CN111266994A - cleaning device - Google Patents

Abstract

The present invention relates to a cleaning device. The cleaning device includes: a first nozzle for spraying cleaning liquid toward a surface to be cleaned; a second nozzle for spraying gas toward the surface to be cleaned, the cleaning liquid and the gas are mixed to form a supercritical fluid , to remove impurities remaining on the surface to be cleaned. On the one hand, the present invention improves the cleaning efficiency of the cleaning device; on the other hand, improves the cleaning capability of the cleaning device. In addition, the gas released from the supercritical fluid can also effectively prevent the wafers from being corroded during transportation, thereby improving the quality of wafer products.

Description

cleaning device

technical field

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

Background technique

With the development of planar flash memory, the production process of semiconductors has made great progress. However, in recent years, the development of planar flash memory has encountered various challenges: physical limits, existing development technology limits, and storage electron density limits. In this context, in order to solve the difficulties encountered by planar flash memory and pursue lower production costs per unit of memory cells, various three-dimensional (3D) flash memory structures have emerged, such as 3D NOR (3D or non) flash memory and 3D NAND (3D and not) flash memory.

Among them, 3D NAND memory is based on its small size and large capacity, and the high integration of storage cells using three-dimensional mode layer-by-layer stacking is the design concept to produce memory with high storage density per unit area and high-efficiency storage unit performance. It has become an emerging memory The mainstream process of design and production.

In the manufacturing process of semiconductor devices such as 3D NAND memory, chemical mechanical polishing (Chemical Mechanical Polish, CMP) is a crucial step. However, whether the surface of the polishing pad in the chemical mechanical polishing device is clean or not is an important indicator for the smooth progress of the chemical mechanical polishing process and for evaluating the quality of the chemical mechanical polishing. However, the existing method cannot effectively remove impurities on the surface of the polishing pad, and the cleaning efficiency is low, which leads to the risk of the wafer being scratched during the chemical mechanical polishing process, and reduces the productivity of the chemical mechanical polishing device.

Therefore, how to improve the cleaning quality of the polishing pad in the chemical mechanical polishing device and improve the cleaning efficiency of the polishing pad is a technical problem that needs to be solved urgently at present.

SUMMARY OF THE INVENTION

The present invention provides a cleaning device for solving the problem of poor cleaning efficiency of the existing cleaning methods, so as to improve the cleaning effect.

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

a first nozzle for spraying cleaning fluid toward a surface to be cleaned;

The second nozzle is used for spraying gas toward the surface to be cleaned, and the cleaning liquid is mixed with the gas to form a supercritical fluid, so as to remove impurities remaining on the surface to be cleaned.

Optionally, the first spout is arranged around the outer circumference of the second spout.

Optionally, include a nozzle comprising:

Nozzle body;

a first channel, located inside the nozzle body, for communicating with the first nozzle;

A second channel is located inside the nozzle body for communicating with the second nozzle, and the second channel is nested in the first channel.

Optionally, the nozzle further includes:

a first inlet, located at the end of the nozzle body away from the first spray port, used for transmitting the cleaning liquid to the first channel, the first inlet is arranged offset from the center of the nozzle body;

A second inlet is located at the end of the nozzle body away from the second spout, and is used to transmit the gas to the second passage, the second inlet is aligned with the center of the nozzle body.

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

Optionally, also include:

A first control valve, installed outside the nozzle, is used to adjust the flow rate of the cleaning liquid transmitted to the first channel.

Optionally, also include:

A second control valve, installed outside the nozzle, is used to adjust the flow rate of the gas delivered to the second passage.

Optionally, also include:

A third control valve, installed outside the nozzle, adjusts the pressure of the gas delivered to the second passage.

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

The second nozzle sprays 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 an inert gas.

In the cleaning device provided by the present invention, a first nozzle for spraying cleaning liquid and a second nozzle for spraying gas are respectively arranged, so that the cleaning liquid and the gas are sprayed to form a supercritical fluid, and the supercritical fluid is formed by using the supercritical fluid. The critical fluid cleans the surface to be cleaned. On the one hand, due to the dispersion of the gas, the area of the formed supercritical fluid for single cleaning increases, thereby improving the cleaning efficiency of the cleaning device; on the other hand, the supercritical fluid The solubility of particulate matter is relatively large, so that impurities remaining on the surface to be cleaned can be reduced, and the cleaning capability of the cleaning device can be improved. In addition, the gas released from the supercritical fluid can also effectively prevent the wafers from being corroded during transportation, thereby improving the quality of wafer products.

Description of drawings

1 is a schematic diagram of the overall structure of a cleaning device in a specific embodiment of the present invention;

2 is a bottom view of the nozzle in the cleaning device in the specific embodiment of the present invention;

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

Detailed ways

The specific embodiments of the cleaning device provided by the present invention will be described in detail below with reference to the accompanying drawings.

In the current chemical mechanical polishing apparatus, the cleaning liquid nozzle for cleaning the polishing pad is usually installed directly below the polishing arm. When using this structure to clean the surface of the polishing pad before grinding the wafer, the cleaning solution can only be sprayed on the surface of the polishing pad directly below the cleaning solution nozzle. The cleaning efficiency of the polishing pad is reduced; on the other hand, although the polishing arm will move with the cleaning liquid nozzle in a preset step size, because the cleaning liquid nozzle has a limited area for cleaning with a single injection of the cleaning liquid, it will also be difficult to clean. Reduced cleaning ability of the polishing pad. The reduction in the cleaning efficiency of the polishing pad will prolong the downtime of the chemical mechanical polishing device, thereby resulting in a reduction in the production capacity of the chemical mechanical polishing device. The reduction of the cleaning ability of the polishing pad will result in the residual particles on the surface of the polishing pad. During the subsequent chemical mechanical polishing of the wafer, scratches are easily formed on the surface of the wafer, which affects the quality of the wafer product. , and even lead to the scrapping of the wafer in severe cases.

In order to improve the cleaning performance of semiconductor equipment such as polishing pads, this embodiment provides a cleaning device, and FIG. 1 is a schematic diagram of the overall structure of the cleaning device in the embodiment of the present invention. As shown in Figure 1, the cleaning device provided by this specific embodiment includes:

The first nozzle 11 is used to spray cleaning liquid toward a surface 101 to be cleaned;

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

Supercritical state refers to the state in which the pressure and temperature of a substance exceed its critical pressure and critical temperature at the same time; supercritical fluid refers to a fluid whose temperature and pressure are both above the critical point. The supercritical fluid in this specific embodiment refers to a mixed fluid including the cleaning liquid and the gas in a supercritical state.

Specifically, the surface to be cleaned 101 may be any surface used for processing wafers on semiconductor equipment. In this specific embodiment, the surface to be cleaned 101 is taken as an example of the surface of the polishing pad 10 used for carrying wafers for description. The first nozzle 11 and the second nozzle 12 are disposed above the surface to be cleaned 101 along a direction perpendicular to the surface to be cleaned 101 (ie, the Z-axis direction in FIG. 1 ). While the first nozzle 11 sprays the cleaning liquid to the surface to be cleaned 101 , the second nozzle 12 sprays the gas to the surface to be cleaned 101 , and the gas is mixed with the cleaning liquid After the supercritical fluid is formed, it falls to the surface to be cleaned 101 . The area of the surface to be cleaned 101 cleaned by the supercritical fluid is greatly increased, thereby improving the cleaning efficiency of the surface to be cleaned, reducing the waiting time for semiconductor equipment such as chemical mechanical polishing devices to stop, and improving the chemical mechanical polishing. The production capacity of semiconductor equipment such as devices. 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 also reduced, the cleaning ability of the cleaning device is improved, and the surface defects of the wafer are improved. . Not only that, the solubility of the supercritical fluid for particulate impurities such as silica 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, in 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 to prevent the wafer from being corroded during the transfer process.

In this specific embodiment, the specific type of the cleaning liquid can be selected according to the type of the surface 101 to be cleaned, for example, it can be, 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 can also be selected by those skilled in the art according to actual needs, for example, according to the specific type of the cleaning liquid. This is not limited, as long as the sprayed gas can form a supercritical fluid with the sprayed deionized water. This specific embodiment is described by taking the second nozzle 12 protruding from the first nozzle 11 along the direction of the cleaning device to the surface to be cleaned 101 as an example for description, however, those skilled in the art can also make the The first spout is arranged to protrude from the second spout in a direction in which the cleaning device is directed towards the surface to be cleaned 101 .

Optionally, the first spout 11 is arranged around the outer circumference of the second spout 12 .

Specifically, the first jet port 11 for jetting the cleaning liquid is arranged around the outer periphery of the second jet port 12 for jetting the gas, so that the jetted gas can be sufficiently compatible with the cleaning liquid mixed to maximize the formation of the supercritical fluid, thereby further improving the cleaning efficiency of the cleaning device. In this specific embodiment, the first nozzle 11 can be symmetrically surrounded by the outer circumference of the second nozzle 12, or can be asymmetrically surrounded, and those skilled in the art can choose according to actual needs. The shape of the second spout 12 may be, but not limited to, a circle, an ellipse, a rectangle with rounded corners, or any polygon.

FIG. 2 is a bottom view of the nozzle in the cleaning device in the specific embodiment of the present invention, and FIG. 3 is a side view of the nozzle in the cleaning device in the specific embodiment of the present invention. Optionally, as shown in FIGS. 1-3 , the cleaning device includes a nozzle, and the nozzle includes:

Nozzle body 13;

a first channel 30, located inside the nozzle body 13, for communicating with the first nozzle 11;

The second channel 31 is located inside the nozzle body 13 and is used for communicating with the second nozzle 12 , and the second channel 31 is nested in the first channel 30 .

Specifically, as shown in FIGS. 1 to 3 , the nozzle body 13 includes a first casing 20 , and both the first passage 30 and the second passage 31 are located around the first casing 20 . into the cavity. The first channel 30 is constituted by a cavity surrounded by the second casing 21 , and the second channel 31 is constituted by a cavity surrounded by the third casing 22 . In this specific embodiment, the first channel 30 and the second channel 31 are both cylindrical channels for illustration, and those skilled in the art can also adjust the first channel 30 and all the channels according to actual needs. The shape of the second channel 31 is described. When the first spout 11 can surround the outer circumference of the second spout 12 symmetrically, 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 the same as the axis of the second channel 31 . The centers of the second channels 31 are aligned. Wherein, the first casing 20, the second casing 21 and the third casing 22 may be made of corrosion-resistant materials, so as to improve the service life of the nozzle.

Optionally, the nozzle further includes:

The first inlet 32 is located at the end of the nozzle body 13 away from the first nozzle 11 , and is used to transmit the cleaning liquid to the first channel 30 , and the first inlet 32 is offset from the nozzle body 13 . center settings;

The second inlet 33 is located at the end of the nozzle body 13 away from the second nozzle 12 , and is used to transmit the gas to the second passage 31 , the second inlet 33 and the center of the nozzle body 13 Align the settings.

Specifically, the cleaning liquid is transmitted to the first channel 30 through the first pipe 14 communicating with the first inlet 32, and then ejected through the first nozzle 11; The second pipe 15 connected with the two inlets 33 is transmitted to the second channel 32 , and then sprayed out through the second nozzle 12 . In this specific implementation manner, the number of the first inlets 32 may be one or multiple. When the number of the first inlets 32 is multiple and the number of the second inlets 33 is one, a plurality of the first inlets 32 may be distributed around the outer circumference of the second inlet 33 .

In this specific embodiment, the first nozzle 11 is arranged around the outer circumference of the second nozzle 12 as an example for description. Those skilled in the art 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 on one side of the first nozzle 11 . However, when the second nozzle 12 is located at and only on 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, In order to ensure that the cleaning liquid 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 can be set according to the flow rate of the cleaning liquid sprayed by the first nozzle 11 and the flow rate and pressure of the gas sprayed by 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 directly 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 gas toward the surface to be cleaned in a direction inclined at a predetermined angle (acute angle) relative to the axis direction of the surface to be cleaned 101 . In this way, the supercritical fluid formed by mixing the cleaning liquid and the gas can wash the surface 101 to be cleaned obliquely, which is helpful to further improve the ability to remove impurities on the surface 101 to be cleaned, and improve the cleaning effect. Wherein, the specific value of the preset angle can be selected according to the relative size of the first nozzle 11 and the second nozzle 12, as well as the flow rate and pressure of the gas ejected from the second nozzle 12 and other conditions. .

Optionally, the cleaning device further includes:

The first control valve 16 , installed outside the nozzle, is used to adjust the flow rate of the cleaning liquid transmitted to the first channel 30 .

Optionally, the cleaning device further includes:

A second control valve 17 , installed outside the nozzle, is used to adjust the flow rate of the gas transmitted to the second passage 31 .

Optionally, the cleaning device further includes:

A third control valve 18, installed outside the nozzle, is used to adjust 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 through the first control valve 16 , so that impurities of different sizes on the surface 101 to be cleaned can be washed. The flow rate of the gas ejected from the second nozzle 12 can be adjusted through the second control valve 17, so that the supercritical fluid can be formed by mixing with the cleaning liquid of different flow rates. The pressure of the gas ejected from the second nozzle 12 can be adjusted through the third control valve 18. On the one hand, damage to the cleaning device and the surface to be cleaned 101 caused by excessive pressure can be avoided; On the one hand, the formation of the supercritical fluid can also be ensured according to the specific type, flow rate and other conditions of the cleaning liquid.

Optionally, the cleaning solution is deionized water, and the gas is nitrogen or an inert gas. The inert gas described in this specific embodiment refers to a gas formed from elements of Group VIII in the periodic table of elements.

In the cleaning device provided by this specific embodiment, by respectively setting a first nozzle for spraying cleaning liquid and a second nozzle for spraying gas, the cleaning liquid and the gas are sprayed to form a supercritical fluid, and the cleaning liquid and the gas are sprayed to form a supercritical fluid. The surface to be cleaned is cleaned by the supercritical fluid. On the one hand, due to the dispersion of the gas, the area of the formed supercritical fluid for single cleaning is increased, thereby improving the cleaning efficiency of the cleaning device; The solubility of the fluid to the particles is relatively large, so that impurities remaining on the surface to be cleaned can be reduced, and the cleaning ability of the cleaning device can be improved. In addition, the gas released from the supercritical fluid can also effectively prevent the wafers from being corroded during transportation, thereby improving the quality of wafer products.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can also be made, and these improvements and modifications should also be regarded as It is the protection scope of the present invention.

Claims (10)

1. A cleaning device, characterized in that, comprising: a first nozzle for spraying cleaning fluid toward a surface to be cleaned; The second nozzle is used for spraying gas toward the surface to be cleaned, and the cleaning liquid is mixed with the gas to form a supercritical fluid, so as to remove impurities remaining on the surface to be cleaned. 2 . The cleaning device according to claim 1 , wherein the first nozzle is arranged around the outer circumference of the second nozzle. 3 . 3 . The cleaning device according to claim 2 , comprising a nozzle, the nozzle comprising: a nozzle body; 3 . a first channel, located inside the nozzle body, for communicating with the first nozzle; A second channel is located inside the nozzle body for communicating with the second nozzle, and the second channel is nested in the first channel. 4. The cleaning device of claim 3, wherein the nozzle further comprises: a first inlet, located at the end of the nozzle body away from the first spray port, used for transmitting the cleaning liquid to the first channel, the first inlet is arranged offset from the center of the nozzle body; A second inlet is located at the end of the nozzle body away from the second spout, and is used to transmit the gas to the second passage, the second inlet is aligned with the center of the nozzle body. 5 . The cleaning device according to claim 1 , wherein the first nozzle and the second nozzle are arranged in parallel, and the second nozzle is located on one side of the first nozzle. 6 . 6. The cleaning device of claim 3, further comprising: A first control valve, installed outside the nozzle, is used to adjust the flow rate of the cleaning liquid transmitted to the first channel. 7. The cleaning device of claim 6, further comprising: A second control valve, installed outside the nozzle, is used to adjust the flow rate of the gas delivered to the second passage. 8. The cleaning device of claim 7, further comprising: A third control valve, installed outside the nozzle, adjusts the pressure of the gas delivered to the second passage. 9. The cleaning device according to claim 1, wherein the first nozzle sprays the cleaning liquid in a direction perpendicular to the surface to be cleaned; The second nozzle sprays the gas in a direction inclined with respect to the surface to be cleaned. 10 . The cleaning device according to claim 1 , wherein the cleaning liquid is deionized water, and the gas is nitrogen or an inert gas. 11 .

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