RPM to 1000 RPM.

And 7: the nozzle arm 4008 is swung into position over the surface of the substrate 4010 to provide a cleaning solution to the surface of the substrate 4010. A variety of chemical solutions may be used in this step.

And 8: a cleaning fluid is supplied to the surface of the substrate 4010 for an ultrasonic or megasonic cleaning process.

And step 9: the ultrasonic or megasonic device 4006 is moved down to a certain height from the surface of the substrate 4010, and a gap between the ultrasonic or megasonic device 4006 and the surface of the substrate 4010 is filled with a cleaning solution as a medium for transmitting sonic waves.

Step 10: the ultrasonic or megasonic apparatus 4006 is turned on and the surface of the substrate 4010 is cleaned within a certain time according to the recipe.

Step 11: the ultrasonic or megasonic device 4006 is turned off and the ultrasonic or megasonic device 4006 is moved upward.

Step 12: a rinse chemistry or deionized water is supplied to the surface of the substrate 4010 to clean the substrate 4010.

Step 13: the substrate 4010 is dried.

Step 14: the rotation of the substrate 4010 is stopped, and the substrate 4010 is taken out from the cleaning chamber 4000.

The purpose of steps 2 to 3 is a bubble-less or bubble-free pre-wetting process. Since a vacuum environment is established around the surface of the substrate 4010 by evacuating a gas such as air or nitrogen gas in the pre-wetting chamber 4020 in step 2, the pre-wetting chemical liquid enters the through holes, grooves, and the like on the substrate 4010 without being blocked by bubbles in step 3.

Steps 7 to 11 may be repeated for at least one cycle. At least one chemical solution, such as SC1 (a mixture of ammonium hydroxide, hydrogen peroxide, and water), ozone water, ammonia water, and the like, may be used in this cleaning cycle.

In the cleaning steps of steps 6 to 12, the rotation speed of the substrate 4010 may be set at 10RPM to 1500RPM according to different time periods and controlled by a programmable recipe.

Fig.5 discloses a substrate cleaning apparatus according to another embodiment of the present invention. The apparatus is capable of pre-treating the substrate prior to a subsequent ultrasonic or megasonic cleaning process to obtain a bubble-free or bubble-free substrate surface. The apparatus combines a pre-wetting function with a cleaning function in a cleaning chamber 5000, wherein the substrate is pre-treated to obtain a bubble-less or bubble-free pre-wetted surface and then cleaned by a subsequent ultrasonic or megasonic cleaning process. Fig.5 discloses a wash chamber 5000. The cleaning chamber 5000 includes a cleaning cup housing 5001, a vacuum port 5018 connected to a vacuum pump to create a vacuum environment in the cleaning chamber 5000, a rotary actuator 5003, a substrate holder 5002, a blower filter unit 5015 generating a downward gas flow, at least one exhaust port 5017, a first stopper 5047 for the exhaust port 5017 and a second stopper 5045 for the blower filter unit 5015, a swing arm 5005 mounted with an ultrasonic or megasonic device 5006, a plurality of nozzle arms 5008, each nozzle arm 5008 being mounted with at least one nozzle 5009 to provide a chemical liquid or mist for pre-wetting, a chemical liquid or mist for cleaning, or a dry gas to the surface of the substrate 5010. When the vacuum port 5018 begins to create a vacuum pressure in the cleaning chamber 5000 during the pretreatment process, the blower filter unit 5015 and the exhaust port 5017 stop creating a downward gas flow over the surface of the substrate 5010. The second stopper 5045 is closed to isolate the blower filter unit 5015 from the cleaning chamber 5000 while the first stopper 5047 is closed to isolate the exhaust port 5017 from the cleaning chamber 5000, thereby establishing a vacuum environment in the cleaning chamber 5000. During subsequent cleaning, blower filter unit 5015 and exhaust 5017 are opened to create a downward flow of air.

According to another embodiment of the present invention, a substrate cleaning method is provided, including:

step 1: the substrate 5010 is transferred into the cleaning chamber 5000, and the substrate 5010 is held by the substrate holder 5002.

Step 2: the door of the cleaning chamber 5000 is closed, the blower filter unit 5015 and the exhaust 5017 are closed, the first catch 5047 and the second catch 5045 are closed, and a vacuum is initially drawn through the vacuum port 5018 into the cleaning chamber 5000 to establish a vacuum environment within the cleaning chamber 5000 at a set time. The degree of vacuum in the cleaning chamber 5000 was set at 25Torr or more.

And step 3: after the vacuum environment is formed, the substrate 5010 is driven to rotate at a set low rotation speed of 10RPM to 1000 RPM.

And 4, step 4: the pre-wetting showerhead is rotated to a position above the surface of the substrate 5010 to supply a pre-wetting chemical solution or chemical mist to the surface of the substrate 5010.

And 5: the vacuum pressure in the cleaning chamber 5000 is released and the blower filter unit 5015, exhaust port 5017, first stopper 5047 and second stopper 5045 are opened to create a downward flow of gas over the base 5010.

Step 6: the nozzle arm is swung to a position above the surface of the substrate 5010 to supply the cleaning liquid to the surface of the substrate 5010. A variety of chemical solutions may be used in this step.

And 7: a cleaning fluid is provided to the surface of the substrate 5010 for use in an ultrasonic or megasonic cleaning process.

And 8: the ultrasonic or megasonic device 5006 is moved downward to a height above the surface of the substrate 5010 and the gap between the ultrasonic or megasonic device 5006 and the surface of the substrate 5010 is filled with a cleaning fluid as a medium for transmitting sound waves.

And step 9: the ultrasonic or megasonic device 5006 is turned on and the surface of the substrate 5010 is cleaned within a certain time according to the recipe.

Step 10: the ultrasonic or megasonic device 5006 is turned off and the ultrasonic or megasonic device 5006 is moved upward.

Step 11: the substrate 5010 is cleaned by providing a rinse chemistry or deionized water to the surface of the substrate 5010.

Step 12: the substrate 5010 is dried.

Step 13: the rotation of the substrate 5010 is stopped, and the substrate 5010 is taken out from the cleaning chamber 5000.

The purpose of steps 2 to 4 is a bubble-less or bubble-free pre-wetting process. Since a vacuum environment is established around the surface of the substrate 5010 by evacuating a gas such as air or nitrogen in the cleaning chamber 5000 in step 2, the pre-wetting chemical liquid enters the through holes and grooves etc. on the substrate 5010 without being blocked by bubbles in step 4.

Steps 6 to 10 may be repeated for at least one cycle. At least one chemical solution, such as SC1 (a mixture of ammonium hydroxide, hydrogen peroxide, and water), ozone water, ammonia water, and the like, may be used in this cleaning cycle.

In the cleaning steps of step 5to step 11, the rotation speed of the substrate 5010 may be set at 10RPM to 1500RPM according to different time periods and controlled by a programmable recipe.

Fig.6A to 6B disclose a substrate cleaning apparatus according to yet another embodiment of the present invention. The apparatus is capable of pre-treating the substrate prior to a subsequent ultrasonic or megasonic cleaning process to obtain a bubble-free or bubble-free substrate surface. The apparatus includes a pre-wetting chamber 6020 and a washing chamber 6000. The substrate is pre-treated in the pre-wetting chamber 6020 to obtain a bubble-less or bubble-free pre-wetted surface, and then transferred to the cleaning chamber 6000 for a subsequent ultrasonic or megasonic cleaning process. Fig.6A discloses a pre-wetting chamber 6020. The pre-wetting chamber 6020 comprises: a vaporization unit 6030 configured to convert the chemical solution 6031 in a pre-wetting liquid state into gas-phase molecules; a rotation driving device 6024 configured to drive the rotation of the substrate 6010; at least one showerhead 6023 configured to be connected to the vaporizing unit 6030 and provide vaporized liquid molecules to a surface of the substrate 6010 to form a bubble-less or bubble-free pre-wetting chemical layer on the substrate 6010; a substrate holder 6021 configured to hold the substrate 6010 in the pre-wetting chamber 6020. In one embodiment, a plurality of shower heads 6023 are used to uniformly distribute the vaporized liquid molecules over the surface of substrate 6010. The vaporization unit 6030 is used to convert the pre-wetting chemical solution 6031 in a liquid phase into gas phase molecules. In one embodiment, the vaporization unit 6030 converts the pre-wetting chemical solution 6031 into gas-phase molecules by a sonic wave generation method. When the chemical liquid vapor is formed using the acoustic wave generating method, the chemical liquid vapor is heated to a temperature higher than the substrate 6010. Alternatively, the substrate 6010 is cooled to a temperature lower than the chemical liquid vapor. In another embodiment, the vaporization unit 6030 converts the pre-wetting chemical solution 6031 into gas-phase molecules by heating. The vaporized liquid molecules may also be carried by a medium gas such as nitrogen, air, ozone, ammonia, hydrogen, or helium. The carrier gas may be an inert gas used only for vaporized liquid molecule entrainment, or may be a reactive gas to assist the vaporized liquid molecules for substrate surface oxidation or passivation.

The vaporized liquid molecules are more easily transported from the vapor atmosphere in a large volume to the patterned structures such as trenches and vias on the substrate 6010. After the vaporized liquid molecules are distributed on the surface of the substrate 8010, the vaporized liquid molecules are condensed on the surface of the substrate 8010 to form a thin layer 8020 of pre-wetting liquid molecules, and the liquid molecules are formed layer by layer from bottom to top in the through holes and the grooves of the substrate 8010, as shown in fig.8A to 8B. However, if a part of the surface of the substrate is not well wetted, such a bottom-up liquid layer formation will be affected, and the liquid layer will break at the part of the substrate surface that is not well wetted due to surface tension. In one embodiment, the vaporizing unit 6030 converts a pre-wetting chemical solution containing a liquid phase of a surfactant or additive into vaporized mixed liquid molecules containing surfactant or additive molecules. The vaporized mixed liquid molecules containing surfactant or additive molecules can increase the wettability of the liquid chemical solution on the substrate surface, so that the liquid chemical solution can fill up the pattern structures such as through holes, grooves and the like on the substrate 6010 from bottom to top without bubble blockage. Ethylene Diamine Tetraacetic Acid (EDTA), tetra-carboxy ethylene diamine tetrapropionic acid (EDTP) acid or salt containing carboxyl groups and the like are doped in a liquid chemical solution as a surfactant to improve the wettability of the chemical solution. In another embodiment, the vaporization unit 6030 converts a pre-wetting chemical solution containing a liquid phase of a chemical for oxidizing the surface of the substrate 6010 from hydrophobicity to hydrophilicity into vaporized mixed liquid molecules. The vaporized mixed liquid molecules can increase the wettability of the liquid chemical solution on the surface of the substrate, so that the liquid chemical solution can fill pattern structures such as through holes, grooves and the like on the substrate 6010 from bottom to top without bubble blockage. Hydrophobic surface materials such as silicon or polysilicon layers are oxidized to hydrophilic silicon oxide layers using chemicals such as ozone solutions or SC1 solutions (ammonium hydroxide, hydrogen peroxide, water mixtures).

Fig.6B discloses a wash chamber 6000. The cleaning chamber 6000 includes: a cleaning cup cover 6001, a rotary actuator 6003, a substrate support 6002, a fan filter unit 6015, at least one exhaust port 6017, a swing arm 6005 having an ultrasonic or megasonic device 6006 mounted thereon, a plurality of nozzle arms 6008, each nozzle arm 6008 having at least one nozzle 6009 for supplying a chemical solution or a chemical mist or a dry gas for cleaning to the surface of the substrate 6010.

According to an embodiment of the present invention, a substrate cleaning method is provided, including:

step 1: the substrate 6010 is transferred into the pre-wetting chamber 6020, and the substrate 6010 is held by a substrate holder 6021.

Step 2: the pre-wetting chemical solution is supplied to a vaporization unit 6030 to produce vaporized liquid molecules.

And step 3: the door of the pre-wetting chamber 6020 is closed, the substrate 6010 is driven to rotate, and the vaporized liquid molecules are supplied to the surface of the substrate 6010 through the showerhead 6023 to perform the pre-wetting process.

And 4, step 4: the substrate 6010 is transferred from the pre-wetting chamber 6020 to the cleaning chamber 6000, and the substrate 6010 is held by a substrate holder 6002 in the cleaning chamber 6000.

And 5: the substrate 6010 is driven to rotate at a set low rotation speed, 10RPM to 1000 RPM.

Step 6: the nozzle arm 6008 is swung to a position above the surface of the substrate 6010 to supply a cleaning liquid to the surface of the substrate 6010. A variety of chemical solutions may be used in this step.

And 7: a cleaning fluid is supplied to the surface of the substrate 6010 for use in an ultrasonic or megasonic cleaning process.

And 8: the ultrasonic or megasonic device 6006 is moved down to a certain height from the surface of the substrate 6010, and a cleaning liquid is filled in a gap between the ultrasonic or megasonic device 6006 and the surface of the substrate 6010 as a medium for transmitting the sonic waves.

And step 9: the ultrasonic or megasonic apparatus 6006 is turned on and the surface of the substrate 6010 is cleaned according to the recipe for a certain period of time.

Step 10: the ultrasonic or megasonic device 6006 is turned off and the ultrasonic or megasonic device 6006 is moved upward.

Step 11: a rinsing chemical or deionized water is supplied to the surface of the substrate 6010 to clean the substrate 6010.

Step 12: the substrate 6010 is dried.

Step 13: the rotation of the substrate 6010 is stopped, and the substrate 6010 is taken out of the cleaning chamber 6000.

The purpose of steps 2 to 3 is a bubble-less or bubble-free pre-wetting process. The vaporized liquid molecules are distributed on the surface of the substrate 6010, the vaporized liquid molecules are condensed on the surface of the substrate 6010 to form a thin layer of pre-wetting liquid molecules, and the liquid molecules are formed in the through holes and the grooves of the substrate 6010 layer by layer from bottom to top.

Steps 7 to 10 may be repeated for at least one cycle. At least one chemical solution, such as SC1 (a mixture of ammonium hydroxide, hydrogen peroxide, and water), ozone water, ammonia water, and the like, may be used in this cleaning cycle.

In the cleaning steps of steps 6 to 11, the rotation speed of the substrate 6010 may be set at 10RPM to 1500RPM according to different time periods and controlled by a programmable recipe.

FIG.7 discloses a substrate cleaning apparatus according to one embodiment of the invention. The apparatus is capable of pre-treating the substrate prior to a subsequent ultrasonic or megasonic cleaning process to obtain a bubble-free or bubble-free substrate surface. The apparatus combines the pre-wetting function with the cleaning function in one cleaning chamber 7000, where the substrate is pre-treated to obtain a bubble-less or bubble-free pre-wetted surface and then cleaned by a subsequent ultrasonic or megasonic cleaning process. FIG.7 discloses wash chamber 7000. Cleaning chamber 7000 includes: a cleaning cup housing 7001, a rotary actuator 7003, a substrate support 7002, a fan filter unit 7015, at least one exhaust port 7017, a swing arm 7005 mounted with an ultrasonic or megasonic device 7006, a vaporizing unit 7030 for converting a pre-wetting liquid chemical solution 7031 into gas phase molecules, a plurality of nozzle arms 7008, wherein each nozzle arm 7008 is mounted with at least one spray head 7023 and at least one spray nozzle 7009, the spray head 7023 is connected to the vaporizing unit 7030 to provide vaporized liquid molecules to a substrate 7010 surface to form a bubble-less or bubble-free pre-wetting chemical solution layer on the substrate 7010, and the spray nozzles 7009 are used to provide a cleaning chemical solution or chemical mist and a drying gas to the substrate 7010 surface. In one embodiment, a plurality of spray heads 7023 are used to distribute the vaporized liquid molecules evenly over the surface of the substrate 7010. Vaporization unit 7030 is used to convert pre-wetting chemical solution 7031 in the liquid phase to molecules in the gas phase. In one embodiment, vaporizing unit 7030 converts pre-wetting chemical solution 7031 into gas phase molecules by a sonic generating method. In another embodiment, vaporizing unit 7030 converts pre-wetting chemical solution 7031 into gas phase molecules by heating. The vaporized liquid molecules may also be carried by a medium gas such as nitrogen, air, ozone, ammonia, hydrogen, or helium. The carrier gas may be an inert gas used only for vaporized liquid molecule entrainment, or may be a reactive gas to assist in vaporizing liquid molecules for surface oxidation or passivation of the substrate 7010.

The vaporized liquid molecules are more easily transported from the vapor environment in large quantities into the patterned structures such as trenches and vias on the substrate 7010. After the vaporized liquid molecules are distributed on the surface of the substrate 7010, the vaporized liquid molecules condense on the surface of the substrate 7010 to form a thin layer 8020 of pre-wetting liquid molecules, which are formed layer by layer from bottom to top in the through holes and trenches of the substrate 7010, as shown in fig.8A to 8B. However, if a part of the surface of the substrate 7010 is not well wetted, such bottom-up liquid layer formation is affected, and the liquid layer is broken at a place on the surface of the substrate where it is not well wetted due to surface tension. In one embodiment, vaporizing unit 7030 converts a pre-wetting chemical solution of a liquid phase containing a surfactant or additive into vaporized mixed liquid molecules containing surfactant or additive molecules. The vaporized mixed liquid molecules containing surfactant or additive molecules can increase the wettability of the liquid chemical solution on the substrate surface, so that the liquid chemical solution can fill up the pattern structures such as through holes, grooves, etc. on the substrate 7010 from bottom to top without bubble blockage. Ethylene Diamine Tetraacetic Acid (EDTA), tetra-carboxy ethylene diamine tetrapropionic acid (EDTP) acid or salt containing carboxyl groups and the like are doped in a liquid chemical solution as a surfactant to improve the wettability of the chemical solution. In another embodiment, the vaporization unit 7030 converts a pre-wetting chemical solution containing a liquid phase of a chemical for oxidizing the surface of the substrate 7010 from hydrophobicity to hydrophilicity into vaporized mixed liquid molecules. The vaporized mixed liquid molecules can increase the wettability of the liquid chemical solution on the surface of the substrate, so that the liquid chemical solution can fill up the pattern structures such as through holes, grooves and the like on the substrate 7010 from bottom to top without bubble blockage. Hydrophobic surface materials such as silicon or polysilicon layers are oxidized to hydrophilic silicon oxide layers using chemicals such as ozone solutions or SC1 solutions (ammonium hydroxide, hydrogen peroxide, water mixtures).

According to another embodiment of the present invention, a substrate cleaning method is provided, including:

step 1: substrate 7010 is transferred to wash chamber 7000 and substrate 7010 is held by substrate holder 7002.

Step 2: the substrate 7010 is driven to rotate at a set low rotation speed, 10RPM to 1000 RPM.

And step 3: the pre-wetting chemical solution is supplied to vaporization unit 7030 to produce vaporized liquid molecules.

And 4, step 4: the nozzle arm 7008 is swung to a position above the surface of the substrate 7010, and vaporized liquid molecules are supplied to the surface of the substrate 7010 through the shower head 7023 to perform a pre-wetting process.

And 5: a cleaning fluid is provided to the surface of the substrate 7010 using a nozzle 7009. A variety of chemical solutions may be used in this step.

Step 6: a cleaning fluid is provided to the surface of the substrate 7010 for use in an ultrasonic or megasonic cleaning process.

And 7: the ultrasonic or megasonic device 7006 is moved downward to a certain height from the surface of the substrate 7010, and a cleaning solution 7070 is filled in the gap between the ultrasonic or megasonic device 7006 and the surface of the substrate 7010 as a medium for transmitting the sonic waves.

And 8: the ultrasonic or megasonic apparatus 7006 is turned on and the surface of the substrate 7010 is cleaned according to the recipe for a certain period of time.

And step 9: the ultrasonic or megasonic device 7006 is turned off and the ultrasonic or megasonic device 7006 is moved upward.

Step 10: a rinse chemical or deionized water is supplied to the surface of the substrate 7010 to clean the substrate 7010.

Step 11: the substrate 7010 is dried.

Step 12: rotation of the substrate 7010 is stopped and the substrate 7010 is removed from the cleaning chamber 7000.

The purpose of steps 2 to 4 is a bubble-less or bubble-free pre-wetting process. The vaporized liquid molecules are distributed on the surface of the substrate 7010, and the vaporized liquid molecules are condensed on the surface of the substrate 7010 to form a thin layer of pre-wetting liquid molecules, which are formed layer by layer from bottom to top in the through holes and the grooves of the substrate 7010.

Steps 6 to 9 may be repeated for at least one cycle. At least one chemical solution, such as SC1 (a mixture of ammonium hydroxide, hydrogen peroxide, and water), ozone water, ammonia water, and the like, may be used in this cleaning cycle.

In the cleaning step of steps 5to 10, the rotation speed of the substrate 7010 may be set at 10RPM to 1500RPM according to different time periods and controlled by a programmable recipe.

Fig.9A to 9B illustrate a substrate 9010 having a pattern 9060 with some scum or burrs 9061 in a recessed area of the substrate 9010. During the pre-wetting process and subsequent cleaning process, air bubbles 9062 will accumulate around these areas with scum or burrs 9061, which will result in possible damage to the patterned structure 9060 during ultrasonic or megasonic cleaning as shown in fig. 2A. Therefore, preferably, before performing the low-bubble or bubble-free pre-wetting process, a pre-treatment unit is preferably used to remove the scum and burrs 9061 to obtain a smooth surface of the pattern structure 9060, as shown in fig. 9C. In this case, no air bubbles may be attached to the surface of the dross or burr in the pre-wetting process, as shown in fig. 9D. In one embodiment, the scum 9061 on the pattern structure 9060 is removed by using high-energy plasma to obtain a smooth surface of the pattern structure. Then, the substrate 9010 is transferred to the pre-wetting chamber to perform a bubble-less or bubble-free pre-wetting process, and transferred to the cleaning chamber to perform an ultrasonic or megasonic cleaning process.