CN110610840B

CN110610840B - Bearing table and plasma equipment

Info

Publication number: CN110610840B
Application number: CN201810613391.2A
Authority: CN
Inventors: 王文章; 陈鹏; 刘菲菲
Original assignee: Beijing Naura Microelectronics Equipment Co Ltd
Current assignee: Beijing Naura Microelectronics Equipment Co Ltd
Priority date: 2018-06-14
Filing date: 2018-06-14
Publication date: 2022-05-27
Anticipated expiration: 2038-06-14
Also published as: CN110610840A

Abstract

The invention provides a bearing table and plasma equipment. The plummer includes the plummer body and runs through along the thickness direction a plurality of pinholes of plummer body, the plummer still includes at least one magnet, the magnet embedding is in the plummer body. Is beneficial to inhibiting the excitation of plasma in the pinhole and improving the process quality.

Description

Bearing table and plasma equipment

Technical Field

The invention relates to the technical field of plasma equipment, in particular to a bearing table and plasma equipment.

Background

When processing a semiconductor wafer, a stage including a carrier stage or an electrostatic chuck is generally required to carry the wafer, and these stages are generally provided with 3 pin holes, in which support pins are provided. When the supporting pins move upwards relative to the bearing table, the supporting pins can jack the wafer to a certain height; when the supporting pins move downwards relative to the bearing table, the supporting pins can drop the wafer on the bearing table.

When a wafer is processed, a strong negative bias is generally formed near the susceptor, electrons in an electric field are accelerated by the electric field in a hole under the susceptor, and when the energy of the electrons is high enough, plasma is excited. The positively charged particles in the plasma bombard the backside of the wafer, causing process instability and affecting the quality of the product.

Disclosure of Invention

The invention provides a bearing table and plasma equipment, which overcome the defects in the prior art.

According to a first aspect of the present invention, there is provided a carrier table comprising a carrier table body and a plurality of pinholes extending through the carrier table body in a thickness direction, the carrier table further comprising at least one magnet embedded in the carrier table body.

Optionally, the carrier comprises a magnet, and a line connecting a south pole and a north pole of the magnet is perpendicular to the thickness direction of the carrier body.

Optionally, the magnets are arranged in pairs, each pair of magnets corresponds to a pinhole, and the two magnets in the same pair of magnets have opposite polarities of their opposite poles.

Optionally, a line connecting the poles of the two magnets of each pair opposite to each other passes through the corresponding pin hole.

Optionally, the magnets arranged in pairs are both cylindrical magnets.

Optionally, the axial direction of the same pair of cylindrical magnets is parallel to the depth direction of the corresponding needle hole, a connecting line of mutually opposite magnetic poles between two magnets of the same pair of cylindrical magnets is perpendicular to the depth direction of the corresponding needle hole, and the connecting line passes through the corresponding needle hole; or

The axial direction of the same pair of columnar magnets is vertical to the depth direction of the corresponding needle hole, and a connecting line of mutually opposite magnetic poles between the two magnets of the same pair of columnar magnets is vertical to the depth direction of the corresponding needle hole and penetrates through the corresponding needle hole.

Optionally, the magnet includes a magnetic body and a shell for wrapping the magnetic body, and the shell is made of a conductive material.

Optionally, the thickness of the housing is between 0.8mm and 1.2 mm.

Optionally, the plummer body comprises a base portion, a bearing portion and a ring pressing portion, the bearing portion is arranged above the base portion, and the ring pressing portion is arranged above an edge portion of the bearing portion to fixedly connect the bearing portion with the base portion; the pinhole penetrates the base portion and the bearing portion, and the magnet is embedded in the base portion.

According to a second aspect of the present invention, a plasma apparatus is provided, which includes a process chamber, a susceptor, a support pin, and a feeding electrode, wherein the susceptor is disposed in the process chamber, the feeding electrode is electrically connected to the susceptor, the susceptor is the susceptor provided in the first aspect of the present invention, and the support pin can move relative to the susceptor in the pin hole.

The beneficial effects of the invention include:

because the magnetic field generated in the pinhole by the magnet embedded in the bearing table is not completely parallel to the electric field in the pinhole, namely, the electrons accelerated in the pinhole are subjected to the action of Lorentz force of a magnetic field component vertical to the moving direction of the electrons to do rotary motion, the electric field accelerates the electrons in a part of time of one period, and the electric field decelerates the electrons in another part of time of the period. The electrons are not continuously accelerated by the electric field as in the prior art, so that the increase of the energy of the electrons is suppressed, which is advantageous for reducing the probability of plasma excitation. Therefore, the wafer can be protected from being bombarded by charged particles in the plasma, and the consistency and the stability of the process are improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a cross-sectional view of a susceptor and a plasma apparatus incorporating the same according to an embodiment of the present invention;

FIG. 2 is an enlarged schematic view of a portion of FIG. 1 enclosed by dashed lines;

FIG. 3 is a schematic view showing the positional relationship of the magnetic poles of the magnet in the embodiment of the present invention;

fig. 4 is a schematic diagram showing the positional relationship of the magnetic poles of the magnet in another embodiment of the present invention.

Detailed Description

The following describes in detail embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

According to a first aspect of the present invention, there is provided a carrier table, as shown in fig. 1, comprising a carrier table body and a plurality of pin holes 11 penetrating through the carrier table body in a thickness direction, the carrier table further comprising at least one magnet 20, the magnet 20 being embedded in the carrier table body.

Fig. 2 shows a cross-sectional view of the carrier, in which only one pinhole 11 is shown, the remaining pinholes 11 being outside the cross-section of the cross-sectional view and therefore not shown in fig. 2.

When the susceptor is used in a plasma apparatus, the bottom of the susceptor is grounded, and the susceptor is electrically connected to the feeding electrode 15. In addition, a support pin 30 for lifting up the wafer 40 is provided in the pin hole 11 of the stage.

During operation of the plasma apparatus, the feedthrough electrode 15 introduces a negative bias near the carrying surface of the stage, while the bottom of the stage is grounded, thereby forming an electric field from the bottom of the stage to the carrying surface (the solid arrows in fig. 2 indicate the direction of the electric field). Since the magnetic field generated by the magnet 20 (the direction of the magnetic field strength of the magnetic field is indicated by the dotted arrow in fig. 2) is not completely parallel to the electric field in the pinhole 11, electrons are subjected to lorentz force in the magnetic field to perform a cyclotron motion, the electric field performs an acceleration motion on the electrons during a part of a motion cycle, and the electric field performs a deceleration motion on the electrons during another part of the motion cycle. The electrons are not continuously accelerated by the electric field as in the prior art, and thus the energy of the electrons is suppressed. In this way, the probability of plasma excitation is advantageously reduced. Thereby protecting the wafer 40 from being bombarded by charged particles in the plasma and improving the consistency and stability of the process.

Optionally, a magnet 20 is embedded in the carrier body, so that most of the components of the magnetic field generated by the magnet are perpendicular to the direction of the electric field in each pinhole 11, and the line between the south pole S and the north pole N of the magnet is perpendicular to the thickness direction of the carrier body.

Even if only one magnet 20 is provided in the stage body, the magnetic field of the magnet 20 is applied to the plurality of pin holes 11 in the stage body, and the acceleration of electrons in the pin holes 11 is suppressed.

Alternatively, as shown in fig. 3 and 4, the magnets 20 are arranged in pairs, each pair of magnets 20 corresponds to one pinhole 11, and the two magnets 20 in the same pair of magnets 20 have opposite polarities of their opposite poles.

That is, a pair of magnets 20 is disposed near each pinhole 11, thus enhancing the magnetic field in each pinhole 11.

The two magnets 20 of the same pair of magnets 20 have opposite poles with respect to each other, i.e., one magnet has opposite poles with respect to the other magnet. For example, the south pole S of one magnet 20 is opposite the north pole N of another magnet 20 in fig. 4. For another example, in fig. 3, the south pole S at one end of the columnar magnet 20 is opposite to the north pole N at one end of the other columnar magnet 20, and the north pole N at the other end of the former is opposite to the south pole S at the other end of the latter (not shown since it is not in the section plane). This is provided to further enhance the magnetic field within the pinhole 11.

Alternatively, the line connecting the poles of the two magnets of each pair of magnets 20 opposite to each other passes through the corresponding needle hole 11. That is, the strongest part of the magnetic field generated by the pair of magnets 20 is located in the pinhole 11, thereby increasing suppression of electron acceleration by the magnetic field.

Note that the dashed lines in fig. 4 indicate lines of magnetic force. The views in fig. 3 and 4 are cross-sectional views perpendicular to the pinhole 11.

It should be noted that the present invention does not require any particular shape of the magnet 20, and for example, in fig. 4, the magnet 20 is cylindrical, and the south pole S is provided at one end of the cylindrical magnet 20 in the height direction and the north pole N is provided at the other end. The magnet 20 is again, for example, horseshoe-shaped, etc.

As a preferred embodiment, as shown in fig. 3, the axial direction of the same pair of cylindrical magnets 20 is parallel to the depth direction of the corresponding pinhole 11, the line of the mutually opposite magnetic poles between the two magnets 20 of the same pair of cylindrical magnets 20 is perpendicular to the depth direction of the corresponding pinhole 11 and the line passes through the pinhole 11; or as shown in fig. 4, the axial direction of the same pair of cylindrical magnets 20 is perpendicular to the depth direction of the corresponding needle hole 11, and the line of the mutually opposite magnetic poles between the two magnets 20 of the same pair of cylindrical magnets 20 is perpendicular to the depth direction of the corresponding needle hole 11 and passes through the needle hole 11.

Alternatively, as shown in fig. 3 and 4, the plurality of pinholes 11 are uniformly distributed on the same circumference. In the example of fig. 3 and 4, the plane of the circumference is perpendicular to the depth direction of the pinhole 11 corresponding to the circumference.

Optionally, the magnet 20 includes a magnetic body and a shell for wrapping the magnetic body, and the material of the shell is a conductive material.

As described above, the housing is made of a conductive material, and thus can shield an electric field. In the present invention, the housing prevents a high-frequency electric field outside the magnet 11 from affecting the magnetic field of the magnet 11.

Optionally, the thickness of the housing is between 0.8mm and 1.2 mm. Preferably, the housing thickness is 1 mm.

This is because the thickness of the housing must not be too thin, at least greater than the skin depth of the conductive material of the housing itself.

Alternatively, as shown in fig. 2, the plummer body comprises a base part 13, a bearing part 14 and a pressing ring part 17, wherein the bearing part 14 is arranged above the base part 13, and the pressing ring part 17 is arranged above the edge part of the bearing part 14 to fixedly connect the bearing part 14 with the base part 13; the needle hole 11 penetrates the base portion 13 and the bearing portion 14, and the magnet 20 is embedded in the base portion 13.

Specifically, the bearing part 14 includes a boss and a flange disposed around the boss, a top surface of the boss is formed as a bearing surface, and the pressing ring part 17 is disposed around the boss and located above the flange to fixedly connect the bearing part 14 with the base part 13.

Specifically, the base portion 13 is formed with a feeding electrode hole (a hole in which the feeding electrode 15 is located) penetrating the base portion 13 in the thickness direction.

As shown in fig. 2, the carrier 14 carries the wafer 40, and the carrier 14 is, for example, an electrostatic chuck or a carrier stage. The carrier part 14 is generally made of a material having high electrical conductivity, such as Al or Ti.

The material of the base portion 13 is, for example, ceramic or quartz. A lower lining 63 is arranged on the side of the base part 13 remote from the carrier part 14 (as shown in fig. 1). The lower liner 63 is grounded.

The magnet 20 is embedded in the base part 13, and may be realized, for example, by a method of mixing the magnet 20 into powder to be sintered before ceramic sintering of the base part 13.

It should be noted that the magnetic field in the pinhole 11 is sufficiently large. Optionally, the magnetic induction generated by the magnet 20 in the pinhole 11 is between 10 gauss and 100 gauss. Within this range of values, the cyclotron radius of the electrons in the magnetic field in the pinhole 11 is smaller than the mean free path of the electrons.

When the bearing table works, the bearing table is arranged in a process cavity of plasma equipment, and when a plasma process (including processes such as pre-cleaning and etching) is carried out in the process cavity, the process cavity needs to be vacuumized. Preferably, the magnet 20 is formed of a non-volatile material, and when the magnet made of the non-volatile material is applied to a vacuum chamber, volatile gas is not generated, thereby not affecting a process, nor damaging a vacuum system forming a vacuum environment.

According to a second aspect of the present invention, as shown in fig. 1, there is provided a plasma apparatus, which includes a process chamber 60, a susceptor 60 disposed in the process chamber 60, a supporting pin 30 and a feeding electrode 15, wherein the feeding electrode 15 is electrically connected to the susceptor, and the susceptor is the susceptor provided according to the first aspect of the present invention, and the supporting pin 30 can move relatively to the susceptor in the pin hole 11.

Specifically, the plummer is fixedly arranged, and the supporting needle 30 moves up and down under the drive of a motion mechanism (not shown in fig. 2); or the supporting needle 30 is fixedly arranged, and the plummer moves up and down under the driving of the motion mechanism; or both can move up and down.

The supporting pins 30 protrude from the outlets of the pin holes 11 to lift the wafer 40. The support pins 30 enter the pin holes 11 from the outside of the exit of the pin holes 11 in order to mount the wafer 40 on the carrying surface of the stage.

Optionally, as shown in fig. 2, the plasma apparatus further includes a focus ring 16, and the focus ring 16 is disposed around the carrying surface of the carrying stage.

Optionally, as shown in fig. 2, the bearing table body includes a base portion 13, a bearing portion 14, and a pressure ring portion 17, the bearing surface is formed on the bearing portion 13, the pressure ring portion 17 is disposed on the periphery of the bearing surface of the bearing portion 13 and on the same side of the bearing portion 13 as the bearing surface, the base portion 13 is disposed on the opposite side of the bearing portion 14 from the bearing surface; the pinhole 11 penetrates through the base part 13 and the bearing part 14, the magnet 20 is embedded in the base part 13, and the base part 13 is provided with a feed electrode hole penetrating through the base part 13 along the thickness direction; the plasma equipment also comprises a feed electrode 15, and one end of the feed electrode 15 penetrates through the feed electrode hole to be electrically connected with the bearing part 14.

The plasma apparatus further comprises a plasma generating device (not shown in fig. 1) for igniting a plasma.

Specifically, the rf power supply 66 conducts rf power to the feeding electrode 15 through the rf matcher 65.

Other components of the plasma apparatus that cooperate with the susceptor are also shown in fig. 2: bellows 12, feedelectrode 15 and focus ring 16. The bellows 12 is often constructed of a material having a relatively high dielectric constant, such as quartz, ceramic, or the like.

Optionally, as shown in fig. 1, the process chamber 60 includes a chamber wall defining the process chamber, an upper liner 61, an air distribution plate 62, and a lower liner 63, the upper liner 61 and the lower liner 63 are both disposed within the process chamber, the air distribution plate 62 is disposed on a top wall of the chamber wall, and the upper liner 61 is disposed around the air distribution plate 62; the lower liner 63 comprises a liner bottom wall and a liner side wall surrounding the liner bottom wall, the lower end of the upper liner 61 is located on the inner side of the liner side wall, the bearing table is arranged on the liner bottom wall, and the lower liner 63 can reciprocate along the height direction of the process chamber to form an opening between the liner side walls of the upper liner 61 and the lower liner 63.

In this example, when an opening is formed between the sidewalls of the upper liner 61 and the lower liner 63, the wafer 40 may enter the opening through the wafer transfer port 64 to reach the load bearing surface. Or vice versa. The lower liner 63 moves up and down in synchronization with the carrier table.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.

Claims

1. The utility model provides a plummer, the plummer includes the plummer body and runs through along the thickness direction a plurality of pinholes of plummer body, its characterized in that, the plummer still includes at least one magnet, the magnet embedding is in the plummer body, just the magnet is in downthehole produced magnetic field of pinhole with the downthehole electric field of pinhole can not be completely parallel.

2. The carrier table of claim 1, wherein the carrier table comprises a magnet, and the line of south pole and north pole of the magnet is perpendicular to the thickness direction of the carrier table body.

3. The carrier table of claim 1, wherein the magnets are arranged in pairs, each pair of magnets corresponding to a pinhole, and two magnets in the same pair of magnets having opposite polarities of their opposite poles.

4. A carrier table according to claim 3, wherein the two magnets of each pair are connected by a line of mutually opposite poles passing through the respective pin hole.

5. The susceptor of claim 3, wherein the magnets arranged in pairs are cylindrical magnets.

6. The loading platform of claim 5, wherein the axial direction of the same pair of cylindrical magnets is parallel to the depth direction of the corresponding pin hole, and a connecting line of the magnetic poles opposite to each other between the two magnets of the same pair of cylindrical magnets is perpendicular to the depth direction of the corresponding pin hole and penetrates through the corresponding pin hole; or

7. The carrying table according to claim 1, wherein the magnet comprises a magnetic body and a shell for wrapping the magnetic body, and the shell is made of a conductive material.

8. The carrier table of claim 7, wherein the housing has a thickness of between 0.8mm and 1.2 mm.

9. The susceptor of any one of claims 1 to 8, wherein the susceptor body comprises a base portion, a bearing portion and a pressure ring portion,

the bearing part is arranged above the base part, and the pressing ring part is arranged above the edge part of the bearing part so as to fixedly connect the bearing part with the base part;

the pinhole penetrates the base portion and the bearing portion, and the magnet is embedded in the base portion.

10. Plasma equipment, the plasma equipment includes process chamber, plummer, support needle and feed electrode, the plummer sets up in the process chamber, the feed electrode with the plummer electricity is connected, characterized in that, the plummer is according to any one of claim 1-9 the plummer, the support needle can with the plummer relative motion in the pinhole.