US20240207999A1

US20240207999A1 - Substrate rotation processing device and substrate polishing device

Info

Publication number: US20240207999A1
Application number: US18/518,570
Authority: US
Inventors: Hiroki Miyamoto
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2022-12-21
Filing date: 2023-11-23
Publication date: 2024-06-27

Abstract

A substrate drying device as a substrate rotation processing device includes: a substrate holding mechanism, holding a substrate horizontally; a rotating cover, configured to surround the substrate and having a side wall part surrounding the substrate and a bottom surface part in an inner side of the side wall part; a rotation mechanism, rotating the substrate held by the substrate holding mechanism and the rotating cover; and a gas supply nozzle, supplying gas with respect to a back surface of the substrate held by the substrate holding mechanism through the bottom surface part of the rotating cover. Multiple discharge holes for discharging gas supplied from the gas supply nozzle are formed on the bottom surface part of the rotating cover. The discharge holes have inclined surfaces formed inclined with respect to a rotating surface of the rotating cover.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefits of Japan application no. 2022-204284, filed on Dec. 21, 2022. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The disclosure relates to a substrate rotation processing device that performs cleaning and drying processes while rotating a semiconductor substrate or the like.

Description of Related Art

In the manufacturing process of semiconductor devices, substrate polishing devices that perform a polishing process on surfaces such as semiconductor substrates are widely used. The polished substrates are sent to a substrate cleaning device, where a substrate cleaning process is performed to remove unwanted (residues) defects on the substrate and a substrate drying process is performed to dry the cleaned substrate. The substrate cleaning device includes a substrate holding mechanism that holds the substrate, a motor that rotates the substrate holding mechanism, a fixed cover configured around the substrate, and a nozzle that supplies cleaning liquid (pure water) to the substrate surface. When cleaning the substrate, cleaning liquid is supplied to the substrate surface while rotating the substrate at low speed; and when drying the substrate, the substrate is rotated at high speed to remove the cleaning liquid from the substrate surface. The cleaning liquid shaken off from the substrate surface is collected in the fixed cover.
When the substrate is rotated at high speed during drying, a swirling flow is generated
on the inner side of the fixed cover, the mist of the cleaning liquid removed from the substrate may adhere to the surface of the substrate due to the swirling flow, resulting in watermarks on the surface of the substrate. To suppress such watermarks, a method (Rotogoni drying) of drying the substrate by moving these two nozzles along the radial direction of the substrate while supplying IPA vapor (a mixture of isopropyl alcohol and nitrogen gas) and pure water from two parallel nozzles to the substrate surface is used.
Further, Patent Document 1 (Japanese Patent Application Laid-Open (JP-A) No. 2009-117794) discloses a substrate cleaning device in which a rotating cover that rotates at substantially the same speed as the substrate is configured around the substrate. As a result, the relative speed between the substrate and the rotating cover becomes almost zero, and by suppressing the formation of the swirling flow of gas on the inner side of the rotating cover, it is possible to prevent the mist of the cleaning liquid from adhering to the substrate.
In such a substrate cleaning device, gas (nitrogen gas) is discharged on the back surface of the substrate for substrate drying, and the drying gas is exhausted downward through an opening formed on the outer circumference part of the rotating cover. However, due to the high-speed rotation of the substrate and rotating cover, a flow to the upper direction of the substrate occurs, as a result, the drying gas discharged to the back surface of the substrate may not be sufficiently exhausted and may remain below the substrate. In that case, there is a risk that the quality of the substrate after the drying process may deteriorate due to residues (defects) and moisture adhering to the back surface of the substrate.
In view of the above, the disclosure was made for the purpose of providing a substrate rotation processing device and a substrate polishing device using such a substrate rotation processing device, which can effectively suppress the retention of drying gas with a simple configuration.

SUMMARY

The substrate rotation processing device according to one aspect of the disclosure
includes: a substrate holding mechanism, holding a substrate horizontally; a rotating cover, configured to surround the substrate and having a side wall part surrounding the substrate and a bottom surface part in an inner side of the side wall part; a rotation mechanism, rotating the substrate held by the substrate holding mechanism and the rotating cover; and a gas supply nozzle, supplying gas with respect to a back surface of the substrate held by the substrate holding mechanism through the bottom surface part of the rotating cover. Multiple discharge holes for discharging gas supplied from the gas supply nozzle are formed on the bottom surface part of the rotating cover, and the discharge holes have inclined surfaces formed inclined with respect to a rotating surface of the rotating cover.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view schematically showing the configuration of the substrate polishing device according to one embodiment of the disclosure.

FIG. 2 is a schematic cross-sectional view showing the configuration of the substrate drying device, which is an example of the substrate rotation processing device.

FIG. 3 is a schematic cross-sectional view showing the state in which the substrate is lifted in the substrate drying device of FIG. 2 .

FIG. 4A to FIG. 4C are diagrams showing the configuration of an example of the rotating cover attached to the substrate drying device, in which FIG. 4A is a perspective view, FIG. 4B is a plan view, and FIG. 4C is a partial cross-sectional view.

FIG. 5A to FIG. 5C are diagrams showing the configuration of another example of the rotating cover, in which FIG. 5A is a perspective view, FIG. 5B is a plan view, and FIG. 5C is a partial cross-sectional view.

FIG. 6A to FIG. 6C are diagrams showing the configuration of yet another example of the rotating cover, in which FIG. 6A is a perspective view, FIG. 6B is a plan view, and FIG. 6C is a side view.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a substrate polishing device including a substrate rotation processing device (substrate drying device) according to one embodiment of the disclosure will be described with reference to the drawings. It should be noted that the same or corresponding components are given the same reference numerals and redundant explanations will be omitted.
In the substrate rotation processing device in one aspect of the disclosure, the discharge holes are circular or rectangular when the rotating cover is viewed from above. Further, the bottom surface part of the rotating cover is provided with multiple impellers formed inclined with respect to the rotating surface of the rotating cover, and the discharge holes are formed between two adjacent impellers. In the substrate rotation processing device in one aspect of the disclosure, a cleaning liquid supply nozzle that supplies cleaning liquid to the substrate is further included.
A substrate polishing device according to one aspect of the disclosure includes the substrate rotation processing device described above, and the substrate rotation processing device is a substrate drying device that performs a drying process on the substrate after the polishing process.
According to the disclosure, the openings formed in the circumferential direction of the rotating cover strengthen the airflow downward from the rotating cover, thereby effectively suppressing the retention of drying gas with a simple configuration.
FIG. 1 is a plan view showing the overall configuration of the substrate polishing device. The substrate polishing device 10 is divided into a loading/unloading part 12, a polishing part 13, and a cleaning/drying part 14, which are provided in the interior of a rectangular housing 11. Further, the substrate polishing device 10 includes a control device 15 that controls operations such as substrate transporting, polishing, and cleaning.
The loading/unloading part 12 includes multiple front loading parts 20, a traveling mechanism 21, and a transport robot 22. Substrate cassettes for stocking a large number of substrates (wafers) W are placed in the front loading parts 20. The transport robot 22 includes two hands on top and on bottom, and by moving on the traveling mechanism 21, the substrate W in the substrate cassette placed in the front loading part 20 is taken out and transported to the polishing part 13, and the processed substrate transported from the cleaning part 14 is returned to the substrate cassette.
The polishing part 13 is an area for polishing (planarizing) the substrate, and is provided with multiple polishing units 13A to 13D, which are arranged along the longitudinal direction of the substrate processing device. Each of the polishing units includes a top ring, a liquid supply nozzle, a dresser, and an atomizer. The top ring polishes the substrate W on the polishing table while pressing the same against a polishing pad; the liquid supply nozzle supplies liquid such as polishing liquid or pure water to the polishing pad; the dresser dresses the polishing surface of the polishing pad; and the atomizer sprays a mixed fluid of liquid and gas or a mist of liquid onto the polishing surface to wash away polishing debris and abrasive grains remaining on the polishing surface. The first and second linear transporters 16 and 17 are provided between the polishing part 13 and the cleaning part 14 as transport mechanisms for transporting the substrate W.
The cleaning part 14 includes a first substrate cleaning device 23, a second substrate cleaning device 24, a substrate drying device 30, and transport robots 25 and 26 provided therebetween for transporting substrate. The substrate W that has undergone the polishing process in the polishing unit is scrubbed and cleaned (primary cleaning) by a pair of roll sponges in the first substrate cleaning device 23. Next, in the second substrate cleaning device 24, the substrate W is further scrubbed and cleaned (finishing cleaning) using a pair of roll sponges. The cleaned substrate is carried from the second substrate cleaning device 24 to the substrate drying device 30, which serves as the substrate rotation processing device, for Rotogoni drying. The dried substrate W is taken out by the transport robot 22 and returned from the substrate drying device 30 to the substrate cassette placed on the front loading part 20.
The control program for controlling the operation of the substrate polishing device 10 may be installed in advance in a computer configuring the control device 15; alternatively, it may be stored in a storage medium such as a CD-ROM or DVD-ROM; furthermore, it may be installed in the control device 15 through the Internet.
As shown in FIG. 2 , the substrate drying device 30 includes a substrate holding mechanism 31, a motor (rotation mechanism) 32, a rotating cover 40, and a front nozzle 34. The substrate holding mechanism 31 holds the substrate W horizontally, the motor 32 rotates the substrate W around the central axis thereof through the substrate holding mechanism 31, the rotating cover 40 is configured around the substrate W, and the front nozzle 34 supplies pure water as a cleaning liquid to the surface (front surface) of the substrate W. As the cleaning liquid, a chemical solution may be used instead of pure water.
The substrate holding mechanism 31 includes multiple chucks 35 that grip the peripheral part of the substrate W, a circular stage 36 to which these chucks 35 are fixed, and a hollow support shaft 37 that supports this stage 36. The rotating cover 40 is fixed on the stage 36, and the stage 36 and the rotating cover 40 are configured coaxially. Further, the substrate W held by the chucks 35 and the rotating cover 40 are located coaxially.
The motor 32 is connected to the outer circulation surface of the support shaft 37, and the torque of the motor 32 is transmitted to the support shaft 37. As a result, the stage 36 and the rotating cover 40 rotate, and the substrate W held by the chucks 35 also rotates.
At least three push rods 38 and an actuator 39 for vertically moving these push rods 38 are configured below the stage 36. Multiple through holes 36 a and 40 a are formed on the stage 36 and the rotating cover 40 corresponding to the positions of the push rods 38. After the drying process, as shown in FIG. 3 , the push rods 38 are raised by the actuator 39, and the push rods 38 pass through the through holes 36 a and 40 a and lift the substrate W. Afterwards, the dried substrate W is transported by the hands of a transport robot that is not shown in the figure.
Referring to FIG. 2 , a back nozzle 52 connected to a cleaning liquid supply source 50 and a gas nozzle 53 connected to a dry gas supply source 51 are configured in the interior of the support shaft 37. The cleaning liquid supply source 50 stores pure water as the cleaning liquid, and the pure water is supplied to the back surface of the substrate W through the back nozzle 52. Further, the dry gas supply source 51 stores N2 gas or dry air as the dry gas, and the dry gas is supplied to the back surface of the substrate W through the gas nozzle 53.
The front nozzle 34 is connected to a pure water supply source (cleaning liquid supply source) that is not shown in the figure and is configured facing the center of the substrate W, so that pure water is supplied to the center of the surface of the substrate W. Further, two nozzles 55 and 56 are configured in parallel above the substrate W to perform Rotogoni drying. In the figure, the nozzle 55 on the left side supplies IPA vapor (a mixed gas of isopropyl alcohol and N2 gas) to the surface of the substrate W, and the nozzle 56 on the right side supplies pure water to prevent the surface of the substrate W from drying out. These nozzles 55 and 56 are movably configured along the radial direction of the substrate W.
Multiple discharge holes 42 (see FIG. 4A to FIG. 4C) are formed on the bottom surface of the rotating cover 40 at the peripheral part. As shown in FIG. 4A to FIG. 4C, the discharge holes 42 are substantially circular openings formed along the circumferential direction of the rotating cover 40 and inclined radially outward toward the lower opening. Referring to FIG. 2 , the cleaning liquid (pure water) supplied from the front nozzle 34 and the back nozzle 52 and the pure water supplied from the nozzle 56 are discharged through the discharge holes 42, along with the gas from the gas nozzle 53, the IPA vapor from the nozzle 55, and ambient atmosphere (usually air), to the outside of the rotating cover 40.
A discharge passage 57 and an exhaust passage 58 are provided below the discharge holes 42. Both discharge passage 57 and exhaust passage 58 are formed in a ring shape, and the discharge passage 57 is located outside of the exhaust passage 58 in the radial direction. According to such a configuration, the liquid and gas discharged from the discharge holes 42 are separated by centrifugal force, and the liquid flows into the discharge passage 57 and the gas flows into the exhaust passage 58. The exhaust passage 58 is connected to a suction source (e.g., a vacuum pump) 60.
A disk-shaped fixed plate 61 is configured below the stage 36 with a small gap therebetween, which prevents the surrounding gas from being disturbed by the rotating stage 36. Further, a cylindrical skirt 62 extending downward is configured at the peripheral part of the stage 36 to prevent the liquid discharged from the discharge holes 42 from scattering around.
As shown in FIG. 4A, the rotating cover 40 includes a side wall part 43 formed to surround the substrate W held by the substrate holding mechanism 31 and a circular bottom surface part 45 on which multiple discharge holes 42 are formed. The upper end of the side wall part 43 of the rotating cover 40 is located above the substrate W. The diameter of the inner circumferential surface of the side wall part 43 (inner diameter of the rotating cover 40) is formed to gradually decrease toward the upper end of the side wall part 43. That is, the side wall part 43 of the rotating cover 40 is inclined inwardly in the radial direction as a whole, and the angle between the inner circumferential surface of the side wall part 43 and the horizontal plane is less than 90 degrees. In this embodiment, the inner circumferential surface of the rotating cover 40 has a cross-sectional shape (arc shape) configured by curves, but is not limited thereto, and may be configured, for example, by multiple straight lines (slope lines).
As shown in FIG. 4B, near the outer edge of the bottom surface part 45 of the rotating cover 40, multiple discharge holes 42 are formed along the circumferential direction of the rotating cover 40 These discharge holes 42 are formed so that the cleaning liquid (pure water) from the front nozzle 34 and the back nozzle 52, the pure water supplied from the nozzle 56, the gas from the gas nozzle 53, and the IPA vapor from the nozzle 55 are discharged to the outside.
As shown in FIG. 4C, each of the discharge holes 42 formed along the circumferential direction of the rotating cover 40 has an inclined surface 42 a (the surface shown in gray in FIG. 4B, with an inclination angle θ with respect to the vertical direction Z) formed inclined with respect to the bottom surface (rotating surface) of the rotating cover 40. Thus, as shown by the dotted line in FIG. 4A, as the rotating cover 40 rotates, a downflow that flows through the discharge holes 42 in the interior of the rotating cover 40 is formed. In this way, the gas supplied from the gas nozzle 53 is prevented from remaining in the interior of the rotating cover 40.
The operation of the substrate drying device 30 according to this embodiment will be described. First, when the substrate W is set on the chucks 35, the motor 32 rotates the stage 36 (substrate holding mechanism 31). This causes the substrate W and the rotating cover 40 to rotate. In this state, pure water is supplied from the front nozzle 34 and the back nozzle 52 to the surface (top surface) and the back surface (bottom surface) of the substrate W, and the entire surface of the substrate W is rinsed with the pure water. The pure water supplied to the substrate W spreads over the entire surface and the back surface of the substrate W by centrifugal force, thereby rinsing the entire substrate W. The pure water shaken off from the rotating substrate W is captured by the rotating cover 40 and flows into the discharge holes 42.
Here, since the rotating cover 40 and the substrate W are rotating at the same speed, when the pure water collides with the inner circumferential surface of the rotating cover 40, there is almost no chance of the pure water being scattered. In addition, since almost no swirling flow of gas is formed in the space between the rotating cover 40 and the substrate W, which rotate at the same speed, pure water droplets are not carried to the substrate W by swirling flow, and the formation of watermarks may be prevented.
Next, the supply of pure water from the front nozzle 34 and the back nozzle 52 is stopped, the front nozzle 34 is moved to a predetermined standby position away from the substrate W, and the two nozzles 55 and 56 are moved to the working position above the substrate W. Then, while rotating the substrate W at a low speed of 150 to 300 revolutions per minute, the IPA vapor from the nozzle 55 and the pure water from the nozzle 56 are supplied toward the surface of the substrate W. Then, the two nozzles 55 and 56 are simultaneously moved along the radial direction of the substrate W. In this way, the surface (top surface) of substrate W is dried.
After that, the two nozzles 55 and 56 are moved to a predetermined standby position, and the substrate W is rotated at a high speed of 1000 to 1500 revolutions per minute, and the pure water adhering to the back surface of the substrate W is shaken off. While the substrate W is rotating at a high speed, dry gas is sprayed from the gas nozzle 53 onto the back surface of the substrate W. In this way, the back surface of the substrate W is dried.
While the back surface of the substrate W is drying, when the dry gas supplied from the
gas nozzle 53 is sprayed onto the back surface of the substrate W, the dry gas gradually moves toward the side wall part 43 of the rotating cover 40 and is discharged through the discharge holes 42 to the outside of the rotating cover 40. However, since the substrate W is rotating at a high speed, a flow in the upper direction is generated, and a part of the dry gas blown onto the substrate W may remain in the interior of the rotating cover 40. As a result, there is a risk that the residue inside the rotating cover 40 may adhere to the back surface of the substrate W.
In the substrate drying device according to this embodiment, the discharge holes 42 formed on the rotating cover 40 is formed inclined with respect to the rotation direction of the rotating cover 40, and with this inclined surface 42 a, the flow in the upper direction in the discharge holes 42 in the interior of the rotating cover 40 is reduced. In this way, the gas supplied from the gas nozzle 53 is prevented from remaining in the interior of the rotating cover 40.
When the drying of the substrate W is completed, the supply of dry gas from the gas nozzle 53 is stopped. Then, as shown in FIG. 3 , the actuator 39 raises the substrate W until the substrate W is located above the rotating cover 40. The dried substrate W is taken out from the substrate holding mechanism 31 by the hands of a transport robot that is not shown in the figure.
In the above embodiment, the discharge holes 42 are formed along the circumferential direction of the rotating cover 40 with almost no gaps, but the number and size of the discharge holes 42 are not limited to this embodiment and may be changed as appropriate.
In the above embodiment, the discharge holes 42 are formed to have a circular shape when viewed from above, but the shape of the discharge holes 42 is not limited to this embodiment. For example, in the example shown in FIG. 5A to FIG. 5C, multiple rectangular discharge holes 72 are formed in the rotating cover 70 along the circumferential direction (rotation direction of the rotating cover), and each of the discharge holes 72 has an inclined surface 72 a (the surface shown in gray in FIG. 5B, with an inclination angle θ with respect to the vertical direction Z) formed inclined with respect to the bottom surface (rotating surface) of the rotating cover 70. With this configuration, the inclined surfaces 72 a formed inclined with respect to the discharge holes 72 form a downflow that flows through the discharge holes 72 in the interior of the rotating cover 70, and gas supplied from the gas nozzle 53 is also prevented from remaining in the interior of the rotating cover 70.
In the example shown in FIG. 6A to FIG. 6C, multiple impellers 81 having top parts 81 a is formed in the rotating cover 80 along the circumferential direction (rotation direction of the rotating cover), and each of the impellers 81 is formed inclined with respect to the bottom surface (rotating surface) of the rotating cover 80 and configures an inclined surface (the surface whose upper surface is shown in gray in FIG. 6B, with an inclination angle θ with respect to the vertical direction Z). The discharge hole 82 is formed by two adjacent impellers 81, and each of the discharge holes 82 has an inclined surface (impeller 81) formed inclined with respect to the circumferential direction of the rotating cover 80. These impellers 81 form a downflow that flows through the discharge holes 82 in the interior of the rotating cover 80, and gas supplied from the gas nozzle 53 is prevented from remaining in the interior of the rotating cover 80. It should be noted that in FIG. 6C, since the direction of the inclined surfaces is opposite to that in FIG. 4C and FIG. 5C, the rotation direction of the rotating cover 80 is also opposite to that in FIG. 4C and FIG. 5C.
Regarding the relationship between the inclination angle θ of the discharge holes 72 formed in the rotating cover 70 in FIG. 5C and the airflow, a simulation was performed by changing the inclination angle θ. A part of the airflow and the flow rate of the discharge holes 72, when the number of discharge holes 72 was 4 (equally spaced every 90 degrees), the inclination angle θ was 5 degrees (almost vertical), 30 degrees, 45 degrees, and 60 degrees, and the speed of the rotating cover 40 was about 1800 rpm, were calculated. The results are as follows.


Inclination angle	Air flow direction	Flow rate

5	degrees	Upward direction	0.93 [m³/min]
30	degrees	Upward direction	0.26 [m³/min]
45	degrees	Downward direction	0.67 [m³/min]
60	degrees	Downward direction	0.38 [m³/min]

The above simulation results show that the airflow was in the upward direction when the inclination angle θ was 5 degrees and almost vertical, but that the inclination angle reduced the upward airflow, resulting in a downward airflow (downflow) when the angle was 45 degrees and 60 degrees. When the inclination angle θ was increased to 60 degrees, the airflow was obstructed and the downflow flow rate was reduced compared to the case of 45 degrees.
From the above, by providing the inclination angle θ, it is possible to reduce the risk that a part of the dry gas sprayed onto the substrate W remains in the interior of the rotating cover. Further, from the viewpoint of effectively reducing the flow in the upward direction, the inclination angle θ is set to 30 degrees to 60 degrees, and from the viewpoint of obtaining the downflow, the inclination angle θ is set in the range of 40 degrees to 50 degrees.
The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the disclosure belongs to implement the disclosure. Various modifications of the above embodiments can be made by those skilled in the art, and the technical idea of the disclosure can be applied to other embodiments. The disclosure is not limited to the described embodiments and is to be construed in its broadest scope in accordance with the technical idea defined by the claims.

Claims

What is claimed is:

1. A substrate rotation processing device, comprising: a substrate holding mechanism, holding a substrate horizontally;

a rotating cover, configured to surround the substrate and having a side wall part surrounding the substrate and a bottom surface part in an inner side of the side wall part;

a rotation mechanism, rotating the substrate held by the substrate holding mechanism and the rotating cover; and

a gas supply nozzle, supplying gas with respect to a back surface of the substrate held by the substrate holding mechanism through the bottom surface part of the rotating cover,

wherein a plurality of discharge holes for discharging gas supplied from the gas supply nozzle are formed on the bottom surface part of the rotating cover, and the discharge holes have inclined surfaces formed inclined with respect to a rotating surface of the rotating cover.

2. The substrate rotation processing device according to claim 1, wherein the discharge holes are circular when the rotating cover is viewed from above.

3. The substrate rotation processing device according to claim 1, wherein the discharge holes are rectangular when the rotating cover is viewed from above.

4. The substrate rotation processing device according to claim 1, wherein the bottom surface part of the rotating cover is provided with a plurality of impellers formed inclined with respect to the rotating surface of the rotating cover, and the discharge holes are formed between two adjacent impellers.

5. The substrate rotation processing device according to claim 1, further comprising a cleaning liquid supply nozzle that supplies cleaning liquid to the substrate.

6. A substrate polishing device, comprising the substrate rotation processing device according to claim 1, wherein the substrate polishing device performs a polishing process on the substrate, and the substrate rotation processing device is a substrate drying device that performs a drying process on the substrate after the polishing process.