CN117976531A

CN117976531A - Polishing method and method for manufacturing semiconductor device

Info

Publication number: CN117976531A
Application number: CN202311848069.5A
Authority: CN
Inventors: 季明华
Original assignee: Shanghai Chuanxin Semiconductor Co ltd
Current assignee: Shanghai Chuanxin Semiconductor Co ltd
Priority date: 2023-12-28
Filing date: 2023-12-28
Publication date: 2024-05-03

Abstract

The invention provides a polishing method and a preparation method of a semiconductor device. Wherein the polishing method is to spray a plurality of beams of the fluid along the surface of the substrate to form a nearly horizontal acting force on the surface of the substrate. And the acting force formed by the fluid molecules can effectively wash away pollutants on the surface of the substrate and cut the protruding structure on the surface of the substrate, so that the high-speed fine polishing of the surface of the substrate is realized. Meanwhile, in the polishing process, the substrate rotates according to a preset track, so that the fluid can flow on the surface of the substrate, drive molecular groups formed by cutting to flow, and flow through pits on the surface of the substrate, and fill and repair the pits. Therefore, the polishing method provided by the invention can synchronously realize high-speed fine polishing and repairing of the surface of the substrate, and has high polishing efficiency and good polishing quality.

Description

Polishing method and method for manufacturing semiconductor device

Technical Field

The present invention relates to the field of integrated circuit manufacturing technology, and in particular, to a polishing method and a method for manufacturing a semiconductor device.

Background

With the development of integrated circuit (INTEGRATED CIRCUIT) fabrication technology, the requirements for the polishing quality of semiconductor structures and their associated components are increasing. The existing Polishing process generally adopts a chemical mechanical Polishing process (CHEMICAL MECHANICAL Polishing process, CMP) to carry out rough Polishing, and adopts a Polishing process such as laser, plasma beam or magneto-rheological to carry out fine Polishing. However, the consumption of consumables in the chemical mechanical polishing process is large, abrasive particles in the polishing solution easily pollute and damage the polishing surface, the polishing quality is seriously affected, and high-precision polishing cannot be realized. The laser polishing process ablates the surface of the material to improve the roughness, and the precision polishing requirement is difficult to meet. And, although ion beam or magneto-rheological polishing process can realize nano-scale precision polishing, the removal speed is very limited, the cost of the apparatus and equipment is high, and batch polishing is difficult to implement.

Therefore, a new polishing process is needed to achieve rapid and high-precision polishing.

Disclosure of Invention

The present invention is directed to a polishing method and a method for manufacturing a semiconductor device, which solve at least one of the problems of how to improve polishing efficiency, how to improve polishing quality, and how to reduce polishing cost.

In order to solve the above technical problems, the present invention provides a polishing method, including:

Providing a substrate;

and spraying a plurality of beams of fluid along the surface of the substrate, and rotating the substrate in a preset track to enable the fluid to flow on the surface of the substrate and polish the surface of the substrate.

Optionally, in the polishing method, the plurality of beams of fluid flow attached to the substrate surface and/or flow parallel to the substrate surface.

Optionally, in the polishing method, the plurality of beams of fluid are ejected in the same direction along the surface of the substrate, or portions of the beams of fluid are ejected in different directions along the surface of the substrate.

Optionally, in the polishing method, the substrate is heated before or during polishing the surface of the substrate with the plurality of beams of fluid.

Optionally, in the polishing method, the temperature of the substrate is less than or equal to 100 ℃.

Optionally, in the polishing method, during polishing the surface of the substrate with the plurality of beams of fluid, a baffle plate is used to adjust the pressure of the fluid relative to the surface of the substrate; wherein, the baffle is located above the substrate, and the interval range with the substrate surface is: 1 mm-10 mm.

Optionally, in the polishing method, the substrate surface has at least a protruding structure and a pit, and in the process of polishing the substrate surface with the plurality of beams of fluid, the fluid removes the protruding structure and causes a cluster of the protruding structure to flow to the pit along with the fluid so as to fill the pit.

Optionally, in the polishing method, the substrate rotates at a constant speed or a variable speed according to the preset track, and the rotation speed of the substrate is less than or equal to 1000rpm.

Optionally, in the polishing method, the fluid is a chemically inactive and abrasive-free liquid and/or gas, including: pure water, isopropanol, water vapor, organic vapor or inert gas.

Based on the same inventive concept, the present invention provides a method for manufacturing a semiconductor device, including the polishing method.

In summary, the present invention provides a polishing method and a method for manufacturing a semiconductor device. Wherein the polishing method is to spray a plurality of beams of the fluid along the surface of the substrate to form a nearly horizontal acting force on the surface of the substrate. And the acting force formed by the fluid molecules can effectively wash away pollutants on the surface of the substrate and cut the protruding structure on the surface of the substrate, so that the high-speed fine polishing of the surface of the substrate is realized. Meanwhile, in the polishing process, the substrate rotates according to a preset track, so that the fluid can flow on the surface of the substrate, drive molecular groups formed by cutting to flow, and flow through pits on the surface of the substrate, and fill and repair the pits. Therefore, the polishing method provided by the invention can synchronously realize high-speed fine polishing and repairing of the surface of the substrate, and has high polishing efficiency and good polishing quality.

Drawings

Those of ordinary skill in the art will appreciate that the figures are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

Fig. 1 is a flow chart of a polishing method in an embodiment of the present invention.

Fig. 2 is a schematic diagram of a substrate surface defect in an embodiment of the invention.

FIG. 3 is a schematic illustration of fluid ejection in a direction parallel to a substrate surface in an embodiment of the invention.

FIG. 4 is a schematic view of a fluid being sprayed onto a surface of a substrate at a large oblique angle in an embodiment of the present invention.

FIG. 5 is a schematic top view of a fluid jet with substrate rotation in a co-current direction in an embodiment of the invention.

FIG. 6 is a schematic top view of a fluid multi-directional spray and substrate rotation in an embodiment of the invention.

Fig. 7 is a schematic diagram of a fluid carrying molecular cluster filling pit in an embodiment of the invention.

Fig. 8 is a schematic structural view of a fluid-polished substrate in accordance with an embodiment of the present invention.

FIG. 9 is a schematic view of a baffle plate disposed in parallel over a substrate in an embodiment of the present invention.

FIG. 10 is a schematic view of a baffle plate angularly disposed over a substrate in an embodiment of the present invention.

And, in the drawings:

100-a substrate; 200-fluid; 300-baffle;

c-contaminants; a P-projection structure; a p-molecular group; t-pits; d-spacing of the baffle plate from the surface of the substrate; v-direction of rotation; the angle of the θ -fluid ejection direction to the substrate surface.

Detailed Description

The invention will be described in further detail with reference to the drawings and the specific embodiments thereof in order to make the objects, advantages and features of the invention more apparent. It should be noted that the drawings are in a very simplified form and are not drawn to scale, merely for convenience and clarity in aiding in the description of embodiments of the invention. Furthermore, the structures shown in the drawings are often part of actual structures. In particular, the drawings are shown with different emphasis instead being placed upon illustrating the various embodiments.

As used in this disclosure, the singular forms "a," "an," and "the" include plural referents, the term "or" are generally used in the sense of comprising "and/or" and the term "several" are generally used in the sense of comprising "at least one," the term "at least two" are generally used in the sense of comprising "two or more," and the term "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance or number of features indicated. Thus, a feature defining "a first", "a second", "a third" may include either explicitly or implicitly one or at least two of such features, and the terms "mounted", "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. Furthermore, as used in this disclosure, an element disposed on another element generally only refers to a connection, coupling, cooperation or transmission between two elements, and the connection, coupling, cooperation or transmission between two elements may be direct or indirect through intermediate elements, and should not be construed as indicating or implying any spatial positional relationship between the two elements, i.e., an element may be in any orientation, such as inside, outside, above, below, or on one side, of the other element unless the context clearly indicates otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1, the present embodiment provides a polishing method, including:

Step one S10: a substrate is provided.

Step two S20: and spraying a plurality of beams of fluid along the surface of the substrate, and rotating the substrate in a preset track to enable the fluid to flow on the surface of the substrate and polish the surface of the substrate.

It will be appreciated that the polishing method provided by the present embodiment utilizes a plurality of beams of the fluid to be sprayed along the substrate surface to create a nearly horizontal force on the substrate surface. And the acting force formed by the fluid molecules can effectively wash away pollutants on the surface of the substrate and cut the protruding structure on the surface of the substrate, so that the high-speed fine polishing of the surface of the substrate is realized. Meanwhile, in the polishing process, the substrate rotates according to a preset track, so that the fluid can flow on the surface of the substrate, drive molecular groups formed by cutting to flow, and flow through pits on the surface of the substrate, and fill and repair the pits. Therefore, the polishing method provided by the embodiment can synchronously realize high-speed fine polishing and repairing of the surface of the substrate, and has high polishing efficiency and good polishing quality.

The polishing method provided in this embodiment is specifically described below with reference to fig. 1 to 10.

Step one S10: referring to fig. 2, a substrate 100 is provided.

The substrate 100 in this embodiment is a semiconductor structure, a mask, or other plate to be polished. The specific material of the substrate 100 is not limited to this embodiment, and may be a quartz glass substrate, a soda lime substrate, a borosilicate substrate, an aluminum silicate substrate, a silicon carbide substrate, or the like used as a mask blank; or any substrate known to those skilled in the art for carrying the components of a semiconductor integrated circuit, such as a die, a wafer after being subjected to an epitaxial growth process, a circuit layer or other semiconductor film on which devices have been formed. Such as a gallium nitride film, a silicon-on-insulator (SOI) substrate, a bulk silicon (bulk silicon) substrate, a germanium substrate, a silicon germanium substrate, an indium phosphide (InP) substrate, a gallium arsenide (GaAs) substrate, or a germanium-on-insulator substrate, etc.

The substrate 100 to be polished generally has defects such as contaminants C, protruding structures P, and pits T on its surface. The contaminant C may be separated from the surface of the substrate 100, and may be removed by a cleaning process before polishing, or may be removed directly by a subsequent polishing process. The protruding structures P are structurally connected to the substrate 100, which is difficult to be removed by cleaning or purging, and the conventional CMP rough polishing process is also difficult to remove the minute protruding structures P. The pit T may be a deep groove on the surface of the substrate 100, or may be a slight scratch or crack. In this regard, the existing polishing process can only improve the flatness of the substrate 100 by thinning and flattening; or, the pit T is repaired by a carbon spin coating process alone. Both of these approaches, however, add cost and impact manufacturing efficiency. The polishing method provided by the embodiment not only can remove the pollutant C and the protruding structure P, but also can synchronously repair the pit T, thereby effectively improving the polishing quality and the polishing efficiency, and having low polishing cost. (see the following description of FIGS. 3-10 for a specific polishing process)

Step two S20: referring to fig. 3 to 10, a plurality of beams of fluid 200 are sprayed along the surface of the substrate 100, and the substrate 100 is rotated in a predetermined trajectory so that the fluid 200 flows on the surface of the substrate 100 and polishes the surface of the substrate 100.

It will be appreciated that this embodiment optimizes the flatness of the surface of the substrate 100 by means of jet polishing. In particular, the fluid 200 employed in this embodiment is a chemically non-reactive and abrasive-free liquid and/or gas. Preferably, the fluid 200 includes, but is not limited to, one or more of pure water, isopropyl alcohol, water vapor, organic vapor, and inert gas. For example, a mixed fluid 200 composed of pure water and water vapor is sprayed along the surface of the substrate 100 to polish the surface of the substrate 100. It should be noted that, the fluid 200 provided in this embodiment does not include a chemically active additive and abrasive particles. The arrangement can accelerate the movement of the fluid 200 to realize rapid and fine polishing, avoid the new defects of the surface of the substrate 100 caused by chemical active substances and abrasive particles in the polishing process, and ensure better polishing quality.

Preferably, the spraying direction of the plurality of beams 200 is parallel to the surface of the substrate 100 as much as possible, and/or is sprayed at a large inclination angle θ with respect to the surface of the substrate 100, so that the plurality of beams 200 can flow attached to the surface of the substrate 100, and/or flow parallel to the surface of the substrate 100. As shown in fig. 3, the fluid 200 is sprayed in a direction parallel to the substrate 100, so that numerous small molecules of the fluid 200 continuously strike the contaminants C and the protruding structures P on the surface of the substrate 100 during the rapid flow process to wash the contaminants C away from the surface of the substrate 100, and apply a force in a parallel direction to the protruding structures P to cut the protruding structures P at one time or step by step, thereby optimizing the flatness of the surface of the substrate 100. And, as shown in fig. 4, when the fluid 200 is sprayed to the surface of the substrate 100 at a large inclination angle θ, the contaminants C are also washed away and the protrusion structures P are removed from the surface of the substrate 100 with a shearing force in a nearly parallel direction. It should be noted that the fluid 200 is composed of innumerable molecules and has high fluidity, so that the contaminants C and the protruding structures P can be removed even at a molecular level or even at an atomic level during polishing the surface of the substrate 100, thereby having a good polishing effect.

Further, the flow rate and velocity of the fluid 200 are different, and the force applied to the surface of the substrate 100 is different. The flow rate and the flow velocity of the fluid 200 are not particularly limited in this embodiment, and may be adjusted according to the material of the substrate 100 and the required flatness. And, the specific jetting direction of the plurality of beams of fluid 200 with respect to the substrate 100 is not limited in this embodiment. Illustratively, as shown in fig. 5, the plurality of beams of fluid 200 are ejected in the same direction along the surface of the substrate 100. That is, all of the fluid 200 impinges on the surface of the substrate 100 from the same location, and the initial force provided by the fluid 200 to the contaminant C and the projection arrangement P on the surface of the substrate 100 is in the same direction. Or as shown in fig. 6, portions of the beam of fluid 200 are ejected in different directions along the surface of the substrate 100. That is, if a portion of the fluid 200 impinges on the surface of the substrate 100 from a different location, the initial force provided by the fluid 200 against the contaminant C and the protruding structure P on the surface of the substrate 100 is different. In other embodiments, the plurality of beams 200 are in the form of dynamic jets. For example, during polishing, the nozzle for providing the fluid 200 rotates along the circumferential direction of the substrate 100, so that the fluid 200 is incident on the surface of the substrate 100 at different positions, and the initial force provided by the fluid 200 to the surface of the substrate 100 is different in direction, so that the contaminant C and the protrusion structure P are subjected to multi-directional force, and polishing efficiency is improved.

In order to improve the utilization rate and polishing efficiency of the fluid 200, the substrate 100 rotates in a predetermined trajectory during the polishing process, and the fluid 200 rotates on the surface of the substrate 100 along with the rotation of the substrate 100, so that the contaminants C and the protruding structures P on the surface of the substrate 100 can be repeatedly impacted. For example, as shown in fig. 3 and 5, the rotation direction V of the substrate 100 is clockwise, and the fluid 200 flowing to the surface of the substrate 100 is rotated clockwise by the rotation of the substrate 100, thereby forming a circulation on the surface of the substrate 100. Based on this, under the cyclic rotation of the fluid 200, the contaminant C and the protruding structure P on the surface of the substrate 100 are continuously subjected to a circumferential force, so as to quickly flush away the contaminant C and cut the protruding structure P, and at the same time, under the rotation of the substrate 100, the clusters of the contaminant C and the cut protruding structure P can be quickly thrown away from the surface of the substrate 100, so as to avoid secondary damage to the substrate 100 caused by the substance structure separated from the substrate 100. It should be noted that, the specific rotation track of the substrate 100 is not limited in this embodiment, and the substrate may be rotated in a clockwise direction or a counterclockwise direction all the time, or may be rotated in a clockwise direction for a period of time and then rotated in a counterclockwise direction for a period of time as shown in fig. 6. And, the specific rotation speed of the substrate 100 is not limited in this embodiment, and may be constant rotation or variable rotation, and the rotation speed of the substrate 100 may be dynamically adjusted during the polishing process. Preferably, the rotational speed of the substrate 100 is less than or equal to 1000rpm.

It should be noted that, during polishing, the fluid 200 not only can rapidly remove the contaminants C and the protruding structures P on the surface of the substrate 100, but also can simultaneously repair the pits T on the surface of the substrate 100. Referring to fig. 7 and 8, the convex structures P on the surface of the substrate 100 are sheared into a plurality of clusters P under the constant impact of the fluid 200. A plurality of the molecular groups p may enter the pit T with the fluid 200 attached to the surface of the substrate 100 and be deposited in the pit T. In addition, when the substrate 100 rotates, a circulation is formed on the surface of the substrate 100, and the circulation drives countless molecular groups p to repeatedly move on the surface of the substrate 100, the molecular groups p with larger mass gradually accumulate in the pit T and fill the pit T. Because the circulation flow has a high speed and is changeable in direction, not only can a shearing force parallel to the surface of the substrate 100 be formed to remove the protruding structure P, but also a strong fluid 200 pressure can be formed on the surface of the pit T, so that the molecular group P accumulated in the pit T is pressed in the pit T, and repair of the pit T is realized. Preferably, the contaminants C on the surface of the substrate 100 are removed by a cleaning process before polishing the substrate 100, so as to avoid secondary damage to the substrate 100 due to the contaminants C entering the pits T with a circulating current during the polishing process. Further, it will be appreciated that the forces exerted by the fluid 200 on the respective projection structures P will be different in view of the differences in flow rates and flow rates of the fluid 200. Thus, the size of the formed clusters p can be micro-scale, nano-scale or even atomic-scale, and the repairing requirements of the pits T with different sizes can be met. Based on this, the polishing method provided in this embodiment not only can finely polish the surface of the substrate 100, but also can repair the pit T on the surface of the substrate 100 synchronously, without performing large-size thinning or performing repair processes such as carbon spin coating alone, so that the polishing quality and polishing effect are effectively improved, and the preparation cost is reduced.

Further, before or during polishing the surface of the substrate 100 with the plurality of beams of fluid 200, the substrate 100 may be heated by a heater to accelerate the movement of molecules in the substrate 100, which is not only beneficial to promoting the cutting and polishing of the protruding structures P by the fluid 200, but also beneficial to promoting the interaction between the clusters P in the pits T and the material molecules in the substrate 100, so as to improve the polishing efficiency and the polishing quality. Here, the heating time and the heating temperature of the substrate 100 are not particularly limited in this embodiment. In order to avoid the influence of the excessive temperature on the substrate 100, it is preferable that the temperature range of the substrate 100 is: room temperature to 100 ℃. Furthermore, in the polishing process, the fluid 200 may be heated, so that the fluidity of the fluid 200 is promoted, the polishing is accelerated, the surface tension of molecules of the fluid 200 is reduced, the molecules are easily attached to the surface of the substrate 100, and the tiny protruding structures P are cut, so that the polishing precision is improved.

Referring to fig. 9 and 10, in view of the different materials of the substrate 100 and the different defect degrees of the surface of the substrate 100, it is preferable to adjust the pressure of the fluid 200 relative to the surface of the substrate 100 by using the baffle 300 during the process of polishing the surface of the substrate 100 by using the plurality of beams of the fluid 200, so as to adjust the force of the fluid 200 on the surface of the substrate 100. Specifically, the baffle 300 is located above the substrate 100 and covers at least a portion of the surface of the substrate 100. Based on this, the space on the surface of the substrate 100 is compressed, so that when the fluid 200 flows along the surface of the substrate 100, a large amount of the fluid 200 is compressed in a limited flow space, resulting in a reduced gap of the movement of the fluid 200 molecules, aggravated the movement between the fluid 200 molecules, improved the flow velocity of the fluid 200, formed a nozzle effect, and further improved the polishing efficiency. The distance D between the baffle 300 and the surface of the substrate 100 is not limited in this embodiment, and optionally, the distance D may be within the range of: 1 mm-10 mm.

Preferably, as shown in fig. 9, the baffle 300 is parallel to the surface of the substrate 100, or, as shown in fig. 10, the baffle 300 is disposed at an angle with respect to the substrate 100, that is, the baffle 300 is disposed obliquely above the substrate 100, so that the distance between the baffle 300 and the surface of the substrate 100 changes in a gradient, and correspondingly, the space above the substrate 100 also changes in a gradient, so that the pressure and the flow rate of the fluid 200 gradually decrease with the increase of the space. Preferably, during polishing, the inflow end of the fluid 200 is pressurized more than the outflow end of the fluid 200, so that the fluid 200 can quickly carry the removal particles out of the reaction chamber where the substrate 100 is located, ensuring stable pressure in the reaction chamber, and ensuring removal particles to be removed from the reaction chamber in time.

It should be noted that, in this embodiment, only polishing a single surface of the substrate 100 is taken as an example, in other embodiments, a plurality of beams of the fluid 200 may be used to polish two opposite surfaces of the substrate 100 at the same time, and the specific polishing process refers to the above-mentioned polishing process for a single surface of the substrate 100, which is not described herein.

Based on the same inventive concept, the embodiment also provides a method for manufacturing the semiconductor device. The preparation method of the semiconductor device comprises the polishing method. That is, the polishing method may be employed to polish the semiconductor device in whole or in part during the manufacture of the semiconductor device. Further, the polishing method provided in this embodiment may also be applicable to the manufacturing field of other devices, and this embodiment is not particularly limited.

In summary, the present embodiment provides a polishing method and a method for manufacturing a semiconductor device. The polishing method is to use a plurality of beams of the fluid 200 to spray along the surface of the substrate 100 to form a force in a nearly horizontal direction to the surface of the substrate 100, so as to wash the pollutant C on the surface of the substrate 100 and cut the protruding structures P on the surface of the substrate 100. Meanwhile, based on the rotation of the substrate 100, the fluid 200 can form a circulation on the surface of the substrate 100 to drive the molecular groups p formed by cutting to flow and flow through the pits T on the surface of the substrate 100, so as to realize filling and repairing of the pits T. Therefore, the polishing method provided by the embodiment can synchronously realize high-speed fine polishing and repair of the surface of the substrate 100, and has high polishing efficiency and good polishing quality.

It should also be appreciated that while the present invention has been disclosed in the context of a preferred embodiment, the above embodiments are not intended to limit the invention. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the technology, or the technology can be modified to be equivalent. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A polishing method, comprising:

Providing a substrate;

2. The polishing method as recited in claim 1 wherein the plurality of beams of fluid flow against and/or parallel to the substrate surface.

3. The method of claim 1, wherein the plurality of beams of fluid are ejected in the same direction along the substrate surface, or wherein portions of the beams of fluid are ejected in different directions along the substrate surface.

4. The method of claim 1, wherein the substrate is heated prior to or during polishing the surface of the substrate with the plurality of beams of fluid.

5. The method of claim 4, wherein the substrate has a temperature of less than or equal to 100 ℃.

6. The method of claim 1, wherein a baffle is used to regulate the pressure of the fluid relative to the surface of the substrate during polishing of the surface of the substrate with the plurality of beams of fluid; wherein, the baffle is located above the substrate, and the interval range with the substrate surface is: 1 mm-10 mm.

7. The method of claim 1, wherein the substrate surface has at least a protruding structure and a dimple, and wherein during polishing of the substrate surface with the plurality of beams of fluid, the fluid removes the protruding structure and causes a cluster of the protruding structure to flow with the fluid to the dimple to fill the dimple.

8. The polishing method as recited in claim 1, wherein the substrate is rotated at a constant speed or a variable speed along the predetermined trajectory, and the rotation speed of the substrate is less than or equal to 1000rpm.

9. The polishing method according to any one of claims 1 to 8, wherein the fluid is a chemically non-reactive and abrasive-free liquid and/or gas, comprising: pure water, isopropanol, water vapor, organic vapor or inert gas.

10. A method for producing a semiconductor device, characterized by comprising the polishing method according to any one of claims 1 to 9.