WO2017185842A1

WO2017185842A1 - Focusing ring and plasma treatment device

Info

Publication number: WO2017185842A1
Application number: PCT/CN2017/072324
Authority: WO
Inventors: 李国荣
Original assignee: 北京北方微电子基地设备工艺研究中心有限责任公司
Priority date: 2016-04-26
Filing date: 2017-01-24
Publication date: 2017-11-02
Also published as: CN107316795B; CN107316795A; TW201805991A; TWI646573B

Abstract

Disclosed are a focusing ring (70) and a plasma treatment device. The inner diameter of the focusing ring is larger than the external diameter of an abutment (71), which matches with the focusing ring and is used for carrying a substrate (82). The focusing ring comprises a first annular step surface (72) and a second annular step surface (73), wherein both the first annular step surface and the second annular step surface are located on the side of the focusing ring facing the substrate, the second annular step surface is located inside of the first annular step surface and lower than the first annular step surface, and the second annular step surface is provided with a concave-convex structure. The focusing ring and the plasma treatment device can reduce the probability of the occurrence of adhesion between the substrate and a polymer, increase the stability during removing the substrate, and avoid the damage of a robot and the substrate. At the same time, the adhesion of a polymer to the back of the substrate can be reduced, thus reducing the contamination of the substrate caused by the polymer, improving the product quality, and reducing the contamination to a robot, a transport chamber and a substrate box caused by the polymer during the transfer process of the substrate.

Description

Focus ring and plasma processing device

Technical field

The present invention relates to the field of plasma processing technology, and in particular to a focus ring and a plasma processing apparatus.

Background technique

Plasma processing technology is widely used in the fabrication of integrated circuits (ICs) or MEMS devices. The plasma contains a large amount of active particles such as electrons, ions, excited atoms, molecules, and radicals. These active particles interact with the substrate to cause various physical and chemical reactions on the surface of the workpiece to be processed, such as a substrate. The reaction causes a change in the surface properties of the workpiece to be processed.

1 is a schematic view showing the structure of a plasma reaction chamber in the prior art; FIG. 2 is a schematic view showing the structure in the dotted line frame of FIG. 1; FIG. 3 is a schematic view showing the positional relationship between the wafer and the electrostatic chuck in a state in which the thimble is raised; 4 is a schematic view showing aggregation of atomic groups; and FIG. 5 is a schematic view showing aggregation of atomic groups in a state of raising a needle.

Referring to FIG. 1 to FIG. 5 together, the plasma reaction chamber includes a cavity 1 , a dielectric window 11 is disposed above the cavity 1 , and a nozzle 3 is disposed at a substantially central position of the dielectric window 11 , and the induction coil 2 is disposed The medium window 11 is connected to the first RF power source. The electrostatic chuck 4 is located in the reaction chamber defined by the cavity 1 and the dielectric window 11 and is connected to the second RF power source. The electrostatic chuck 4 is fixed to the substrate 5 placed thereon by the principle of electrostatic adsorption. The focus ring 6 is sleeved around the electrostatic chuck 4, and includes an upper stepped surface 61 and a lower stepped surface 62 for limiting the substrate 5 and localizing the plasma distributed at the edge portion of the substrate 5. Control ensures the process uniformity of the substrate 5.

Further, the plasma reaction chamber is further provided with a ejector mechanism 7, a ejector pin 8, and a thimble passage for the ejector pin 8 to move up and down is provided in the electrostatic chuck 4. Thimble movement mechanism 7 can drive the thimble 8 to move up and down along the axial direction of the electrostatic chuck 4, for example, driving the ejector pin 8 to lower the substrate 5 on the electrostatic chuck 4, or driving the thimble 8 to rise to disengage the substrate 5 from the electrostatic chuck 4 And it is raised to the take-up/release position so that the robot removes the substrate 5 or places it on the ejector pin 8.

During the plasma process, some of the atomic groups 9 collide with the focus ring 6 due to the poor directivity of the movement of the atomic group 9, so that some of the atomic groups 9 are on the edge of the back surface of the substrate 5 and the lower step surface of the focus ring 6. The enrichment between 62 produces a polymer 10 which is capable of exerting a certain adsorption on the substrate 5 and its packing position is not fixed. Thus, when the ejector pin 8 is lifted up from the substrate 5 after the completion of the process, due to the uneven adsorption of the polymer 10, the substrate 5 may be lifted up on one side, and even a sticking or offset may occur. This causes the substrate 5 and the robot to be scratched, causing the robot to be damaged or causing the substrate 5 to fail to be properly transmitted or damaged. Moreover, some polymers 10 are also adhered to the back surface of the substrate 5, which not only causes contamination of the substrate 5 itself but affects the quality of the product, but also affects the robot and the transfer chamber as the substrate 5 flows. The chamber and the substrate case cause pollution.

Summary of the invention

The present invention is directed to the above technical problems existing in the prior art, and provides a focus ring and a plasma processing apparatus. The focus ring can reduce the probability of adhesion of the substrate to the polymer, increase the stability of the substrate taking process, avoid damage of the robot or the substrate, and reduce the adhesion of the polymer on the back side of the substrate, thereby reducing The substrate is contaminated by the polymer, improving the quality of the product, and reducing the contamination of the polymer on the robot, the transfer chamber, and the substrate during the substrate transfer process.

The present invention provides a focus ring having an inner diameter larger than an outer diameter of a base for supporting a substrate, the focus ring including a first annular step surface and a second annular step surface, the first annular step The face and the second annular step face are both located on a side of the focus ring facing the substrate, and the second annular step face is located inside the first annular step face and is low And forming a first annular step surface, and the second annular step surface is provided with a concave-convex structure.

Wherein the concave-convex structure comprises a concave portion and a convex portion, and the concave portion and the convex portion are staggered with each other.

Wherein the recessed portion and the raised portion are each uniformly distributed on the second annular stepped surface.

The ratio of the occupied area of the recessed portion on the second annular stepped surface to the occupied area of the raised portion on the second annular stepped surface is greater than 1:1 and less than 20:1.

The cut surface shape of the recessed portion obtained by cutting the recessed portion along a radial direction of the second annular stepped surface includes a rectangular shape, a semicircular shape, a trapezoidal shape, a square shape or an inverted triangle shape; The longitudinal section shape of the convex portion obtained by cutting the convex portion in the radial direction of the step surface includes a rectangular shape, a semicircular shape, a trapezoidal shape, a square shape, or an inverted triangle shape.

Wherein the second annular step surface and the first annular step surface are parallel to the bearing surface of the base mated thereto, and the second annular step surface is lower than the bearing surface of the base.

Wherein the outer diameter of the second annular step surface is larger than the diameter of the substrate.

Wherein the first annular step surface is higher than the bearing surface of the base.

The material of the focus ring is the same as the material of the substrate.

As another technical solution, the present invention also provides a plasma processing apparatus including a base for carrying a substrate and a focus ring provided by any of the above aspects of the present invention, the focus ring being sleeved on the base The periphery.

Advantageous Effects of Invention: The focus ring provided by the present invention can reduce the polymerization deposited between the back edge of the substrate and the second annular step surface during the plasma treatment by providing the uneven structure on the second annular step surface. The adsorption of the substrate on the substrate reduces the probability of adhesion between the substrate and the polymer, thereby increasing the stability of the substrate taking process, avoiding the damage of the robot or the substrate, and reducing the polymer on the back of the substrate. Adhesion reduces the contamination of the substrate due to the polymer, improves product quality, and reduces contamination of the robot, the transfer chamber, and the substrate cassette during substrate transfer.

The plasma processing apparatus provided by the present invention can reduce the probability of adhesion between the substrate and the polymer by using the above-mentioned focus ring, increase the stability of the substrate taking process, and avoid damage of the robot or the substrate; It can reduce the adhesion of the polymer on the back side of the substrate, reduce the contamination of the substrate due to the polymer, improve the product quality, and reduce the polymer to the robot, the transfer chamber, and the substrate cassette during the substrate transfer process. The pollution caused.

DRAWINGS

1 is a schematic structural view of a plasma reaction chamber in the prior art;

Figure 2 is a schematic view showing the structure inside the broken line frame of Figure 1;

3 is a schematic view showing the positional relationship between the wafer and the electrostatic chuck in a state in which the thimble is raised;

Figure 4 is a schematic view showing the aggregation of atomic groups;

Figure 5 is a schematic view showing the aggregation of atomic groups in a needle-up state;

Figure 6 is a top plan view of the focus ring and the mating base provided by the present invention;

Figure 7 is a cross-sectional view showing a convex portion obtained by cutting a convex portion along a radial direction of a second annular step surface;

8 is a schematic view showing a dimensional relationship and an arrangement relationship of a convex portion and a concave portion;

Figure 9 is a schematic view showing the positional relationship between the focus ring and the base and the substrate.

detailed description

In order to enable those skilled in the art to better understand the technical solutions of the present invention, a focus ring and plasma processing apparatus provided by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1:

This embodiment provides a focus ring that is applied to a reaction chamber of a plasma processing apparatus and mounted in cooperation with a base for carrying a substrate. Specifically, as shown in Figures 6 to 9 As shown, the inner diameter of the focus ring 70 is larger than the outer diameter of the base 71, and the focus ring 70 is sleeved on the outer side of the base 71. The focus ring 70 includes a first annular step surface 72 and a second annular step surface 73. The first annular step surface 72 and the second annular step surface 73 are both located on a side of the focus ring 70 facing the substrate 82, and the second annular step The face 73 is located on the inner side of the first annular stepped surface 72 and is lower than the first annular stepped surface 72. The second annular stepped surface 73 is provided with a concave-convex structure.

During the plasma treatment, the polymer generated by the enrichment of the atomic group is deposited in the concavo-convex structure on the second annular step surface 73, because the distance between the polymer deposited on the recessed portion and the substrate 82 is higher. Large, its adsorption effect on the substrate 82 is small; and the distance between the polymer deposited on the convex portion and the substrate 82 is small, and the adsorption effect on the substrate 82 is large. That is, the adsorption of the polymer on the substrate 82 mainly comes from the polymer deposited on the convex portion, that is, a part of the second annular step surface 73 (the convex portion) has a strong adsorption to the substrate 82. effect. Since the convex portion is a part of the second annular step surface 73, the focus ring 70 provided by the present embodiment can reduce the deposition on the back edge of the substrate 82 during plasma processing, compared to the prior art. The adsorption of the polymer between the second annular step faces 73 on the substrate 82 reduces the probability of the substrate 82 sticking to the polymer, thereby increasing the stability of the substrate 82 during the film taking process, and avoiding the presence of the robot or substrate 82. The damage can also reduce the adhesion of the polymer on the back side of the substrate 82, reduce the contamination of the substrate 82 due to the polymer, improve the quality of the product, and reduce the flow of the polymer during the substrate 82. Contamination caused by robots, transfer chambers, and substrate cassettes.

Specifically, the uneven structure in the present embodiment includes a recessed portion 732 and a raised portion 731 which are disposed on the second annular stepped surface 73, and the recessed portion 732 and the raised portion 731 are alternately distributed with each other. The staggered distribution means that the periphery of the convex portion 731 is the concave portion 732, and the periphery of the concave portion 732 is the convex portion 731, and the specific positional relationship between the two is not limited. The recess 732 is disposed such that the polymer deposited therein is further away from the substrate 82, thereby impairing the adsorption of the substrate 82.

Preferably, the recessed portion 732 is evenly distributed on the second annular stepped surface 73, and The bosses 731 are evenly distributed on the second annular step surface 73. With this arrangement, the electric field applied to the edge region of the base 71 can be evenly distributed, so that the plasma distribution corresponding to the edge region of the substrate 82 during processing is uniform, thereby ensuring uniformity of processing of the edge region of the substrate 82.

Preferably, the ratio of the occupied area of the recessed portion 732 on the second annular stepped surface 73 to the occupied area of the raised portion 731 on the second annular stepped surface 73 is greater than 1:1 and less than 20:1. That is, the occupied area of the recessed portion 732 is larger than the occupied area of the raised portion 731, so that the polymer deposited between the back edge of the substrate 82 and the second annular stepped surface 73 during processing can be mostly gathered in the depressed portion. In 732, only a small portion is gathered on the surface of the convex portion 731, so that only a small portion of the polymer collected on the surface of the convex portion 731 is in contact with the back edge of the substrate 82, and most of the aggregates are concentrated in the depressed portion 732. The polymer does not contact the back edge of the substrate 82, thereby reducing the contact area of the polymer with the backside edge of the substrate 82, thereby reducing the adsorption of the polymer on the back side of the substrate 82.

In this embodiment, the shape of the cut surface of the convex portion 731 obtained by cutting the convex portion 731 along the radial direction of the second annular step surface 73 is a rectangle; the concave portion along the radial direction of the second annular step surface 73 The shape of the cut surface of the depressed portion 732 obtained by cutting in 732 is a rectangle. In a practical application, the shape of the cut surface of the recessed portion 732 obtained by cutting the recessed portion 732 along the radial direction of the second annular stepped surface 73 may also be other shapes such as semicircular, trapezoidal, square or inverted triangle; The shape of the cut surface of the convex portion 731 obtained by cutting the convex portion 731 in the radial direction of the second annular step surface 73 may be other shapes such as a semicircle, a trapezoid, a square, or an inverted triangle. In fact, the specific shape of the depressed portion 732 and the raised portion 731 may not be limited as long as the concave portion 732 and the convex portion 731 on the second annular stepped surface 73 are uniformly distributed.

In the present embodiment, the second annular step surface 73 and the first annular step surface 72 are parallel to the bearing surface 81 of the carrier substrate 82 of the base 71, and the second annular step surface 73 is lower than the bearing surface 81 of the base 71. So that the focus ring 70 is formed in an annular groove as a whole, and can be placed on the base 71. The substrate 82 on the bearing surface 81 serves as a position defining function to position the substrate 82 on the base 71 in a region defined by the second annular step surface 73, thereby causing the substrate 82 and the base 71. The relative position is more accurate and fixed while also ensuring that the substrate 82 does not slip laterally. Further, the height of the second annular step surface 73 is slightly lower than the bearing surface 81 of the base 71, so that the substrate 82 can be brought into contact with the bearing surface 81 of the base 71 so that the bearing surface 81 of the base 71 is opposed to the base. Sheet 82 is subjected to stable adsorption to ensure stability of substrate 82 during processing.

In the present embodiment, the outer diameter of the second annular stepped surface 73 is larger than the diameter of the substrate 82. In the actual design, the outer diameter of the second annular step surface 73 is slightly larger than the diameter of the substrate 82, so that the position of the substrate 82 on the base 71 can be well controlled, and the substrate 82 is placed on the base 71. The accuracy of the relative position on the bearing surface 81 and the accumulation of polymer on the second annular step surface 73 can be reduced.

In the present embodiment, the first annular step surface 72 is higher than the bearing surface 81 of the base 71. With this arrangement, the focus ring 70 having an annular groove-like structure as a whole can form a fence at the periphery of the base 71, thereby forming a certain maintenance effect on the uniform distribution of the electric field at the edge of the base 71, thereby causing the substrate 82 to be processed during the process. The plasma distribution in the edge regions remains uniform, thereby ensuring uniformity of processing of the substrate 82.

In the present embodiment, the material of the focus ring 70 is the same as the material of the substrate 82. For example, the focus ring 70 and the substrate 82 are made of quartz, so that the arrangement of the focus ring 70 does not introduce impurities during the processing of the substrate 82, thereby ensuring the quality of the process.

Advantageous Effects of Embodiment 1 : The focus ring provided in Embodiment 1 can reduce the deposition on the back edge of the substrate and the second annular step surface during the plasma treatment by providing the uneven structure on the second annular step surface. The adsorption of the polymer on the substrate reduces the probability of adhesion between the substrate and the polymer, thereby increasing the stability of the substrate taking process, avoiding the damage of the robot or the substrate, and reducing the polymer base. Adhesion on the back side of the sheet reduces the contamination of the substrate due to the polymer, improves product quality, and reduces the polymer at the base Contamination of the robot, the transfer chamber, and the substrate cassette during the subsequent transfer of the sheet.

Example 2:

The present embodiment provides a plasma processing apparatus including a base for carrying a substrate, and a focus ring provided by the foregoing embodiment of the present invention, and the focus ring is sleeved on the periphery of the base. In practical applications, the plasma processing apparatus may include a plasma etching apparatus or the like.

The plasma processing apparatus provided by the present invention can reduce the probability of adhesion between the substrate and the polymer by using the focus ring provided by the foregoing embodiments of the present invention, increase the stability of the substrate taking process, and avoid the occurrence of the robot or the substrate. Damage; at the same time, it can reduce the adhesion of the polymer on the back side of the substrate, reduce the contamination of the substrate due to the polymer, improve the quality of the product, and reduce the polymer to the robot and the transfer chamber during the substrate transfer process. , the contamination caused by the substrate box.

It is to be understood that the above embodiments are merely exemplary embodiments employed to explain the principles of the invention, but the invention is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the invention. These modifications and improvements are also considered to be within the scope of the invention.

Claims

A focus ring having an inner diameter greater than an outer diameter of a base for supporting a substrate, the focus ring including a first annular step surface and a second annular step surface, the first annular step surface and The second annular step surface is located on a side of the focus ring facing the substrate, and the second annular step surface is located inside the first annular step surface and lower than the first annular step surface And characterized in that the second annular step surface is provided with a concave-convex structure.
The focus ring according to claim 1, wherein the uneven structure includes a concave portion and a convex portion, and the concave portion and the convex portion are staggered with each other.
The focus ring according to claim 2, wherein said recessed portion and said raised portion are each evenly distributed on said second annular stepped surface.
The focus ring according to claim 2, wherein a ratio of an occupied area of the recessed portion on the second annular stepped surface to an occupied area of the raised portion on the second annular stepped surface Greater than 1:1 and less than 20:1.
The focus ring according to claim 2, wherein the shape of the cut surface of the recessed portion obtained by cutting the recessed portion in the radial direction of the second annular stepped surface comprises a rectangular shape, a semicircular shape , trapezoidal, square or inverted triangle;

The shape of the cut surface of the convex portion obtained by cutting the convex portion along the radial direction of the second annular step surface includes a rectangle, a semicircle, a trapezoid, a square, or an inverted triangle.
The focus ring according to claim 1, wherein said second annular step surface and said first annular step surface are parallel to a bearing surface of said base mated thereto, and said second annular step The surface is lower than the bearing surface of the base.
The focus ring of claim 6 wherein said second annular stepped surface has an outer diameter greater than a diameter of said substrate.
The focus ring of claim 6 wherein said first annular step surface is higher than a bearing surface of said base.
The focus ring according to claim 1, wherein the material of the focus ring is the same as the material of the substrate.
A plasma processing apparatus comprising a base for carrying a substrate, characterized by further comprising the focus ring of any one of claims 1-9, the focus ring being sleeved on a periphery of the base .