KR100387926B1 - Plasma etching apparatus - Google Patents

Abstract

The present invention is applied to plasma etching and physical or chemical vapor deposition, photo-resist stripping and other processing fields used in semiconductor wafers, flat panel displays, printed circuit boards and other thin film processing processes. The semiconductor manufacturing apparatus using the plasma, The semiconductor manufacturing apparatus using the plasma is radially installed at intervals in a constant circumferential direction on the side wall of the process chamber, each generates a plasma itself, and injects the generated plasma into the process chamber It has a plurality of high density plasma generating unit. The high-density plasma generating unit is radially spaced in two to twenty-four places at intervals in the circumferential direction of the process chamber, and is designed to achieve plasma high density, improve uniformity, and improve it.

Description

Plasma Etching Equipment {PLASMA ETCHING APPARATUS}

The present invention relates to a semiconductor manufacturing apparatus using plasma, such as a plasma etching apparatus. More specifically, plasma etching is used in semiconductors, flat panel displays, printed circuit boards and other thin film processing processes, and plasma is applied in physical or chemical vapor deposition, photo-resist stripping and other processing applications. It relates to a semiconductor manufacturing apparatus using.

Semiconductor manufacturing apparatus using plasma requires a plasma source capable of generating a uniform plasma over a wide area for manufacturing various thin films through plasma etching, physical or chemical vapor deposition, photoresist stripping and other surface treatment. do. Therefore, the manufacture of silicon and composite compound semiconductors, the manufacture of flat screens including active matrix liquid crystal screens, plasma screens, field emission screens, and the like are examples of fields requiring plasma sources.

Figure 1 shows a helicon etching device that is being used as a conventional dry etching equipment for semiconductor manufacturing. As shown in FIG. 1, the etching apparatus includes a plasma source, an antenna, a bobbin (electromagnet) for generating magnetic flux, a matching circuit, a reaction chamber including a reaction gas supply port, a reaction gas exhaust port, and the like.

The helicon etching apparatus generates plasma using Landau Damping, which is fundamentally different from the conventional RIE apparatus. As described above, the helicon etching apparatus generating plasma using landau damping may generate a high density (10 ¹² / cm 3) plasma using an RF power of 13.56 MHz.

Modes that can be used in such a helicon plasma generator may be divided into m = 0 mode and m = 1 mode according to the structure of the antenna. In the m = 0 mode, a Mori-type antenna is used, and the plasma generated by this mode has a very large difference between the center and the surroundings, which may cause uniformity problems due to the process characteristics of the center and the surroundings. This is because the density of plasma is centered by E x B motion. [See Fig. 2 (a)]

In the case of m = 1 mode, the Boswell type and Nagoya type antennas are used, and the plasma generated by this mode has a smaller difference in density from the center to the periphery than the m = 0 mode, but due to the characteristics of the antenna, Since there is a roughness of the density in the furnace, a problem may occur in the uniformity in the azimuth direction due to the process characteristics. [See FIG. 2 (b)].

In addition, in conventional etching apparatus, an exhaust port is formed at a lower position than a wafer in order to facilitate the discharge of the reaction by-product and the unreacted gas after the reaction. The exhaust port is connected to a vacuum pump (not shown) to vacuum the inside of the process chamber, and discharges unreacted process gas and by-products after the reaction, and serves to keep process conditions constant.

However, as shown in FIG. 1, since the exhaust port is present at one side with respect to the lower electrorod on which the wafer is placed, the ion density of the plasma applied to the wafer is non-uniformly formed according to the position and size of the exhaust port. Accordingly, there is a problem in that the etching proceeds unevenly with respect to one wafer. In particular, this problem becomes more serious due to the large diameter of the wafer used for the production of semiconductor devices.

The present invention has been developed to solve the above-mentioned conventional problems, and aims to improve the uniformity as well as the implementation of various densities of plasma. The present invention aims to enable uniform large area etching, deposition and surface treatment with the implementation of various densities. An object of the present invention is to form an exhaust flow in the chamber vertically downward to enable efficient exhaust.

1 is a block diagram of a conventional helicon etching device;

2 is an explanatory diagram of a conventional plasma generating antenna;

3 is a schematic structural diagram of a plasma etching apparatus according to a preferred embodiment of the present invention;

4 is a plan view of the plasma etching apparatus shown in FIG. 3;

5 is a diagram showing the arrangement of permanent magnets and the magnetic field formed by the permanent magnets;

6 is a sectional view of the plasma etching apparatus shown in FIG. 3;

FIG. 7 is a cross-sectional view taken along the line a-a shown in FIG. 6; FIG.

8 and 9 are views showing the operation of the lift device.

* Explanation of symbols for the main parts of the drawings *

110: process chamber 120: plasma generating unit

122: plasma tube 124: inductive antenna

126: permanent magnet (electromagnet) 130: gas supply pipe

140: exhaust 150: susceptor

152: cathode 154: insulator

156: electrostatic chuck 158: horizontal support

160: lift device 162: lift pins

164: "Y" shaped fork 166: the horizontal shaft

168 driving device 170 auxiliary inductive antenna

180: ion beam extractor

According to a feature of the present invention for achieving the above object, the semiconductor manufacturing apparatus using the plasma of the present invention comprises a process chamber capable of maintaining a predetermined degree of vacuum; A gas supply unit supplying a process gas into the process chamber; A plurality of high-density plasma generators disposed radially at intervals in a constant circumferential direction on the side walls of the process chamber, each generating a plasma by itself, and injecting the generated plasma into the process chamber; Holding means which is supported by a side surface of the process chamber and is placed on a workpiece to be subjected to a predetermined treatment with the plasma; And an exhaust part installed at a lower end of the process chamber so that the gas is discharged vertically downward based on the object to be placed in the holding means.

In the present invention, the holding means includes a susceptor positioned in the center of the process chamber; At least three horizontal supports mounted horizontally from the side of the process chamber and for supporting the susceptor and a wafer lift device for seating the workpiece on the susceptor. Wherein the lift device comprises at least three lift pins installed inside the susceptor and for supporting a bottom surface of the wafer; A driving device installed on one side of the process chamber and configured to vertically move the lift pins; A Y " -shaped fork having the lift pin installed at each end thereof; and a horizontal shaft connected to the port and exposed to the outside of the process chamber through an internal space of the horizontal support and connected to the drive shaft of the driving device. The susceptor may include a cathode, an electrostatic chuck on which the wafer is placed on the cathode, and an insulator disposed between the electrostatic chuck and the cathode. RF power is supplied to the cathode through the inner passages of the horizontal support, and DC power and inert cooling gas such as helium and argon may be supplied to the chuck.

In the present invention as described above, the high-density plasma generator may be installed at two to twenty four radially spaced intervals in the circumferential direction of the process chamber. The present invention is an ion beam for extracting the ion beam from the plasma and the inductive antenna formed in a spiral in the upper portion of the process chamber in order to make the density of the plasma generated from the high-density plasma generating unit supplied to the process chamber more uniform It may further include an extractor.

In the present invention, the high-density plasma generating unit and the plasma tube connected to the gas supply; An inductive antenna surrounding the outside of the plasma tube; A magnetic field generating means surrounding the antenna and the plasma tube and generating a magnetic field in the plasma. Here, the plasma tube is made of a ceramic or quartz material, the inductive antenna is formed of an antenna structure of the Mori type or M = 1 mode type of M = 0 mode, the magnetic field generating means may be a permanent magnet or an electromagnet have. Here, the inductive antenna may be water-cooled to prevent overheating generated when high frequency is applied.

In the present invention as described above, the direction of the magnetic field formed by each of the high-density plasma generating units may be opposite to the direction of the magnetic field formed by the adjacent plasma generating units, and the magnetic field generating means alternately have an N pole and an S pole. Can be arranged.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIGS. 3 to 9. In the drawings, the same reference numerals are given to components that perform the same function.

3 to 9 schematically show a high frequency inductively coupled plasma etching apparatus according to the present invention.

As shown in FIG. 3, the plasma etching apparatus 100 has a cylindrical process chamber 110 which can be maintained at a predetermined vacuum degree, and the process chamber 110 is radially spaced at a constant circumferential direction on the outer circumferential surface of the process chamber 110. An exhaust unit 140 and a turbopump 142 having six plasma generators 120 installed therein, a gas supply pipe 130 supplying process gas, an exhaust port through which treated gas and reaction by-products are exhausted, and features And holding means for holding the wafer as a lid.

7 to 9, the holding means has a susceptor 150, four horizontal supports 158, and a lift device 160.

The susceptor 150 is located at the center of the process chamber 110, and the susceptor 150 is supported by the four horizontal supports 158 which are installed horizontally from the side of the process chamber 110. do.

The lift device 160 is used to seat the wafer W on the susceptor 150. The lift device 160 includes three lift pins 162, a drive device 168, a “Y” shaped fork 164, and a horizontal shaft. It consists of 166.

The lift pin 162 is installed inside the susceptor 150 to support the bottom surface of the wafer. Each of the lift pins 162 is installed at an end of the “Y” shaped fork 164. The driving device 168 is installed on one side of the process chamber 110. The horizontal shaft 166 is connected to the fork 164 and exposed to the outside of the process chamber through the inner passage 158 of the horizontal support 158 is connected to the drive shaft 168a of the drive device 168. . As such, in the lift device 160 having one assembly, the lift pin 162 installed on the “Y” -shaped fork 164 may be moved up and down by the vertical drive of the driving device 168. 8 and FIG. 9)

The susceptor 150 includes the cathode (cathode) 152, an electrostatic chuck 156, and an insulator 154 disposed between the electrostatic chuck 156 and the cathode 152. Each of the four horizontal supports 158 has an inner passage 158a connecting the outside of the chamber and the susceptor 150. Through the inner passages 158a of the horizontal support 158, an RF power line 152a is provided to the cathode 152, and a DC power line 156a and helium gas (electrostatic power) to the electrostatic chuck 156. The cooling gas) supply line 156b used in the chuck passes.

As described above, in the plasma etching apparatus 100 according to the present invention, the susceptor 150 is not installed from the bottom of the process chamber 110, but is centered on the process chamber 110 by four horizontal supports 158. It is characterized by being installed in a supported state. Since the susceptor 150 is installed in a state of being supported from the bottom of the process chamber 110, the exhaust unit 140 may be configured below the susceptor 150 vertically (corresponding to the lower end of the process chamber). . That is, since unreacted process gas and by-products after the reaction are discharged vertically (based on the wafer placed on the susceptor) in the process chamber 110, efficient and uniform exhaust is possible.

For example, a high frequency power supply is connected to the cathode 152 through a capacitor (not shown). For example, a voltage ranging from low frequency to high frequency in the range of 100 Hz to 60 MHz may be applied to the cathode 152. . Reference numeral 180 denotes an ion beam extractor for extracting an ion beam from the plasma under the process chamber.

The process chamber 110 is performed at a process temperature of -30 to 600 degrees and a process pressure of 0.1 mT to 300 mT when etching a thin film. In particular, the process chamber 110 is 0.5 at a process temperature of 150 to 500 degrees when etching a nonvolatile thin film. It is carried out at a low pressure of mT-30mT.

The plasma generator 120, which is a characteristic component of the present invention, can generate a small-scale high-density helicon plasma. For example, a plasma generator 120 may use a conventional plasma generator having an axial magnetic field, such as a small helicon plasma source. have.

Looking at the configuration of the plasma generating unit 120 with reference to Figures 3, 4 and 6 in detail, the plasma tube 122 is supplied with a process gas for generating a plasma through the gas supply pipe 130, An inductive antenna 124 surrounding the outside of the plasma tube 122 and the magnetic field generating means surrounding the antenna 124 and the plasma tube 122 to generate a magnetic field in the plasma.

The process gas supplied through the gas supply pipe 130 may be used in combination with a conventional semiconductor process gas. For example, a photoresist mask may be used in combination with other gases based on Ar and C12 gases. The hard mask may be Ar, C12, CF4, HBr or a gas such as Ar, C12, BC13 or Ar, C12, BC13. At this time, the amount of gas used is about 0sccm-300sccm.

For example, a high frequency power supply is connected to the inductive antenna 124 through a matching circuit, and a high frequency in the range of 1 MHz to 500 MHz may be applied to the inductive antenna 124 to form a high density plasma. . Here, the plasma tube 122 is made of a ceramic material (of course, a quartz material may be used.) The gas supply pipe 130 is connected to the plasma tube 122 to supply a gas for generating plasma. The inductive antenna 124 is a Mori-type antenna structure of m = 0 mode, the inductive antenna 124 is preferably made of water-cooled to prevent overheating generated when applying a high frequency. The magnetic field generating means is composed of a permanent magnet (or electromagnet) 126.

The plasma generated by the plasma generator 120 is supplied to the process chamber 110 by the injection pressure of the process gas and the magnetic pressure by the magnetic field distribution. The plurality of plasma generators 120 used in the plasma generator 120 include a magnetic field in the axial direction.

Meanwhile, according to the embodiment of the present invention, the helicon wave plasma generated by the plasma generating unit 120 collides with the inner wall surface 114 of the process chamber during diffusion, thereby preventing the plasma from being lost in the vicinity of the wall surface. In order to increase the density, the permanent magnets 126 are alternately arranged with the north pole and the south pole as shown in FIG. By staggering in this way, it is possible to form a magnetic field distribution as shown in FIG. The arrow shown in FIG. 5 indicates the direction of the magnetic field formed by the permanent magnets 126 arranged in this manner.

Plasma generated from the six plasma generators 120 is injected into the process chamber 110, and the large-scale plasma formed as described above is processed by the magnetic field formed by the permanent magnets 126. It does not react with the inner wall 114 of) and is trapped in the barrier of the magnetic field. That is, it is possible to ensure the safety and uniformity of the large-scale plasma generated from each of the plurality of plasma generators 120 and collected in the process chamber 110, and accelerates all generated plasmas toward the chuck 150. Thus, the wafer W as a sample can be effectively processed, and further, contaminants caused by plasma can be effectively prevented from remaining inside the process chamber 110.

As described above, the plasma etching apparatus 100 of the present invention has a plurality of helicon plasma generating units 120 including an axial magnetic field capable of obtaining high plasma generating efficiency and high plasma density. The helicon plasma generating unit 120 installs the inductive antenna 124 under an axial magnetic field formed by an external permanent magnet 126 to convert the process gas introduced into the plasma tube 122 into plasma.

For example, in the plasma etching apparatus 100 of the present invention, six plasma generators 110 are installed as shown, but two, eight, twelve, depending on the size of the process chamber 110 or the wafer, Of course, the number can be increased to 16, 24, and the like. In addition, in this specification, since the size of the plasma supplied by each plasma generating unit 110 is relatively small compared to the size of the plasma generated in the process chamber 110, only the expression of large scale or small scale is used. It should be noted that such expressions as large or small are relative and are not absolutely distinguished by particular figures.

On the other hand, the plasma etching apparatus 100 according to the present invention, the density distribution of the plasma generated from the plurality of plasma generating unit 120 as described above and supplied to the process chamber 110 is irrespective of the position inside the process chamber. In order to make it uniform, the auxiliary inductive antenna 170 formed in a spiral shape may be additionally installed on the plasma generator 120. In the conventional inductive coupling plasma generation source, the number of turns of the inductive antenna has to be increased in order to apply high energy. However, according to the present invention, the number of turns of the auxiliary inductive antenna 170 need not be large. This is because the function of the auxiliary inductive antenna 170 is to supply auxiliary energy to increase the uniformity of the generated plasma unlike the conventional case. Therefore, as the number of the plasma generators 120 increases, the function of the auxiliary inductive antenna 170 may be unnecessary, and in the case of using a smaller number of plasma generators 120, the auxiliary inductive By increasing the number of turns of the antenna 170, it is possible to achieve a uniform density distribution. The auxiliary inductive antenna may use a TCP or ICP antenna.

For example, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description.

In the above, the configuration and operation of the wafer etching apparatus using the plasma according to the present invention are shown in accordance with the above description and drawings, but these are just described, for example, and various changes and modifications without departing from the technical spirit of the present invention. Of course this is possible.

The basic effect obtained by the present invention is to generate a large-scale uniform plasma inside the chamber by a plurality of plasma generating units radially installed on the side wall of the process chamber, the barrier of the magnetic field by a plurality of permanent magnets The plasma can be maintained stably by.

Therefore, a uniform high-density plasma is produced without degrading the plasma density at the center of the process chamber, and even in the case of processing a large-diameter target object (wafer or flat panel display), the helicon wave plasma can be uniformly processed. The object to be processed can be uniformly plasma treated without attenuating the density of the film.

As a result, it is possible not only to improve the reliability of the product, but also to improve the yield of the primary product, as well as to reduce the claims due to the reduction of progression defects occurring in the field, and to save time and labor costs due to the reduction of the claims. In terms of process, since a very uniform or extremely uniform plasma treatment is performed, ultimately, the improvement of the characteristics of the device and the increase in reliability are shown as the effects of the present invention.

In addition, according to the present invention, the discharge of unreacted process gas and by-products after the reaction is made vertically down the process chamber, thereby improving the plasma density uniformity on the wafer without biasing to one side.

Claims (15)

A process chamber capable of maintaining a predetermined vacuum degree; A gas supply unit supplying a process gas into the process chamber; A plurality of high-density plasma generators disposed radially at intervals in a constant circumferential direction on the side walls of the process chamber, each generating a plasma by itself, and injecting the generated plasma into the process chamber; Holding means which is supported by a side surface of the process chamber and is placed on a workpiece to be subjected to a predetermined treatment with the plasma; And an exhaust unit provided at a lower end of the process chamber so that the gas is discharged vertically downward based on the object to be placed in the holding means. The method of claim 1, The holding means A susceptor positioned in the center of the process chamber; And at least three horizontal supports mounted horizontally from a side of said process chamber and for supporting said susceptor. The method of claim 1, The holding means further comprises a wafer lift device used to seat the workpiece on the susceptor; The lift device includes at least three lift pins installed inside the susceptor and for supporting a bottom surface of the wafer; A driving device installed on one side of the process chamber and configured to vertically move the lift pins; Y " -shaped forks in which the lift pins are installed at each end thereof; And a horizontal shaft connected to the port and exposed to the outside of the process chamber through an inner space of the horizontal support and connected to a driving shaft of the driving device. The method of claim 1, The susceptor is A cathode; An electrostatic chuck on which the wafer installed on the cathode is placed; The semiconductor manufacturing apparatus using the plasma which consists of an insulator provided between the said electrostatic chuck and a cathode. The method of claim 3, wherein The horizontal support has an internal passageway, An apparatus for manufacturing a semiconductor using plasma through which RF power is supplied to the cathode and DC power and inert cooling gas are supplied to the chuck through the inner passages of the respective horizontal supports. The method of claim 1, The high-density plasma generating unit is a semiconductor manufacturing apparatus using a plasma which is provided at 2 to 24 radially at intervals in the circumferential direction of the process chamber. The method of claim 1, And an inductive antenna formed in a spiral shape on the upper portion of the process chamber to make the density of the plasma generated from the high density plasma generator and supplied to the process chamber more uniform. The method of claim 1, And an ion beam extractor for extracting an ion beam from the plasma in the lower portion of the process chamber. The method of claim 1, The high density plasma generating unit A plasma tube connected to the gas supply; An inductive antenna surrounding the outside of the plasma tube; And a magnetic field generating means surrounding the antenna and the plasma tube and generating a magnetic field in the plasma. The method of claim 8, The plasma tube is made of a ceramic or quartz material, The inductive antenna is made of an antenna structure of Mmori mode or M = 1 mode type of M = 0 mode, The magnetic field generating means is a semiconductor manufacturing apparatus using a plasma which is a permanent magnet or an electromagnet. The method of claim 8, The inductive antenna is a semiconductor manufacturing apparatus using a plasma made of water-cooled or air-cooled to prevent overheating generated when applying a high frequency. The method of claim 8, And a direction of the magnetic field formed by each of the high density plasma generators is opposite to the direction of the magnetic field formed by the adjacent plasma generators. The method of claim 8, The magnetic field generating device is a semiconductor manufacturing apparatus using a plasma in which the N pole and the S pole are alternately arranged. The method of claim 1, When the thin film is etched, the process temperature is -30 ° C to 600 ° C, and the process pressure is 0.1mT to 300mT. In particular, when the nonvolatile thin film is etched, the process temperature is 150 ° C to 500 ° C and the process pressure is low. Within the range of 0.5mT-30mT, The process frequency supplied to the inductive antenna is in the range of 1MHz-500MHz, the process frequency supplied to the cathode is in the range of 100KHz-60MH, and the power of the process frequency supplied to the inductive antenna is in the range of 0W-5000W and is supplied to the cathode. A semiconductor manufacturing apparatus using plasma having a process frequency power ranging from 0W to 5000W. The method of claim 1, The process gas is a gas used in a semiconductor process, the semiconductor manufacturing apparatus using a plasma of each of the amount of gas used is 0sccm-300sccm.