KR102582699B1 - Plasma etching apparatus - Google Patents

Abstract

The etching apparatus of the present invention includes a first chamber forming part and a second chamber forming part defining a predetermined space between the first chamber forming part, and opposing each other with a workpiece in between within the space. An anode and a cathode are disposed, and a gas supply mechanism for injecting at least a type of etching gas into the space, wherein the gas supply mechanism is configured to surround the workpiece within the space. It includes a gas transfer pipe that guides the etching gas, and a plurality of nozzles disposed in the gas transfer pipe to discharge the etching gas into the space.

Description

Plasma etching device {PLASMA ETCHING APPARATUS}

The present invention relates to a plasma etching device, and more specifically, to an etching device that improves etching uniformity by evenly supplying etching gas into a chamber where etching takes place.

Plasma etching involves injecting gas into a vacuum chamber maintained at a pressure lower than normal atmospheric pressure, supplying electrical energy to generate plasma, and then colliding it with the surface of the material to etch the desired pattern. This technology is widely used in thin film processing and semiconductor fields.

Accurate etching is essential to obtain high yield, and etching quality is determined by several factors such as uniformity and etch rate. In particular, uniformity refers to how evenly the etching progressed. High uniformity can be secured only when the entire area of the machined surface is etched evenly. To achieve this, the reactive gas injected into the chamber to generate plasma must act evenly on the machined surface. It is important to be able to do so.

Korean Patent Publication No. 10-2018-0044124

The problem that the present invention aims to solve is, first, to provide an etching device that secures uniformity in etching quality and improves yield by evenly supplying etching gas into the chamber where the workpiece is etched so that plasma is evenly distributed within the chamber. It is done.

Second, to provide an etching device that can obtain uniform etching quality regardless of whether multiple workpieces are etched simultaneously or a single workpiece is etched.

Third, in the case of supplying an etching gas mixed with two or more types, an etching device is provided in which the gases are supplied into the chamber in an evenly mixed state.

Fourth, it is to provide an etching device that can vary the structure of the pipe that guides the etching gas according to the characteristics of the workpiece.

First, the etching device of the present invention has the effect of uniformly generating plasma and improving the uniformity of etching quality because the etching gas is evenly dispersed or diffused within the chamber.

Second, because the plasma is formed uniformly within the chamber, uniform etching quality can be obtained not only when etching a single workpiece, but also when etching multiple workpieces simultaneously.

Third, in the case of etching gases composed of two or more types, since the gases are mixed and then supplied into the chamber, a homogeneous plasma is generated within the chamber.

Fourth, since the branch pipe can be selectively coupled to or separated from the pipe mount formed on the circumferential pipe, the etching gas supply passage can be easily configured in an appropriate form according to the characteristics such as size, number, and arrangement of the workpiece.

Figure 1 shows a side cross-section of an etching device according to a first embodiment of the present invention.
Figure 2 is a view of the etching apparatus of Figure 1 in the Z direction.
3 and 4 show an etching device according to a second embodiment of the present invention.
Figure 5 shows an etching device according to a third embodiment of the present invention.
Figure 6 shows an etching device according to a fourth embodiment of the present invention.
Figure 7 shows an etching device according to a fifth embodiment of the present invention.
Figure 8 shows another embodiment of a gas transfer pipe.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to be understood by those skilled in the art. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Figure 1 shows a side cross-section of an etching device according to a first embodiment of the present invention. Figure 2 is a view of the etching apparatus of Figure 1 in the Z direction.

Referring to FIGS. 1 and 2, the etching device 100 according to an embodiment of the present invention etches the workpiece 2a (2a(1), 2a(2), 2a(3)). It includes a chamber 10 that defines the space in which this takes place. The chamber 10 may include a first chamber forming part 11 and a second chamber forming part 12 defining a predetermined space between the first chamber forming part 11 and the first chamber forming part 11 .

The chamber 10 may be configured to be open and closed to allow entry and exit of the workpiece 2a. The space can be opened and closed by moving one of the first chamber forming part 11 and the second chamber forming part 12 relative to the other.

The second chamber forming part 12 may be configured to be movable in a predetermined direction (hereinafter, defined as the Z direction in the drawings) with respect to the first chamber forming part 11. The space may be closed when the second chamber forming part 12 moves in one direction (+Z direction), and the space may be opened when it moves in the opposite direction (-Z direction). Although not shown, a guide part that guides the movement of the second chamber forming part 12 in the Z direction may be provided.

A vacuum pump (not shown) may be provided to depressurize the chamber 10. Since the etching process must be performed at a very low pressure, usually called weak vacuum or vacuum, a vacuum pump is provided to create a low pressure atmosphere.

In order to open the chamber 10 after the etching process is completed, a ventilation unit 13 may be provided to ventilate the space within the chamber 10 with external air. The ventilation unit 13 may include a ventilation pipe 13a that communicates the space with outside air, and a damper 13b that opens and closes the ventilation pipe 13a. A control unit (not shown) may be provided to control the opening and closing of the damper 13b. The control unit can control the operation of various electrical and electronic components constituting the damper 13b as well as the etching device 1: 1a, 1b, 1c, 1d, 1e.

Each chamber forming portion 11, 12 may form a concave space with one side open. The chamber forming parts 11 and 12 may be arranged on both left and right sides as in the embodiment so that one open surface faces a horizontal direction. However, the limitation is not limited to this, and the first chamber forming part 11 is arranged to be open upward, and the second chamber forming part 12 has one open side facing downward and is located on the upper side of the first chamber forming part 11. It may be arranged and configured to move up and down to open and close the space.

A cathode 20 and an anode 50 may be disposed in the chamber 10. The cathode 20 may be provided in the first chamber forming part 11, and the anode 50 may be provided in the second chamber forming part 12.

The etching devices 1a, 1b, 1c, 1d, and 1e may include a power supply 51 that applies high-frequency alternating current to the cathode 20. The cathode 20 and the anode 50 each have substantially flat surfaces facing each other, and at least one workpiece 2a may be disposed on the flat surface of the cathode 20.

A cathode insulator 30 may be provided to insulate the cathode 20 from the first chamber forming portion 11. The cathode insulator 30 is fixed to the inside of the first chamber forming part 11 and may form a groove in which the cathode 20 is seated. The cathode insulator 30 can be made of any material as long as it has insulating properties, but is preferably an oxide such as aluminum oxide (Al2O3) or a nitride such as aluminum nitride (AlN).

A cathode protection sheet 40 may be provided on one surface of the cathode 20 to protect the area where the workpiece 2a is not placed from being exposed to plasma. By the cathode protection sheet 40, a region on one surface of the cathode 20 where etching of the workpiece 2a is performed and a non-etching region can be distinguished.

Referring to FIG. 2, the cathode protection sheet 40 has a peripheral portion (hereinafter referred to as 'cathode electrode surface') that surrounds the edge of the cathode 20 on which the workpiece 2a is placed. 21) and at least one partition 22 that divides the inner area defined by the peripheral part 21 into a plurality of parts. In the embodiment, the partitions 22(1) and 22(2) are formed in the form of a plurality of parallel straight lines extending in one direction, but are not necessarily limited thereto. The workpieces 2a(1), 2a(2), and 2a(3) may be disposed in areas divided by at least one partition 22(1) and 22(2), respectively.

An anode protection sheet 60 may be provided on one side of the anode 50 (hereinafter referred to as 'anode electrode surface') facing the cathode 20. The anode protection sheet 60 is intended to protect a specific area of the anode electrode surface from being exposed to plasma, and the specific area may be formed in a shape corresponding to the non-etched image of the cathode electrode surface.

The anode protection sheet 60 may have a shape corresponding to the cathode protection sheet 40. In other words, the anode protection sheet 60 may include a peripheral portion 61 and at least one partition portion 62 (62(1), 62(2)).

A gas supply device 70 (hereinafter divided into 70a, 70b, 70c, 70d, and 70e depending on the embodiment) for injecting at least a kind of etching gas into the chamber 10 is provided. The etching gas becomes a plasma state in which free electrons, ions, neutral atoms, ionized gas molecules, etc. are mixed by the electromagnetic field formed between the anode 50 and the cathode 20, and the plasma thus formed is formed on the workpiece 2a. Etching occurs by impacting the surface.

Meanwhile, a photoresist film (not shown) on which a pattern is formed through exposure may be attached to one surface of the workpiece 2a where etching is performed. The portion of the workpiece 2a excluding the pattern protected by the photoresist film may be etched. This also applies to workpieces in other embodiments described later.

The gas supply mechanism 70a can supply a gas that is a mixture of two or more gases (hereinafter referred to as 'mixed etching gas').

The gas supply mechanism 70a includes a first gas supply pipe 71a for supplying a first etching gas, a second gas supply pipe 71b for supplying a second etching gas of a different type from the first etching gas, and a first etching gas. It may include a gas mixing portion 73 connected to the gas supply pipe 71a and the second gas supply pipe 71b to mix the first etching gas and the second etching gas.

The gas supply mechanism 70a may include a gas discharge unit 80a that discharges the gas mixed in the gas mixing unit 73 into the chamber 10. The gas discharge unit 80a includes a first gas distribution pipe 84a and a second gas distribution pipe 84b, which respectively guide the mixed etching gas distributed from the gas mixing unit 73, and a first gas distribution pipe 84a. It may include a first gas discharge pipe 81 and a second gas discharge pipe 82 respectively connected to the second gas distribution pipe 84b. Each gas discharge pipe 81 and 82 may be provided with a plurality of nozzles 88 that discharge mixed etching gas into the chamber 10.

In the conventional structure of supplying two types of etching gases, the first etching gas supplied through the first gas supply pipe 71a is discharged directly into the chamber 10, and the second etching gas supplied through the second gas supply pipe 71b Gas was also discharged directly into the chamber 10. That is, the two types of etching gases were finally dispersed and mixed within the chamber 10. Therefore, in order to uniformly spread or disperse gases, it was necessary to maintain a very high vacuum within the chamber 10, and for this reason, a high-performance vacuum pump was needed.

In addition, not only did it take time to uniformly mix the gases within the chamber 10, but the uniformity of the gases was not clearly guaranteed, so there was a problem of poor etching quality and yield.

On the other hand, in a structure like the embodiment, not only are different types of etching gases uniformly mixed in advance in the gas mixing unit 73, but also the chamber ( 10) Since it is supplied internally, the above-mentioned conventional problems can be solved.

Meanwhile, as in the embodiment, when the chamber 10 has a structure that defines a rectangular space standing up and down, each gas discharge pipe 81 and 82 may be configured to discharge the mixed etching gas into the lower area of the space. .

Meanwhile, the gas supply mechanism 70a may include a first control valve 72a that controls the first gas supply pipe 71a and a second control valve 72b that controls the second gas supply pipe 71b. . The first control valve 72a and the second control valve 72b may be electromagnetic valves controlled by a control unit (not shown).

3 and 4 show an etching device according to a second embodiment of the present invention. Referring to FIGS. 3 and 4, the etching device 1b according to the second embodiment of the present invention is different from the etching device 1a according to the first embodiment described above in the gas supply mechanism 70b. .

The gas supply mechanism 70b includes a first gas supply pipe 71a for supplying a first etching gas, a second gas supply pipe 71b for supplying a second etching gas of a different type from the first gas, and a first gas supply pipe 71a. A gas mixing unit 73 connected to the supply pipe 71a and the second gas supply pipe 71b to mix the first etching gas and the second etching gas, and the gas mixed in the gas mixing unit 73 is supplied to the chamber. (10) It may include a gas discharge portion (80b) that discharges into the inside.

The gas discharge unit 80b includes a first gas distribution pipe 84a and a second gas distribution pipe 84b, which respectively guide the mixed etching gas distributed from the gas mixing unit 73, and a first gas distribution pipe 84a. ) and a gas transfer pipe 800 connected to the second gas distribution pipe 84b, and a plurality of nozzles 88 disposed in the gas transfer pipe 800 to discharge the mixed etching gas into the chamber 10. there is.

The first gas distribution pipe 84a and the second gas distribution pipe 84b are connected in parallel, and the mixed etching gas output from the gas mixing unit 73 is supplied to the first gas distribution pipe 84a and the second gas, respectively. It branches off into the distribution pipe (84b).

The gas transfer pipe 800 may be formed to surround the workpiece 2b. The first gas distribution pipe 84a and the second gas distribution pipe 84b may be connected to different points on the gas transfer pipe 800.

The gas transfer pipe 800 may be annular. Here, the annulus is not limited to a circular or curved shape, but is defined as an enclosing or closed form. When viewed from the Y direction orthogonal to the Z direction, the gas transfer pipe 800 or the circumferential pipe 810 (see FIG. 5), which will be described later, may be disposed between the cathode 20 and the anode 50.

The gas transfer pipe 800 may be formed in a shape corresponding to the electrode surface of the cathode 20 or anode 50. For example, as in the embodiment, the gas transfer pipe 800 may be formed in a substantially rectangular shape.

The gas transfer pipe 800 includes a first horizontal section 811 extending in the Y direction in the It may include a section 812 and first and second vertical sections 813 and 814 that are spaced apart from each other in the Y direction and connect both ends of the first horizontal section 811 and both ends of the second horizontal section 812, respectively. there is.

The nozzles 88 formed in the gas transfer pipe 800 may have a structure in which the injection holes are opened toward the area surrounded by the gas transfer pipe 800. A plurality of nozzles 88 may be disposed on each side of the rectangular shape.

Since the mixed etching gas is sprayed through the nozzles 88 arranged to surround the workpiece 2b, a homogeneous mixed etching gas mixed at a uniform concentration is evenly supplied between the cathode 20 and the anode 50. It can be. Etching is performed evenly on the entire surface of the workpiece, resulting in uniformity.

Meanwhile, in a state where a homogeneous mixed etching gas is supplied between the cathode 20 and the anode 50, movement is caused microscopically due to the difference in density between the two types of gases, so that the gas with a large atomic weight or molecular weight is lower than the gas with a smaller atomic weight. moves to , and depending on the embodiment, this phenomenon acts as a positive factor in the etching process.

Figure 5 shows an etching device according to a third embodiment of the present invention. Referring to FIG. 5, the etching device 1c according to the third embodiment of the present invention has a different structure of the gas transfer pipe 800a compared to the above-described second embodiment.

The gas transfer pipe 800a may include an annular circumferential pipe 810 and a branch pipe 820 having both ends respectively connected to two points of the circumferential pipe 810. The circumferential pipe 810 substantially corresponds to the gas transfer pipe 800 in the above-described embodiment and includes first and second horizontal sections 811 and 812 and first and second vertical sections 813 and 814. It can be included.

A plurality of nozzles 88 may be provided along the circumferential tube 810. Each nozzle 88 may have a structure in which the injection hole is open toward the area surrounded by the circumferential tube 810. Nozzles 88 may be disposed in the first and second horizontal sections 811 and 812 and the first and second vertical sections 813 and 814, respectively.

The branch pipe 820 may connect the first vertical section 813 and the second vertical section 814 between the first horizontal section 811 and the second horizontal section 812. The area defined by the circumferential pipe 810 is divided by the branch pipe 820, and the workpieces 2a (1), 2a (2), and 2a (3) can be placed in these divided areas, respectively. . The branch pipe 820 may be disposed in an area corresponding to the cathode protection sheet 40.

The branch pipe 820 may be configured to asymmetrically divide the entire area surrounded by the circumferential pipe 810. That is, the branch pipe 820 may divide the entire area into a large area S1 with a relatively large area and a small area S2 with a relatively small area. For example, as in the embodiment, the branch pipe 820 becomes a boundary dividing the entire area into three, with one side of the boundary being 1/3 of the total area and the other side being 2/3 of the total area. It may be divided into 3.

In this way, when the area surrounded by the circumferential pipe 810 is divided asymmetrically, at least one nozzle 88a formed in the branch pipe 820 will be configured so that its spray direction is toward the large area area S1. You can. Since a larger flow rate of gas is sprayed to a large area, the gas concentration difference depending on the area can be reduced, and therefore, the workpiece (2a(1)) processed in the small area area (S2) and the large area area (S1) There is an effect of securing a uniform yield between the workpieces (2a(2) and 2a(3)) processed in .

Referring to FIG. 6, a plurality of branch pipes 820 may be arranged to cross each other horizontally and vertically. The horizontal and vertical branch pipes 820(1), 820(2), 820(3), and 820(4) intersect with each other to form a cross-shaped flow path.

The structure in which the branch pipes 820 intersect divides the area surrounded by the circumferential pipe 810 into a lattice shape, and the workpiece 2c can be placed in each of these divided areas. In the embodiment, nine workpieces 2c are each arranged in nine divided areas, but this is not necessarily limited to this.

To ensure that the gas can be sprayed evenly into each area divided into grids, nozzles 88 are arranged on the sides surrounding each divided area so that the gas can be sprayed into the corresponding area. For example, as shown in FIG. 6, nozzles are arranged on each side of a rectangular pipe surrounding each area divided in a grid shape, so that gas can be injected into the inside of the rectangle.

Nozzles with opposite spray directions may be disposed on both sides of the branch pipe 820 so that the mixed etching gas can be supplied from one branch pipe 820 to each region divided into two sides.

Figure 7 shows an etching device 1e according to a fifth embodiment of the present invention. Referring to FIG. 7, the branch pipes 820 can be combined so that the branch pipes 820 can be arbitrarily configured according to the size, number, and arrangement of the workpieces 2d(1) and 2d(2), That is, the branch pipe 820 may be configured so that the user can arbitrarily combine or separate it.

The gas transfer pipe 800c may include a plurality of pipe mounts 860 arranged along the circumferential pipe 810 and to which a branch pipe 820 is detachably coupled. The conduit mount 860 may form a conduit connecting the circumferential pipe 810 and the branch pipe 820. Depending on the size or shape of the workpiece (2d(1), 2d(2)), it is possible to configure a gas transfer path optimized for the work by combining the branch pipe 820 with the desired pipe mount 860.

In FIG. 7 , nozzles with the same injection direction are arranged along the branch pipe 820 as an example, but it is also possible to consist of nozzles that spray gas in opposite directions as shown in FIG. 6 .

Meanwhile, although not shown, a control valve that regulates the pipe mount 860 may be provided. The control valve may be a manually, mechanically or electrically operated valve. In a state where the branch pipe 820 is separated from the pipe mount 860, the pipe mount 860 may be closed by the control valve. Pipe mounts 860 may be disposed along the inner periphery of the circumferential pipe 810.

Meanwhile, the conduit mount 860 may be closed when not coupled to the branch pipe 820, and open when coupled. For example, the conduit mount 860 may be used for attachment and detachment of the branch pipe 820. It may be a check valve that is mechanically opened or closed correspondingly.

Alternatively, a valve (not shown) may be provided to control each pipe mount 860, and the valve may be manually opened and closed, or alternatively, the opening and closing may be electrically controlled by a control unit.

Meanwhile, a connection joint 850 may be further provided to connect the horizontal sections 811 and 812 and the vertical sections 813 and 814.

FIG. 8 shows one embodiment of a branch pipe assembly coupled to the pipe mount 820 shown in FIG. 7. Referring to FIG. 8, the branch pipe 820 may be composed of a plurality of pipes 880a, 880b, 880c, and 880d connected to each other by a joint 870. The pipes 880a, 880b, 880c, and 880d may be connected in all directions by a joint 870. In this case, joint 870 may be a cross fitting.

As shown in FIG. 6 , in the case of a lattice structure in which several horizontal and vertical branch pipes 820 intersect each other, joints 870 may be provided at each point where the branch pipes 820 intersect.

1a, 1b, 1c, 1d, 1e: Etching device 2a, 2b, 2c, 2d: Workpiece
10: Chamber 20: Cathode
30: cathode insulator 40: cathode protection sheet
50: anode 60: anode protection sheet
70a, 70b, 70c, 70d, 70e: gas supply mechanism 80a, 80b: gas discharge part

Claims (11)

First chamber forming part;
a second chamber forming portion defining a predetermined space between the first chamber forming portion and the first chamber forming portion;
An anode and a cathode arranged within the space to face each other with a workpiece in between; and
It includes a gas supply mechanism for injecting at least some kind of etching gas into the space,
The gas supply mechanism is,
a gas transfer pipe disposed between the anode and the cathode and configured to surround the workpiece within the space to guide the etching gas; and
It includes a plurality of nozzles disposed in the gas transfer pipe to discharge the etching gas into the space,
The gas transfer pipe is,
a first horizontal section extending in the Y direction based on XY coordinates defining a predetermined plane on which the workpiece is disposed;
a second horizontal section spaced apart from the first horizontal section in the X direction and extending in the Y direction; and
An etching device comprising first and second vertical sections spaced apart from each other in the Y direction and connecting both ends of the first horizontal section and both ends of the second horizontal section, respectively. According to claim 1,
The gas supply mechanism is,
A first gas supply pipe supplying the first gas;
a second gas supply pipe supplying a second gas of a different type from the first gas; and
A gas mixing unit connected to the first gas supply pipe and the second gas supply pipe to mix the first gas and the second gas,
The etching gas is,
An etching device formed by mixing the first gas and the second gas in the gas mixing section. According to claim 2,
The gas supply mechanism is,
The etching device further includes a first gas supply pipe and a second gas supply pipe that respectively guide the etching gas to different points on the gas transfer pipe. According to claim 2,
The etching device is,
a first control valve controlling the first gas supply pipe; and
An etching device further comprising a second control valve that controls the second gas supply pipe. delete delete According to claim 1,
The gas transfer pipe is,
The etching apparatus further includes a branch pipe connecting the first vertical section and the second vertical section between the first horizontal section and the second horizontal section. According to claim 7,
A cathode protection sheet is disposed on one side of the cathode facing the anode to separate areas where a plurality of workpieces are disposed,
The branch pipe is,
An etching device disposed in an area corresponding to the cathode protection sheet. According to claim 1,
The gas transfer pipe is,
A circumferential tube surrounding the workpiece; and
It includes a branch pipe that divides the area surrounded by the circumferential pipe into a large area area and a small area area,
In the branch pipe,
An etching device in which a plurality of nozzles are disposed to spray the etching gas into the large area. According to claim 1,
The gas transfer pipe is,
A circumferential tube surrounding the workpiece;
A plurality of pipe mounts formed on the circumferential pipe; and
An etching device comprising a branch pipe whose both ends are respectively connected to a pair of the plurality of pipe mounts. According to claim 1,
The gas transfer pipe is,
A circumferential tube surrounding the workpiece; and
It includes a branch pipe that divides the area surrounded by the circumferential pipe into a large area area and a small area area,
The branch pipe is,
An etching device in which multiple etching devices are arranged horizontally and vertically.