CN111266994A

CN111266994A - Cleaning device

Info

Publication number: CN111266994A
Application number: CN202010206588.1A
Authority: CN
Inventors: 郑凯铭
Original assignee: Yangtze Memory Technologies Co Ltd
Current assignee: Yangtze Memory Technologies Co Ltd
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2020-06-12

Abstract

The present invention relates to a cleaning device. The cleaning device includes: the first nozzle is used for spraying cleaning liquid towards a surface to be cleaned; and the second nozzle is used for spraying gas towards the surface to be cleaned, and the cleaning liquid and the gas are mixed to form a supercritical fluid so as to remove impurities remained on the surface to be cleaned. In one aspect of the invention, the cleaning efficiency of the cleaning device is improved; on the other hand, the cleaning ability of the cleaning device is improved. In addition, the gas released from the supercritical fluid can also effectively prevent the wafer from being corroded during the conveying process, thereby improving the quality of the wafer product.

Description

Cleaning device

Technical Field

The invention relates to the technical field of semiconductor manufacturing, in particular to a cleaning device.

Background

With the development of the planar flash memory, the manufacturing process of the semiconductor has been greatly improved. In recent years, however, the development of planar flash memories has met with various challenges: physical limits, existing development technology limits, and storage electron density limits, among others. In this context, to solve the difficulties encountered by flat flash memories and to pursue lower production costs of unit memory cells, various three-dimensional (3D) flash memory structures, such as 3D NOR (3D NOR) flash memory and 3D NAND (3D NAND) flash memory, have come into force.

The 3D NAND memory is based on the small volume and the large capacity, the design concept of the three-dimensional mode layer-by-layer stacking height integration of the storage units is adopted, the memory with high unit area storage density and high-efficiency storage unit performance is produced, and the mainstream process of the design and production of the emerging memory is formed.

In the manufacturing process of a semiconductor device such as a 3D NAND memory, Chemical Mechanical Polishing (CMP) is a crucial step. However, whether the surface of the polishing pad in the chemical mechanical polishing apparatus is clean or not is an important index for smoothly performing the chemical mechanical polishing process and evaluating the quality of the chemical mechanical polishing. However, the conventional method cannot effectively remove the impurities on the surface of the polishing pad, and the cleaning efficiency is low, so that the wafer is at risk of being scratched during the chemical mechanical polishing process, and the productivity of the chemical mechanical polishing apparatus is reduced.

Therefore, how to improve the cleaning quality of the polishing pad in the chemical mechanical polishing apparatus and improve the cleaning efficiency of the polishing pad is a technical problem to be solved.

Disclosure of Invention

The invention provides a cleaning device, which is used for solving the problem of poor cleaning efficiency of the existing cleaning method so as to improve the cleaning effect.

In order to solve the above problems, the present invention provides a cleaning device including:

the first nozzle is used for spraying cleaning liquid towards a surface to be cleaned;

and the second nozzle is used for spraying gas towards the surface to be cleaned, and the cleaning liquid and the gas are mixed to form a supercritical fluid so as to remove impurities remained on the surface to be cleaned.

Optionally, the first spout is disposed around an outer periphery of the second spout.

Optionally, a nozzle is included, the nozzle comprising:

a nozzle body;

the first channel is positioned inside the nozzle body and is used for being communicated with the first nozzle;

the second channel is positioned in the nozzle body and is used for being communicated with the second nozzle, and the second channel is nested in the first channel.

Optionally, the nozzle further comprises:

a first inlet at an end of the nozzle body facing away from the first spout for delivering the cleaning fluid to the first channel, the first inlet being disposed off-center of the nozzle body;

a second inlet at an end of the nozzle body facing away from the second nozzle orifice for delivering the gas to the second passageway, the second inlet being aligned with a center of the nozzle body.

Optionally, the first nozzle and the second nozzle are arranged in parallel, and the second nozzle is located on one side of the first nozzle.

Optionally, the method further includes:

and the first control valve is arranged outside the nozzle and used for adjusting the flow rate of the cleaning liquid transmitted to the first channel.

Optionally, the method further includes:

a second control valve installed outside the nozzle for adjusting a flow rate of the gas transmitted to the second passage.

Optionally, the method further includes:

a third control valve installed outside the nozzle for adjusting a pressure of the gas transmitted to the second passage.

Optionally, the first nozzle sprays the cleaning liquid along a direction perpendicular to the surface to be cleaned;

the second nozzle jets the gas in a direction inclined with respect to the surface to be cleaned.

Optionally, the cleaning solution is deionized water, and the gas is nitrogen or inert gas.

According to the cleaning device provided by the invention, the first nozzle for spraying the cleaning liquid and the second nozzle for spraying the gas are respectively arranged, so that the cleaning liquid and the gas are sprayed to form the supercritical fluid, and the surface to be cleaned is cleaned by using the supercritical fluid; on the other hand, the supercritical fluid has high solubility to the particles, so that impurities remained on the surface to be cleaned can be reduced, and the cleaning capability of the cleaning device is improved. In addition, the gas released from the supercritical fluid can also effectively prevent the wafer from being corroded during the conveying process, thereby improving the quality of the wafer product.

Drawings

FIG. 1 is a schematic view of the overall structure of a cleaning apparatus according to an embodiment of the present invention;

FIG. 2 is a bottom view of a nozzle in a cleaning device according to an embodiment of the present invention;

figure 3 is a side view of a nozzle in a cleaning device according to an embodiment of the present invention.

Detailed Description

The following describes in detail a specific embodiment of the cleaning device according to the present invention with reference to the accompanying drawings.

In the current chemical mechanical polishing apparatus, a cleaning liquid nozzle for cleaning the polishing pad is usually installed directly below the polishing arm. When the structure is adopted to clean the surface of the grinding pad before the wafer is ground, the cleaning liquid can only be sprayed on the surface of the grinding pad right below the cleaning liquid nozzle, on one hand, the cleaning area of the cleaning liquid sprayed once is limited, and therefore the cleaning efficiency of the grinding pad is reduced; on the other hand, although the polishing arm moves with the cleaning solution nozzle in a preset step length, the cleaning solution nozzle has a limited cleaning area for spraying cleaning solution once, so that the cleaning capability of the polishing pad is reduced. The reduction in cleaning efficiency of the polishing pad can prolong the down time of the cmp apparatus, thereby reducing the throughput of the cmp apparatus. The reduction of the cleaning capability of the grinding pad can cause the residue of particles on the surface of the grinding pad, and the subsequent chemical mechanical grinding process of the wafer is very easy to generate scratches on the surface of the wafer, thereby affecting the quality of the wafer product and even causing the rejection of the wafer in serious conditions.

In order to improve the cleaning performance of a semiconductor device such as a polishing pad, a cleaning apparatus is provided in the present embodiment, and fig. 1 is a schematic view of the overall structure of the cleaning apparatus according to the embodiment of the present invention. As shown in fig. 1, the cleaning device according to the present embodiment includes:

a first nozzle 11 for spraying a cleaning liquid towards a surface 101 to be cleaned;

and the second nozzle 12 is used for spraying gas towards the surface 101 to be cleaned, and the cleaning liquid and the gas are mixed to form a supercritical fluid so as to remove impurities remained on the surface 101 to be cleaned.

The supercritical state is a state in which the pressure and temperature of a substance exceed both its critical pressure and critical temperature; supercritical fluid refers to a fluid having both temperature and pressure above the critical point. The supercritical fluid in this embodiment refers to a mixed fluid including the cleaning liquid and the gas in a supercritical state.

Specifically, the surface 101 to be cleaned can be a surface on any semiconductor device for processing a wafer. In the present embodiment, the surface to be cleaned 101 is taken as a surface of the polishing pad 10 for carrying a wafer. The first nozzle 11 and the second nozzle 12 are disposed above the surface 101 to be cleaned in a direction perpendicular to the surface 101 to be cleaned (i.e., a Z-axis direction in fig. 1). The second nozzle 12 sprays the gas onto the surface 101 to be cleaned while the first nozzle 11 sprays the cleaning liquid onto the surface 101 to be cleaned, and the gas and the cleaning liquid fall onto the surface 101 to be cleaned after being mixed to form the supercritical fluid. The area of the surface to be cleaned 101 cleaned by the supercritical fluid in a single time is greatly increased, so that the cleaning efficiency of the surface to be cleaned is improved, the time for stopping and waiting of semiconductor equipment such as a chemical mechanical polishing device is shortened, and the capacity of the semiconductor equipment such as the chemical mechanical polishing device is improved. Moreover, due to the increase of the single cleaning area of the supercritical fluid, the residue of impurities such as particles on the surface to be cleaned is reduced, the cleaning capability of the cleaning device is improved, and the surface defects of the wafer are improved. Furthermore, the supercritical fluid has a solubility for particulate impurities such as silica that is much higher than the solubility in the cleaning solution, thereby helping to further reduce the residue of impurities on the surface to be cleaned. In addition, during the process of cleaning the surface to be cleaned 101, the gas released by the supercritical fluid can form a protective atmosphere around the surface to be cleaned 101, so that the wafer is prevented from being corroded during the conveying process.

In this embodiment, the specific type of the cleaning solution may be selected according to the type of the surface 101 to be cleaned, and may be, for example, but not limited to, deionized water. The specific type of the gas, and the flow rate and pressure of the gas sprayed from the second nozzle 12 may also be selected by those skilled in the art according to actual needs, for example, according to the specific type of the cleaning solution, which is not limited in this embodiment, as long as the sprayed gas and the sprayed deionized water form a supercritical fluid. The second nozzle 12 protrudes from the first nozzle 11 along the direction of the cleaning device towards the surface 101 to be cleaned, but those skilled in the art can also set the first nozzle to protrude from the second nozzle along the direction of the cleaning device towards the surface 101 to be cleaned according to actual needs.

Optionally, the first nozzle orifice 11 is disposed around the outer periphery of the second nozzle orifice 12.

Specifically, the first nozzle holes 11 for spraying the cleaning liquid are formed around the outer circumference of the second nozzle holes 12 for spraying the gas, so that the sprayed gas can be sufficiently mixed with the cleaning liquid to maximally form the supercritical fluid, thereby further improving the cleaning performance of the cleaning apparatus. In this embodiment, the first nozzle 11 may be symmetrically surrounded on the outer circumference of the second nozzle 12, or asymmetrically surrounded, and those skilled in the art can select the first nozzle according to actual needs. The shape of the second nozzle 12 may be, but is not limited to, circular, oval, rounded rectangular, or any polygon.

Fig. 2 is a bottom view of a nozzle in a cleaning device according to an embodiment of the present invention, and fig. 3 is a side view of the nozzle in the cleaning device according to the embodiment of the present invention. Alternatively, as shown in fig. 1 to 3, the cleaning device includes a nozzle including:

a nozzle body 13;

a first passage 30 inside the nozzle body 13 for communicating with the first spout 11;

a second channel 31 located inside the nozzle body 13 for communicating with the second nozzle 12, the second channel 31 being nested inside the first channel 30.

Specifically, as shown in fig. 1 to 3, the nozzle body 13 includes a first housing 20, and the first passage 30 and the second passage 31 are located in a cavity surrounded by the first housing 20. The first passage 30 is formed by a cavity surrounded by the second housing 21, and the second passage 31 is formed by a cavity surrounded by the third housing 22. In the present embodiment, the first channel 30 and the second channel 31 are cylindrical channels, and those skilled in the art can adjust the shapes of the first channel 30 and the second channel 31 according to actual needs. When the first nozzle orifice 11 can symmetrically surround the outer periphery of the second nozzle orifice 12, the axis of the first channel 30 coincides with the axis of the second channel 31, that is, the center of the first channel 30 is aligned with the center of the second channel 31. The first casing 20, the second casing 21 and the third casing 22 may be made of corrosion-resistant materials, so as to prolong the service life of the nozzle.

Optionally, the nozzle further comprises:

a first inlet 32 at an end of the nozzle body 13 facing away from the first spout 11 for delivering the cleaning liquid to the first channel 30, the first inlet 32 being disposed off-center of the nozzle body 13;

a second inlet 33 at an end of the nozzle body 13 facing away from the second nozzle orifice 12 for delivering the gas to the second passage 31, the second inlet 33 being aligned with a center of the nozzle body 13.

Specifically, the cleaning liquid is conveyed to the first channel 30 through the first pipe 14 communicated with the first inlet 32, and then is sprayed out through the first nozzle 11; the gas is transported to the second channel 32 through a second conduit 15 communicating with the second inlet 33 and ejected through the second nozzle 12. In this embodiment, the number of the first inlets 32 may be one or more. When the number of the first inlets 32 is plural and the number of the second inlets 33 is one, the plural first inlets 32 may be distributed around the outer circumference of the second inlets 33.

In the present embodiment, the description will be given taking an example in which the first nozzle hole 11 is provided around the outer periphery of the second nozzle hole 12. The skilled person can also arrange the first nozzle 11 and the second nozzle 12 in parallel according to actual needs, and the second nozzle 12 is located at one side of the first nozzle 11. However, when the second nozzle 12 is located on only one side of the first nozzle 11, the distance between the first nozzle 11 and the second nozzle 12 should be within a predetermined distance range to ensure that the cleaning solution sprayed from the first nozzle 11 can be mixed with the gas sprayed from the second nozzle 12 to form the supercritical fluid. The specific value of the preset distance may be set according to the flow rate of the cleaning liquid sprayed from the first nozzle 11, and the flow rate and the pressure of the gas sprayed from the second nozzle 12.

Optionally, the first nozzle 11 sprays the cleaning liquid in a direction perpendicular to the surface 101 to be cleaned;

the second nozzle 12 sprays the gas in a direction inclined with respect to the surface to be cleaned 101.

Specifically, when the first nozzle 11 is located right above the surface to be cleaned 101, the first nozzle 11 sprays the cleaning liquid toward the surface to be cleaned 101 in a vertically downward direction. The second nozzle 12 sprays the gas toward the surface to be cleaned in a direction inclined at a predetermined angle (acute angle) with respect to the axial direction of the surface to be cleaned 101. In this way, the supercritical fluid formed by mixing the cleaning liquid and the gas can obliquely flush the surface 101 to be cleaned, which helps to further improve the cleaning capability of removing impurities on the surface 101 to be cleaned and improve the cleaning effect. The specific value of the preset angle can be selected according to the relative sizes of the first nozzle 11 and the second nozzle 12, the flow rate and the pressure of the gas sprayed from the second nozzle 12, and other conditions.

Optionally, the cleaning device further comprises:

a first control valve 16 installed outside the nozzle for adjusting a flow rate of the cleaning liquid delivered to the first passage 30.

Optionally, the cleaning device further comprises:

a second control valve 17 installed outside the nozzle for adjusting a flow rate of the gas delivered to the second passage 31.

Optionally, the cleaning device further comprises:

a third control valve 18 installed outside the nozzle for adjusting the pressure of the gas delivered to the second passage 31.

Specifically, the flow rate of the cleaning liquid sprayed from the first nozzle 11 can be adjusted by the first control valve 16, so that the impurities with different sizes on the surface 101 to be cleaned can be flushed. The flow rate of the gas ejected from the second nozzle holes 12 can be adjusted by the second control valve 17, so that the supercritical fluid can be formed by mixing with the cleaning liquid at different flow rates. The pressure of the gas ejected from the second nozzle 12 can be adjusted by the third control valve 18, so that on one hand, damage to the cleaning device and the surface 101 to be cleaned caused by excessive pressure can be avoided; on the other hand, the formation of the supercritical fluid can be ensured according to the conditions such as the specific type and flow rate of the cleaning liquid.

Optionally, the cleaning solution is deionized water, and the gas is nitrogen or inert gas. The inert gas in this embodiment means a gas formed from an element of group VIII of the periodic table.

In the cleaning device provided by the embodiment of the invention, the first nozzle for spraying the cleaning liquid and the second nozzle for spraying the gas are respectively arranged, so that the cleaning liquid and the gas are sprayed to form the supercritical fluid, and the surface to be cleaned is cleaned by using the supercritical fluid; on the other hand, the supercritical fluid has high solubility to the particles, so that impurities remained on the surface to be cleaned can be reduced, and the cleaning capability of the cleaning device is improved. In addition, the gas released from the supercritical fluid can also effectively prevent the wafer from being corroded during the conveying process, thereby improving the quality of the wafer product.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A cleaning device, comprising:

2. The cleaning apparatus defined in claim 1, wherein the first nozzle orifice is disposed about an outer periphery of the second nozzle orifice.

3. The cleaning apparatus defined in claim 2, comprising a nozzle comprising: a nozzle body;

4. The cleaning device of claim 3, wherein the nozzle further comprises:

5. The cleaning apparatus defined in claim 1, wherein the first nozzle is disposed parallel to the second nozzle, and the second nozzle is located to one side of the first nozzle.

6. The cleaning device of claim 3, further comprising:

7. The cleaning device of claim 6, further comprising:

8. The cleaning device of claim 7, further comprising:

9. The cleaning apparatus as claimed in claim 1, wherein the first nozzle jets the cleaning liquid in a direction perpendicular to the surface to be cleaned;

10. The cleaning device of claim 1, wherein the cleaning solution is deionized water and the gas is nitrogen or an inert gas.