TWI672725B - Process chamber and capacitively coupled plasma device - Google Patents

Abstract

The disclosure provides a process chamber and a capacitive coupling plasma device. The process chamber includes a chamber body, a lining, and a magnetic component. The inner lining is arranged in the chamber body to define a processing area for processing the wafer; the magnetic component is arranged outside the processing area, and the magnetic field generated can reduce the etching rate of the edge area and the center area of the wafer during the wafer processing process. gap.

Description

Process chamber and capacitive coupling plasma device

The disclosure relates to the technical field of semiconductor manufacturing, and in particular, to a process chamber and a capacitive coupling plasma device.

In the semiconductor etching process, the etching uniformity of the wafer is an important technical index. In order to prevent the support disk from being etched to contaminate the wafer, the size of the lower electrode of the plasma etching apparatus is generally smaller than the wafer size. Therefore, there is an electric field at the edge of the wafer that is much higher than the central area, which results in a higher plasma density in the edge area, a large ion flux reaching the edge of the wafer, resulting in a high etching rate at the edge of the wafer, which seriously affects the etching uniformity of the wafer. This effect is called fringe electric field effect, and it is especially serious in the capacitive coupling plasma (CCP) etching device, and sometimes the etching rate of the wafer edge is even more than double the central area.

At present, the problem of the fringe electric field effect is mainly solved by a focus ring of a specific structure. The focus ring diameter is slightly larger than the wafer. The dielectric constant of the focus ring should be as large as possible, often using quartz crystal or ceramics, and the selected material should be compatible with the etching process. The focus ring of this structure can improve the distribution of the fringe electric field. The height and inner diameter of the focus ring can be adjusted to limit the ion flux reaching the edge of the wafer, thereby reducing the etching rate of the edge of the wafer.

However, in the process of implementing this disclosure, the applicant found that the prior art has the following defects: In the capacitive coupling plasma etching device, the electric field effect at the edge is very strong, and it is difficult to effectively solve the edge by increasing the height of the focus ring and adjusting the inner diameter of the focus ring. The problem is that the etching rate is too high; and if the height of the focus ring is too large, etching by-products are easily deposited on the inner side of the focus ring, thereby affecting the stability of the process.

The present disclosure aims to at least partially solve the technical problems in the prior art, and proposes a process chamber and a capacitive coupling plasma device.

According to an aspect of the present disclosure, there is provided a process chamber including: a chamber body; an inner liner disposed in the chamber body, the inner liner defining a process region for processing a wafer; and a magnetic component disposed in the process region In addition, the magnetic field generated by the magnetic component can reduce the difference in etching rate between the edge region and the center region of the wafer during the wafer processing process.

In some embodiments of the present disclosure, the magnetic component corresponds to the edge region of the wafer, so that the magnetic field generated by the magnetic component is distributed in the edge region of the wafer, so as to reduce the etching rate of the edge region of the wafer.

In some embodiments of the present disclosure, the magnetic component includes: an inner layer magnet and an outer layer magnet distributed in a radial direction; wherein the polarity of the inner layer magnet is opposite to that of the outer layer magnet.

In some embodiments of the present disclosure, the inner layer magnet and the outer layer magnet both have a ring structure.

In some embodiments of the present disclosure, the ring structure is formed by a plurality of cylindrical magnets arranged at equal intervals.

In some embodiments of the present disclosure, the ring structure is formed by a plurality of arc-shaped magnets arranged at equal intervals.

In some embodiments of the present disclosure, the ring structure is an integrally formed ring magnet.

In some embodiments of the present disclosure, the material of the magnetic component is N38SH or N40SH.

In some embodiments of the present disclosure, a diameter of the inner layer magnet is larger than a diameter of the wafer, and a radial distance between the inner layer magnet and the outer layer magnet is less than 30 mm.

In some embodiments of the present disclosure, a support assembly is further included, the support assembly includes a base and a focus ring, the focus ring is coupled to the base and surrounds an outer peripheral wall of the base, the base includes a support plate and an insulation Disk; the support disk is used to carry the wafer, and the insulation disk is used to insulate the support disk from the lining.

In some embodiments of the present disclosure, the inner lining includes a top lining and a bottom lining, and the top lining and the bottom lining together define a process area; the supporting component is disposed on a bottom wall of the lining facing away from the chamber body. The magnetic component is disposed on the surface of the backing facing the bottom wall of the chamber body, and the magnetic component corresponds to an edge region of the support component, so that the magnetic field is distributed on the edge portion of the base and the The area where the focus ring is located.

In some embodiments of the present disclosure, the diameter of the inner layer magnet is larger than the diameter of the wafer, and the radial distance between the inner layer magnet and the outer layer magnet is equal to the surface of the support disc facing away from the bottom wall of the chamber body and the bottom The vertical spacing of the surface of the liner facing the bottom wall of the chamber body.

According to another aspect of the present disclosure, a capacitive coupling plasma device is provided, including the above-mentioned process chamber.

In some embodiments of the present disclosure, the capacitive coupling plasma device is a capacitive coupling plasma pre-cleaning device.

By providing magnetic components corresponding to the edge region of the wafer, the present disclosure can effectively reduce the etching rate at the edge of the wafer, reduce the gap with the etching rate at the center of the wafer, thereby improving the etching uniformity of the wafer, and solving the problem of edge electric field effects. It will not cause the etching by-products to be deposited inside the focusing ring, which can ensure that the process is stable for a long time.

In order to make the objectives, technical solutions, and advantages of the disclosure more clear, the disclosure is further described in detail below with reference to specific embodiments and with reference to the accompanying drawings. It should be understood, however, that these descriptions are merely exemplary and are not intended to limit the scope of the disclosure. In addition, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

The embodiment of the present disclosure provides a process chamber, which can be applied to a capacitive coupling plasma device, and in particular, can be applied to a capacitive coupling plasma pre-cleaning device. As shown in FIG. 1, the process chamber 100 includes: a chamber The body 110, the lining 120, and the magnetic component 130.

As shown in FIG. 1, the chamber body 110 includes a side wall 111 and a bottom wall 112 connected to the side wall 111. The bottom wall 112 is provided with a suction port 112 a for discharging process gases and etching by-products. An inner liner 120 is disposed in the chamber body 110 to prevent the chamber body 110 from being corroded and corroded by plasma. The inner liner 120 defines a process area S for forming a processing wafer (not shown in the figure). The inner lining 120 may be a separate structure. As shown in FIG. 1, the inner lining 120 may include a bottom lining 121 and a top lining 122, and the top lining 122 and the bottom lining 121 together define a process region S. Of course, in addition to this, the lining 120 may have an integrated structure.

The magnetic component 130 is disposed outside the processing region S. For example, as shown in FIG. 1, the magnetic component 130 may be disposed below the processing region S. The magnetic component 130 can generate a magnetic field, and the magnetic field generated by the magnetic component 130 can reduce the difference in etching rate between the edge region and the center region of the wafer during the wafer processing process.

As documented in the prior art, there is an electric field in the edge area of the wafer that is much higher than the center area, which results in a higher plasma density in the edge area, a large ion flux reaching the edge of the wafer, and a high edge edge etching rate. , Which seriously affects the etching uniformity of the wafer. Therefore, the inventor has designed the structure of the process chamber 100 disclosed in the present disclosure, that is, a magnetic component 130 is disposed outside the process area S. For example, as shown in FIG. 1, the magnetic component 130 may be disposed in an edge area of a wafer. In this way, during the manufacturing process, the magnetic field generated by the magnetic component 130 is mainly distributed above and below the magnetic component 130, so that part of the plasma can be constrained in the distribution area of the magnetic field, and at the same time, it is difficult for the electric field component perpendicular to the magnetic field to be effective. Coupled into the plasma, the plasma density at the wafer edge decreases. The two factors mentioned above result in a decrease in the ion flux reaching the edge of the wafer, thereby reducing the etching rate at the edge of the wafer. At the same time, in the central area of the wafer, the magnetic field strength rapidly decays, which hardly affects the etching rate in the center of the wafer, thereby improving the uniformity of wafer etching.

As shown in FIG. 1, specifically, the magnetic component 130 may be disposed on a surface of the substrate 121 facing the bottom wall 112 of the chamber body 110. Preferably, the magnetic component 130 may correspond to an edge region of the wafer so that The magnetic field generated by the magnetic component 130 is distributed on the edge region of the wafer to reduce the etching rate of the edge region of the wafer.

Specifically, as shown in FIG. 1, the magnetic component 130 includes an inner layer magnet 131 and an outer layer magnet 132 distributed in a radial direction. The polarity of the inner layer magnet 131 is opposite to that of the outer layer magnet 132 so that a magnetic circuit can be formed between them. For example, as shown in FIG. 1, the S pole of the inner magnet 131 faces upward and the N pole faces downward. Accordingly, the S pole of the outer magnet 132 faces downward and the N pole faces upward. Of course, the S pole of the inner magnet 131 faces downward and the N pole faces upward. Accordingly, the S pole of the outer magnet 132 faces upward and the N pole faces downward.

Generally, the wafer has a circular structure. Therefore, in order to adapt to the structure of the wafer, both the inner layer magnet 131 and the outer layer magnet 132 have a ring structure.

As shown in FIG. 2, in this embodiment, the inner magnet 131 and the outer magnet 132 are both a plurality of (20 in the second figure) cylindrical magnets arranged at equal intervals and formed in a concentric ring structure. One end is fixed to the lower surface of the inner liner 120, and one end of the cylindrical magnet can be fixed to the lower surface of the backing 121, and should be in good contact with the lower surface of the backing 121 to prevent ignition. The polarities of all the cylindrical magnets of the inner magnet 131 are the same, the polarities of all the cylindrical magnets of the outer magnet 132 are the same, and the polarities of the cylindrical magnets of the inner magnet 131 and the outer magnet 132 are the same, so that the inner magnets have the same polarity. The magnet 131 and the outer magnet 132 form a magnetic circuit. In one example, the cylindrical magnet S pole of the inner magnet 131 is fixed upward on the lower surface of the backing 121 and N-level faces downward toward the bottom wall 112 of the chamber body; the cylindrical magnet S pole of the outer magnet 132 faces downward. The bottom wall 112 toward the chamber body is fixed to the lower surface of the bottom liner 121 in an N-level upward direction. In another example, the situation can also be reversed, that is, the cylindrical magnets of the inner magnet 131 face upwards with N poles facing downwards, and the cylindrical magnets of the outer layer magnet 132 face downwards with N poles facing upwards.

As shown in FIG. 3, the magnetic component 130 of this embodiment forms a magnetic field, and the magnetic field is mainly distributed above and below the magnetic component 130 and located between the inner layer magnet 131 and the outer layer magnet 132. Since the magnetic component 130 corresponds to the edge area of the wafer, the magnetic field above the magnetic component 130 is also distributed in the edge area of the wafer. During the manufacturing process, due to the magnetic field in the edge area of the wafer, part of the plasma will be constrained in the edge area. At the same time, it is difficult to effectively couple the electric field component perpendicular to the magnetic field to the plasma, and the plasma density at the edge of the wafer is reduced. The two factors mentioned above result in a decrease in the ion flux reaching the edge of the wafer, thereby reducing the etching rate at the edge of the wafer. At the same time, in a region far from the edge region of the wafer, that is, the central region of the wafer, the magnetic field strength rapidly decays, which hardly affects the etching rate in the center of the wafer, thereby improving the uniformity of wafer etching.

Optionally, the material of the magnetic component 130 is N38SH or N40SH. The magnetic component 130 of these materials can withstand a high temperature of 150 ° C. and can be used in a vacuum environment. The inner and outer magnets are located outside the process area. They are not in contact with the plasma and will not be corroded by the plasma pollution.

As shown in FIG. 2, the diameter W of the inner layer magnet 131 may be slightly larger than the diameter of the wafer, and the radial distance h between the inner layer magnet 131 and the outer layer magnet 132 may be less than 30 mm. Within the above-mentioned size range, the diameter W of the inner layer magnet 131 and the radial distance h between the inner layer magnet 131 and the outer layer magnet 132 can be adjusted. In addition, magnets with different magnetic field strengths can also be selected. By adjusting the diameter W of the inner layer magnet 131, the radial distance h between the inner layer magnet 131 and the outer layer magnet 132, and the magnetic field strength of the magnet, the etching rate of the wafer edge can be controlled.

As shown in FIG. 1, the process chamber 100 further includes a support assembly 140 including a base 141 and a focus ring 142. The focus ring 142 is coupled to the base 141 and surrounds an outer peripheral wall of the base 141. The base 141 includes a support plate 141a and an insulating plate 141b. The support plate 141a is used to support a wafer. The insulating disk 141 b is used to insulate the support disk 141 a from the lining 120. The focusing ring 142 prevents the wafer from sliding out of the support plate 141a, and restrains the plasma above the support assembly 140, and plays a role of suppressing the fringe electric field effect.

Specifically, as shown in FIG. 1, the support assembly 140 is disposed on a surface of the backing 121 facing away from the bottom wall 112 of the chamber body 110. More specifically, the insulating disk 141 b and the support disk 141 a are sequentially disposed on the backing 121. Top surface. The magnetic component 130 is disposed on the surface of the backing 121 facing the bottom wall 112 of the chamber body 110, and the magnetic component 130 corresponds to an edge region of the support component 140 so that the magnetic field is distributed on the edge portion of the base 141 and the focus ring. 142 area.

Specifically, as shown in FIG. 3, the radial distance h between the inner layer magnet 131 and the outer layer magnet 132 is approximately the distance between the support plate 141 a and the inner layer magnet 131, that is, from the upper surface of the support plate 141 a to the lower surface of the backing 121. The distance a, a is preferably less than 30 mm. Within the above-mentioned size range, the diameter W of the inner layer magnet 131 and the radial distance h between the inner layer magnet 131 and the outer layer magnet 132 can be adjusted. For example, in FIG. 3, the inner layer magnet 131 is located below the edges of the support plate 141a and the insulating plate 141b, and the outer layer magnet 132 is located below the focus ring 142. Alternatively, as shown in FIG. 1, the inner layer magnet 131 is located below the focusing ring 142 and the outer layer magnet 132 is located outside the focusing ring 142. The diameter W of the inner layer magnet 131 is larger than the diameter of the wafer. In addition, similarly, magnets with different magnetic field strengths can also be selected. By adjusting the diameter W of the inner magnet 131, the radial distance h between the inner magnet 131 and the outer magnet 132, and the magnetic field strength of the magnet, the etching rate of the wafer edge can be controlled. .

Generally, the supporting plate 141a can be made of metal, and aluminum is usually selected. In order to prevent the metal supporting disc 141a from being etched by the plasma and contaminating the wafer, the size of the supporting disc 141a is slightly smaller than the wafer, that is, the diameter of the supporting disc 141a is smaller than the diameter of the wafer. The insulating disk 141b may be made of an insulating material such as ceramic. Except for the support plate 141a, all other parts are in good contact with the ground.

In addition, as shown in FIG. 1, the supporting assembly 140 further includes a corrugated tube 143. The corrugated tube 143 is disposed between the bottom wall 112 and the base 121 of the chamber body 110 to support the base 121 and can drive the base. 121 lift.

In addition, as shown in FIG. 1, the process chamber 100 further includes a gas distribution plate 150, a matcher 160, and a radio frequency power supply 170. The air distribution plate 150 may be disposed on the top surface of the top liner 122, so that the gas distribution entering the process area S from the air inlet (not shown in the figure) can be more uniform. The radio frequency power source 170 is electrically connected to the supporting component 140 via the matcher 160 to provide a radio frequency voltage to the supporting component 140.

It can be seen that, by providing a magnetic component corresponding to the wafer edge region in this embodiment, the etching rate of the wafer edge can be effectively reduced, and the difference between the etching rate of the wafer center region can be reduced, thereby improving the etching uniformity of the wafer and solving the edge The electric field effect problem, and does not cause the etching by-products to be deposited inside the focus ring, which can ensure that the process is stable for a long time.

This disclosure discloses a process chamber of another embodiment. In the following description, for the purpose of brief description, any technical feature descriptions in the above embodiments that can be used for the same application are incorporated herein, and it is not necessary to repeat the same descriptions. As shown in FIG. 4, the inner layer magnet 131 and the outer layer magnet 132 are concentric ring magnets, and the polarity of the inner layer ring is opposite to that of the outer ring magnet. The S-pole of the inner ring magnet is fixed to the lower surface of the backing 121 and the N-stage faces downward toward the bottom wall 112 of the chamber body 110; The N-stage is fixed upward on the lower surface of the backing 121, or vice versa.

The magnetic component of this embodiment can also improve the etching uniformity of the wafer. Compared with the form of a plurality of cylindrical magnets, the number of parts is smaller and it is easier to process.

The above is only an exemplary description. In other examples, the inner layer magnet 131 and the outer layer magnet 132 may not be complete ring magnets, but a ring structure as a whole formed by a plurality of arc-shaped magnets arranged at equal intervals. There is no limit to the number of arc-shaped magnets, which can also improve wafer etching uniformity.

Another embodiment of the present disclosure provides a plasma device including the process chamber of the above embodiment. The plasma device is a capacitively coupled plasma device, and further, it is a capacitively coupled plasma pre-cleaning device. At the same time, the plasma device may be an inductively coupled plasma device.

The specific embodiments described above further describe the objectives, technical solutions, and beneficial effects of this disclosure in detail. It should be understood that the above are only specific embodiments of this disclosure, and are not intended to limit this disclosure. Any modification, equivalent replacement, or improvement made within the spirit and principle of this disclosure should be included in the protection scope of this disclosure.

It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "rear", "left", "right", etc., are only directions referring to the drawings, and are not Used to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of this disclosure.

Unless known to the contrary, the numerical parameters in the specification and the scope of the attached patent application are approximate values and can be changed according to the required characteristics obtained through the contents of this disclosure. Specifically, all numbers used in the specification and the scope of patent applications to indicate the content of the composition, reaction conditions, etc. should be understood to be modified in all cases by the term "about". In general, the meaning of the expression is to include a specific amount of ± 10% change in some embodiments, ± 5% change in some embodiments, ± 1% change in some embodiments, and in some implementations. ± 0.5% change in the case.

Furthermore, the word "comprising" does not exclude the presence of elements or steps that are not listed in the scope of the patent application. The word "a" or "an" preceding an element does not exclude the presence of plural such elements.

Ordinal numbers such as "first", "second", "third" and the like used in the description and the scope of patent applications to modify the corresponding element, do not themselves imply and represent that the element has any ordinal number, It does not represent the order of an element from another element, or the order of manufacturing methods. The use of these ordinal numbers is only used to make a component with a certain name clearly distinguishable from another with the same name. .

Similarly, it should be understood that, in order to streamline this disclosure and help understand one or more of the various aspects of disclosure, in the above description of the exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together into a single embodiment, Figure, or description of it. However, the method of disclosure should not be construed as reflecting the intention that the claimed present disclosure requires more features than those explicitly recorded in the scope of each patent application. Rather, as reflected in the scope of the following patent applications, the disclosure aspect is less than all the features of the single embodiment previously disclosed. Therefore, the scope of patent application following the specific embodiment is thus explicitly incorporated into the specific embodiment, wherein each patent scope of application itself serves as a separate embodiment of this disclosure.

100‧‧‧ process chamber

110‧‧‧ chamber body

111‧‧‧ sidewall

112‧‧‧ bottom wall

112a‧‧‧Exhaust port

120‧‧‧lining

121‧‧‧ underlay

122‧‧‧ Top liner

130‧‧‧Magnetic components

131‧‧‧Inner magnet

132‧‧‧ Outer magnet

140‧‧‧ support assembly

141‧‧‧base

141a‧‧‧Support plate

141b‧‧‧Insulated disk

142‧‧‧Focus ring

143‧‧‧ Bellows

150‧‧‧Homogeneous gas plate

160‧‧‧ Matcher

170‧‧‧RF Power

a‧‧‧distance

h‧‧‧Radial distance

S‧‧‧Processing area

W‧‧‧ diameter

The above and other objects, features, and advantages of the present disclosure will be clearer through the following description of the embodiments of the present disclosure with reference to the accompanying drawings. In the drawings: FIG. 1 is a schematic structural diagram of a process chamber of the present disclosure; FIG. 2 is a bottom view of a magnetic component of a process chamber according to an embodiment of the present disclosure; FIG. 3 is a magnetic field distribution diagram of a process chamber of an embodiment of the present disclosure; FIG. 4 is a magnetic module of a process chamber according to another embodiment of the present disclosure; Bottom view.

Claims (12)

A process chamber is characterized in that it comprises: a chamber body; a lining disposed in the chamber body, the lining defining a process area for forming a wafer; and a magnetic component disposed in the process area In addition, the magnetic field generated by the magnetic component can reduce the difference in the etching rate between the edge region and the central region of the wafer during the wafer processing process; and a support assembly including a base and a focus ring. A focusing ring is coupled to the base and surrounds the outer peripheral wall of the base. The base includes a support plate and an insulating plate, the support plate is used to carry the wafer, and the insulating plate is used to connect the support plate to the inner plate. Lining insulation, wherein the lining includes a top lining and a bottom lining, the top lining and the bottom lining together defining the process area, and the support assembly is disposed on the surface of the lining facing away from the bottom wall of the chamber body , The magnetic component is disposed on a surface of the backing facing the bottom wall of the chamber body, and the magnetic component corresponds to an edge region of the support component, so that the magnetic field is distributed on the edge portion of the base to The focus ring region is located. The process chamber according to item 1 of the patent application scope, wherein the magnetic component corresponds to an edge region of the wafer, so that the magnetic field generated by the magnetic component is distributed in the edge region of the wafer, so as to reduce the Etching rate of the edge area. The process chamber according to item 2 of the scope of patent application, wherein the magnetic component comprises: an inner layer magnet and an outer layer magnet distributed in a radial direction, wherein the polarity of the inner layer magnet is opposite to that of the outer layer magnet . The process chamber according to item 3 of the scope of patent application, wherein the inner layer magnet and the outer layer magnet both have a ring structure. The process chamber according to item 4 of the scope of patent application, wherein the ring structure is formed by a plurality of cylindrical magnets arranged at equal intervals. The process chamber according to item 4 of the scope of patent application, wherein the ring structure is formed by a plurality of arc-shaped magnets arranged at equal intervals. The process chamber according to item 4 of the scope of patent application, wherein the ring structure is an integrally formed ring magnet. The process chamber according to any one of claims 1 to 7 of the scope of patent application, wherein the material of the magnetic component is N38SH or N40SH. The process chamber according to any one of claims 3 to 7, wherein the diameter of the inner magnet is larger than the diameter of the wafer, and the radial distance between the inner magnet and the outer magnet is less than 30 mm. . The process chamber according to item 1 of the patent application, wherein when the magnetic component includes an inner layer magnet and an outer layer magnet, the diameter of the inner layer magnet is greater than the diameter of the wafer, and the inner layer magnet and the outer layer The radial distance between the magnets is equal to the vertical distance between the surface of the support disc facing away from the bottom wall of the chamber body and the surface of the backing facing the bottom wall of the chamber body. A capacitively-coupled plasma device is characterized in that it includes a process chamber as described in any one of the first to the tenth patent applications. The capacitively coupled plasma device according to item 11 of the scope of the patent application, wherein the capacitively coupled plasma device is a capacitively coupled plasma pre-cleaning device.