TWI646573B - Focusing ring and plasma processing device - Google Patents

Abstract

The invention provides a focusing ring and a plasma processing device. The inner diameter of the focusing ring is larger than the outer diameter of the base for supporting the wafer. The focusing ring includes a first annular step surface and a second annular step surface, a first annular step surface and a second annular step. The surfaces are located on the side of the focusing ring facing the wafer, the second annular stepped surface is located inside the first annular stepped surface and lower than the first annular stepped surface, and a concave-convex structure is provided on the second annular stepped surface. The focusing ring and the plasma processing device can reduce the probability of adhesion between the wafer and the polymer, increase the stability of the wafer picking process, avoid the damage of the manipulator or the wafer, and reduce the adhesion of the polymer on the back of the wafer. , Reduce the pollution caused by the polymer to the wafer, improve the product quality, and reduce the polymer's pollution to the manipulator, the transfer chamber, and the wafer box during the wafer transfer process.

Description

Focusing ring and plasma processing device

The invention relates to the technical field of plasma processing, in particular to a focusing ring and a plasma processing device.

Plasma processing technology is widely used in the fabrication of integrated circuit (IC) or MEMS devices. Among them, the plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules, and free 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 wafers. Changes in the surface properties of the workpiece to be processed.

Figure 1 is a schematic diagram of the structure of a plasma reaction chamber in the prior art; Figure 2 is a schematic diagram of the structure within the dashed frame in Figure 1; Figure 3 is the positional relationship between the wafer and the electrostatic chuck in a state where the ejector pin is raised Schematic diagram; Fig. 4 is a diagram showing the aggregation of atomic groups; and Fig. 5 is a diagram showing the aggregation of atomic groups in a needle-up state.

Please refer to FIGS. 1 to 5 together. The plasma reaction chamber includes a cavity 1. A dielectric window 11 is provided above the cavity 1, and a nozzle is provided at a substantially center position of the dielectric window 11. 3. The induction coil 2 is placed on the dielectric window 11 and is connected to the first radio frequency 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 a second radio frequency power source. The electrostatic chuck 4 uses the principle of electrostatic adsorption to fix the wafer 5 placed thereon. The focusing ring 6 is sleeved around the electrostatic chuck 4 and includes an upper step surface 61 and a lower step surface 62 to limit the position of the wafer 5 and to locally control the plasma distributed on the edge portion of the wafer 5, The uniformity of the process of the wafer 5 is ensured.

In addition, the plasma reaction chamber is also provided with a thimble movement mechanism 7 and a thimble 8, and a thimble channel for the up and down movement of the thimble 8 is provided in the electrostatic chuck 4. The ejector pin moving mechanism 7 can drive the ejector pin 8 to move up and down along the axis of the electrostatic chuck 4, for example, the ejector pin 8 can be lowered to place the wafer 5 on the electrostatic chuck 4, or the ejector pin 8 can be raised to disengage the wafer 5 from the electrostatic chuck 4 and rise to the pick / place position, so that the robot 5 removes the wafer 5 or places it on the ejector pin 8.

During the plasma manufacturing process, because the directionality of the atomic group 9 is poor, some atomic groups 9 will collide with the focusing ring 6, so that some of the atomic groups 9 are on the back edge of the wafer 5 and the lower step surface 62 of the focusing ring 6. Inter-enrichment results in a polymer 10, which can produce a certain adsorption effect on the wafer 5 and its stacking position is not fixed. In this way, when the ejector pin 8 lifts up the wafer 5 after the process is completed, due to the uneven adsorption of the polymer 10, the wafer 5 may be lifted on one side, and even the sticking or offset may occur, which will cause the wafer Scratching between the robot 5 and the robot causes damage to the robot or the wafer 5 cannot be transferred out or damaged normally. In addition, some polymers 10 will be adhered to the back of the wafer 5, which will not only pollute the wafer 5 itself and affect the product quality, but also affect the manipulator, the transfer chamber, and the wafer as the wafer 5 flows. Boxes cause pollution.

The present invention is directed to the aforementioned technical problems in the prior art, and provides a focusing ring and a plasma processing device. The focusing ring can reduce the chance of adhesion between the wafer and the polymer, increase the stability of the wafer picking process, and avoid the damage of the robot or the wafer; at the same time, it can reduce the adhesion of the polymer on the back of the wafer and reduce the risk of the wafer. Pollution caused by polymers, improving product quality, and reducing pollution caused by the polymer to robots, transfer chambers, and wafer cassettes during wafer transfer.

The present invention provides a focusing ring having an inner diameter larger than an outer diameter of a base for supporting a wafer. The focusing ring includes a first annular step surface and a second annular step surface. The first annular step surface And the second annular step surface are located on the side of the focusing ring facing the wafer, the second annular step surface is located inside the first annular step surface, and is lower than the first annular step surface, and the An uneven structure is provided on the second annular step surface.

The concave-convex structure includes concave portions and convex portions, and the concave portions and the convex portions are staggered and distributed with each other.

Wherein, the concave portion and the convex portion are each evenly distributed on the second annular step surface.

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

The cut shape of the recessed portion obtained by cutting the recessed portion in a radial direction of the second annular stepped surface includes a rectangle, a semicircle, a trapezoid, a square or an inverted triangle; The shape of the longitudinal section of the raised portion obtained by cutting the raised portion includes a rectangle, a semicircle, a trapezoid, a square, or an inverted triangle.

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

The outer diameter of the second annular stepped surface is larger than the diameter of the wafer.

The first annular step surface is higher than the bearing surface of the abutment.

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

As another technical solution, the present invention further provides a plasma processing apparatus, which includes a base for carrying a wafer and a focusing ring provided by any one of the above solutions of the present invention, the focusing ring is sleeved around the base.

Advantageous effects of the present invention: By providing a concavo-convex structure on the second annular step surface of the focusing ring provided by the present invention, the polymer deposited between the back edge of the wafer and the second annular step surface during plasma processing can be reduced. The adsorption of the wafer reduces the chance of adhesion between the wafer and the polymer, thereby increasing the stability of the wafer picking process and avoiding damage to the robot or the wafer; at the same time, it can reduce the adhesion of the polymer on the back of the wafer and reduce Pollution of the wafer due to the polymer improves the quality of the product and reduces the pollution of the polymer to the manipulator, the transfer chamber, and the wafer box during the wafer transfer process.

The plasma processing device provided by the present invention can also reduce the probability of adhesion between the wafer and the polymer by using the above-mentioned focus ring, increase the stability of the wafer picking process, and avoid the damage of the robot or the wafer; Reduce the adhesion of the polymer on the back of the wafer, reduce the pollution caused by the polymer to the wafer, improve the product quality, and reduce the pollution of the polymer to the manipulator, the transfer chamber, and the wafer box during the wafer transfer process.

1‧‧‧ cavity

2‧‧‧ induction coil

3‧‧‧ Nozzle

4‧‧‧ electrostatic chuck

5.82‧‧‧chip

6, 70‧‧‧ focus ring

7‧‧‧ thimble movement mechanism

8‧‧‧ thimble

9‧‧‧ atomic group

10‧‧‧ Polymer

11‧‧‧ Dielectric window

61, 62‧‧‧step surface

71‧‧‧ abutment

72, 73‧‧‧ annular step surface

731‧‧‧ raised

732‧‧‧Depression

81‧‧‧bearing surface

Figure 1 is a schematic diagram of the structure of a plasma reaction chamber in the prior art; Figure 2 is a schematic diagram of the structure within the dashed frame in Figure 1; Figure 3 is the positional relationship between the wafer and the electrostatic chuck in a state where the ejector pin is raised Schematic diagram; Fig. 4 is a schematic diagram showing the aggregation of atomic groups; Fig. 5 is a schematic diagram showing the aggregation of atomic groups in the needle-up state; FIG. 8 is a schematic view showing a dimensional relationship and an arrangement relationship between the convex portion and the concave portion; FIG. 8 is a schematic view showing a positional relationship between the focus ring and the base and the wafer.

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

Example 1:

This embodiment provides a focusing ring, which is used in a reaction chamber of a plasma processing apparatus and is installed in cooperation with a base for carrying a wafer. Specifically, as shown in FIGS. 6 to 8, 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 outside 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 the side of the focus ring 70 facing the wafer 82. The step surface 73 is located inside the first ring-shaped step surface 72 and is lower than the first ring-shaped step surface 72. A concave-convex structure is provided on the second ring-shaped step surface 73.

During the plasma processing, the polymer produced by the enrichment of the atomic groups will be deposited in the uneven structure on the second annular stepped surface 73, and the distance between the polymer deposited in the recessed portion and the wafer 82 is large. Its adsorption effect on the wafer 82 is small; while the distance between the polymer deposited on the convex portion and the wafer 82 is small, its adsorption effect on the wafer 82 is large. That is, the polymer's adsorption effect on the wafer 82 mainly comes from the polymer deposited on the convex portion, that is, a portion (the convex portion) in the second annular stepped surface 73 has a strong adsorption effect on the wafer 82. Since the raised portion is a part of the second annular stepped surface 73, compared with the prior art, the focus ring 70 provided in this embodiment can reduce the deposition on the back edge of the wafer 82 and the second edge during the plasma processing. The adsorption effect of the polymer between the annular step surfaces 73 on the wafer 82 reduces the chance of the wafer 82 adhering to the polymer, thereby increasing the stability of the wafer 82 fetching process and avoiding the damage of the manipulator or the wafer 82; It can also reduce the adhesion of the polymer to the back of the wafer 82, reduce the pollution caused by the polymer to the wafer 82, improve the product quality, and reduce the polymer to the manipulator, the transfer chamber, and the wafer during the flow of the wafer 82 Pollution caused by boxes.

Specifically, the concave-convex structure in this embodiment includes concave portions 732 and convex portions 731 provided on the second annular stepped surface 73, and the concave portions 732 and convex portions 731 are staggered and distributed with each other. The staggered distribution means that the periphery of the convex portion 731 is a recessed portion 732 and the periphery of the recessed portion 732 is a raised portion 731, and the specific positional relationship between the two is not limited. The arrangement of the depression 732 enables deposition The polymer therein is far from the wafer 82, thereby weakening the adsorption effect on the wafer 82.

Preferably, the concave portions 732 are uniformly distributed on the second annular step surface 73, and the convex portions 731 are uniformly distributed on the second annular step surface 73. In this way, the electric field applied to the edge region of the base 71 can be uniformly distributed, so that the plasma distribution corresponding to the edge region of the wafer 82 during processing is uniform, and the uniformity of the edge region processing of the wafer 82 can be ensured.

Preferably, the ratio of the occupied area of the concave portion 732 on the second annular step surface 73 to the occupied area of the convex portion 731 on the second annular step 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. This arrangement enables the majority of the polymer deposited between the back edge of the wafer 82 and the second annular stepped surface 73 to accumulate in the recessed portion 732 during processing. Only a small portion of the polymer aggregates on the surface of the convex portion 731, so that only a small portion of the polymer accumulated on the surface of the convex portion 731 contacts the back edge of the wafer 82, and most of the polymer accumulated in the concave portion 732 It is not in contact with the back edge of the wafer 82, thereby reducing the contact area between the polymer and the back edge of the wafer 82, and further reducing the adsorption of the polymer to the back of the wafer 82.

In this embodiment, the shape of the cut surface of the raised portion 731 obtained by cutting the raised portion 731 along the radial direction of the second annular stepped surface 73 is rectangular; the recessed portion is formed along the radial direction of the second annular stepped surface 73. The shape of the cut surface of the recessed portion 732 obtained by cutting 732 is rectangular. In practical applications, 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; Ground, the shape of the cut surface of the raised portion 731 obtained by cutting the raised portion 731 along the radial direction of the second annular stepped surface 73 may also be other shapes such as a semicircle, a trapezoid, a square, or an inverted triangle. In fact, the specific shapes of the concave portions 732 and the convex portions 731 may not be limited as long as the concave portions 732 and the convex portions 731 on the second annular step surface 73 can be ensured to be uniformly distributed.

In this embodiment, the second annular step surface 73 and the first annular step surface 72 are parallel to the bearing surface 81 of the carrier wafer 82 of the base 71, and the second annular step surface 73 is lower than the bearing surface of the base 71 81. In this way, the focus ring 70 is formed into an annular groove as a whole, which can limit the position of the wafer 82 placed on the bearing surface 81 of the base 71, and the position of the wafer 82 on the base 71 is restricted to the second position. Within the area surrounded by the annular step surface 73, the relative position of the wafer 82 and the base 71 is more accurate and fixed, and at the same time, it is ensured that the wafer 82 does not slip laterally. In addition, the height of the second annular stepped surface 73 is slightly lower than the bearing surface 81 of the base 71. In this way, the wafer 82 can be attached to the bearing surface 81 of the base 71 so that the bearing surface 81 of the base 71 faces the wafer 82. Stable adsorption is performed to ensure the stability of the wafer 82 during processing.

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

In this embodiment, the first annular step surface 72 is higher than the bearing surface 81 of the base 71. In this way, the focusing ring 70 having an annular groove structure as a whole can form a fence around 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, so that the edge of the wafer 82 is processed during the process The plasma distribution in the area remains uniform, thereby ensuring the uniformity of wafer 82 processing.

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

Advantageous effect of Embodiment 1: The focusing ring provided in Embodiment 1 can reduce the deposition between the back edge of the wafer and the second annular stepped surface during the plasma processing by providing a concave-convex structure on the second annular stepped surface. The adsorption of the polymer on the wafer reduces the chance of adhesion between the wafer and the polymer, thereby increasing the stability of the wafer picking process and avoiding damage to the robot or the wafer; at the same time, it can reduce the polymer on the back of the wafer. Adhesion reduces the wafer due to the polymerization Pollution caused by materials, improve product quality, and reduce the pollution of the polymer to the manipulator, the transfer chamber, and the wafer box during the subsequent flow of the wafer.

Example 2:

This embodiment provides a plasma processing apparatus, which includes a base for carrying a wafer, and a focus ring provided by the foregoing embodiment of the present invention, and the focus ring is sleeved around the base. In practical applications, the plasma processing apparatus may include a plasma etching apparatus and the like.

The plasma processing device provided by the present invention can reduce the probability of adhesion between the wafer and the polymer by using the focus ring provided by the foregoing embodiment of the present invention, increase the stability of the wafer fetching process, and avoid the damage of the manipulator or the wafer. ; At the same time, it can reduce the adhesion of the polymer on the back of the wafer, reduce the pollution caused by the polymer to the wafer, improve the product quality, and reduce the polymer caused to the manipulator, the transfer chamber, and the wafer box during the wafer transfer process. Pollution.

It can be understood that the above embodiments are merely exemplary embodiments used to explain the principle of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various variations and improvements can be made without departing from the spirit and essence of the present invention, and these variations and improvements are also considered as the protection scope of the present invention.

Claims (10)

A focusing ring having an inner diameter larger than an outer diameter of a base for supporting a wafer with which the focusing ring includes a first annular step surface and a second annular step surface, the first annular step Both the surface and the second annular step surface are located on the side of the focusing ring facing the wafer. The second annular step surface is located inside the first annular step surface and is lower than the first annular step surface. It is characterized in that a concave-convex structure is provided on the second annular stepped surface, the concave-convex structure includes a concave portion and a convex portion, and the concave-convex structure is arranged such that the polymer deposited in the concave portion and the The distance between the lower surface of the wafer is greater than the distance between the polymer deposited by the protrusion and the lower surface of the wafer. The focusing ring according to item 1 of the scope of patent application, wherein the recessed portions and the protruding portions are staggeredly distributed with each other. The focusing ring according to item 2 of the scope of patent application, wherein the recessed portion and the protruding portion are each evenly distributed on the second annular step surface. The focusing ring according to item 2 of the scope of patent application, wherein the ratio of the occupied area of the recessed portion on the second annular step surface to the occupied area of the raised portion on the second annular step surface is greater than 1: 1 and less than 20: 1. The focusing ring according to item 2 of the scope of patent application, wherein a shape of a cut surface of the recessed portion obtained by cutting the recessed portion in a radial direction of the second annular stepped surface includes a rectangle, a semicircle, and a trapezoid. , A square, or an inverted triangle; a shape of a cut surface of the convex portion obtained by cutting the convex portion along a radial direction of the second annular stepped surface includes a rectangle, a semicircle, a trapezoid, a square, or an inverted triangle. The focusing ring according to item 1 of the scope of patent application, wherein the second annular step surface and the first annular step surface are parallel to the bearing surface of the abutment mated with the second annular step surface and the second annular step surface is low On the bearing surface of the abutment. The focusing ring according to item 6 of the patent application scope, wherein an outer diameter of the second annular stepped surface is larger than a diameter of the wafer. The focusing ring according to item 6 of the patent application scope, wherein the first annular step surface is higher than the bearing surface of the abutment. The focusing ring according to item 1 of the scope of patent application, wherein the material of the focusing ring is the same as that of the wafer. A plasma processing apparatus includes a base for carrying a wafer, and further includes a focusing ring according to any one of claims 1 to 9 of a patent application scope, the focusing ring being sleeved on the base of the base. Surrounding.