KR20020004623A - Etcing equipment for plasma of semiconductor - Google Patents

Abstract

PURPOSE: A semiconductor plasma etch equipment is provided to improve etch uniformity by controlling convection within a chamber. CONSTITUTION: A gas is transmitted from an external gas tank to a gas injection hole formed on an upper portion of a chamber(100). The gas is transmitted to a wafer(106) through a multitude of hole formed on an upper electrode(103). The gas is changed to a plasma state if an RF power is applied between the upper electrode(103) and a lower electrode(104). The wafer(106) is etched by using plasma. The wafer(106) is located on a center portion of the lower electrode(104). The wafer(106) is fixed by a guide ring(107) formed on an edge of the lower electrode(104). A pump(114) is installed at a lower portion of one side of the chamber(100) in order to discharge the etch gas. A convection controller is installed around the lower electrode(104) in order to etch uniformly the wafer(106) by controlling convection within the chamber(100).

Description

Semiconductor plasma etching equipment {Etcing equipment for plasma of semiconductor}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor plasma etching equipment, and more particularly, to plasma etching equipment capable of improving etching uniformity by controlling convection inside a chamber.

As the semiconductor industry develops, semiconductor devices are pursuing high capacity and high functionality, and thus, more devices are required to be integrated in a limited area, and wafer processing technology is being researched and developed to make patterns fine and highly integrated.

Dry etching technology is widely used in the wafer fabrication process for implementing ultra-fine and highly integrated semiconductor devices, and the most common dry etching technology is a plasma application etching method.

However, the etching process using plasma is a very important and difficult technique, and the first considerations in the plasma etching process are etching profile, selectivity with the underlying layer, etching rate and uniformity. And so on. These depend mainly on the characteristics of the etching equipment or feed gas, and in particular, the uniformity is usually influenced by the characteristics of the etching equipment, which is mainly due to uneven pumping, unevenness of helium cooling on ESC and ICP (inductive heating plasma). Circle) depends on the non-uniform electromagnetic field or the like. Apart from the uniformity, the other three things are highly influenced by the characteristics of the feed gas.

Therefore, in order to increase the uniformity, the performance of etching equipment should be improved, and the development and securing of excellent etching equipment are the key to the development of next-generation semiconductors.

Plasma etching equipment is a very important factor in determining the etching performance because the electrode spacing is very small compared to other equipment and the wafer is etched using plasma generated by radio frequency (RF) power. Since the interval between the two is very small, it is difficult to uniformly diffuse the gas supplied from the inlet of the upper chamber, so that only a part of the wafer is etched, which causes a decrease in the uniformity of the etching.

A conventional plasma etching apparatus used for plasma etching will be described with reference to FIG. 1.

Conventional plasma etching equipment, as shown in FIG. 1, is configured to face the upper and lower chambers 20, respectively, to generate a plasma, the upper electrode 24 and the lower electrode 23 and the upper electrode and the lower electrode The RF generator 29 is connected to the outside of the pump 20, and the guide ring 26 and the upper part of the pump 27 for adjusting the pressure inside the chamber 20 and the edge of the lower electrode are fixed to the wafer. An upper electrode assembly 22 supporting the electrode, a gas distribution means formed with a plurality of holes for distributing gas introduced through the gas holes formed in the upper electrode in a wafer direction, and an upper portion of the chamber It consists of a gas injection port 28 used as a path for injecting gas into the interior.

In the etching process using the plasma etching apparatus as described above, first, the wafer is loaded into the chamber to fix the wafer by the guide ring, and the pressure inside the chamber is set to a high vacuum state using a pump.

And a predetermined amount of reaction etching gas is injected through the gas injection port.

Then, the pump is used to adjust the pressure in the chamber to be suitable for the etching process.

However, since the pump structure of the semiconductor plasma etching equipment is formed to be biased on the lower side of the chamber wall, the pressure around the pump is the lowest, and then the pressure is gradually increased in the order of the wafer center and the pump side. There is a problem that the uniformity of the etching rate on the wafer is lowered by the smooth discharge of the plasma and the uneven plasma density.

The object of the present invention is to provide a convection control device located around the lower electrode station in the chamber to solve such problems of the prior art, and by concentrating the convection control device appropriately by an external manipulator, It is to provide a semiconductor plasma etching equipment that can control the above disadvantages.

1 is a cross-sectional view showing the configuration of a conventional semiconductor plasma etching equipment.

2 is a cross-sectional view showing the configuration of a semiconductor plasma etching equipment according to the present invention.

3 (a) to 3 (c) are cross-sectional views of slits provided around the lower electrode in the chamber of FIG.

4 (a) to 4 (c) are cross-sectional views showing the open area of the outer slit in which the slits of FIG. 3 are properly rotated.

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

100,20: chamber 102,22: upper electrode assembly

103, 24: upper electrode 104, 23: lower electrode

106,25 wafer 107,26 guide ring

110,28: gas injection port 112,29: RF generator

114,27: pump 116: ring drive device

130: inner groove 132: outer groove

134: second ring 136: third ring

In order to achieve the above object, the semiconductor plasma etching apparatus of the present invention is configured on the upper side of the chamber and the gas injection unit used as a path for injecting the gas into the chamber, and the upper and lower portions of the chamber are respectively opposed to plasma. Gas distribution means formed with a plurality of holes for distributing gas generated through the upper electrode and the lower electrode and the gas hole formed in the upper electrode and the lower side of the chamber to adjust the pressure inside the chamber A pump and a convection control around the lower electrode station are provided around the lower electrode station so that the incoming gas is biased around the suction-capable pump and does not escape quickly, so that the wafer on the lower electrode is uniform. Allow the etching process to work.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings in order to describe the present invention in more detail.

2 illustrates a configuration of a semiconductor plasma etching apparatus according to the present invention, in which a gas supplied from an external gas cylinder (not shown) is introduced through a gas injection unit 110 formed at the center of an upper portion of the chamber 100. The introduced gas flows downward toward the wafer 106 through a plurality of holes formed in the grounded upper electrode 103, and at this time, RF power is applied between the upper electrode 103 and the lower electrode 104. The principal surface gas is in a plasma state to etch the wafer 106. The wafer is positioned at the center on the lower electrode 104 and is fixed by the guide ring 107 formed at the edge portion of the lower electrode 104.

The lower side of one side of the chamber 100 is provided with a pump 114 for discharging the etching gas. Since the pump 114 is provided only at one lower side of the chamber 100, some surfaces of the wafer 100 around the pump 114 are quickly etched away from the pump 114. Some surfaces of the wafer may be slowly etched so that a uniform etching process is not performed.

In order to solve this problem, a convection control device is provided around the lower electrode 104 station. The convection control device is composed of three rings, and the first ring located at the top is divided into two parts, an inner side and an outer side. It is staggered and has a double structure in which a plurality of rectangular long grooves are dug and arranged at predetermined intervals. The second ring in the middle is located under the first ring, and a plurality of single rectangular long grooves It is arranged at the same interval as the first ring, the lower third ring is divided into two parts inside and outside, the inside is completely open, the outside has a non-uniform open area in the azimuth direction It is in the form, and by adjusting the rotation angle of the second ring and the third ring to control the convection in the chamber 100 to achieve a uniform etching process To help. At this time, by installing an external manipulator 118 on the outside of the chamber 100 to adjust and control the rotation angle from the outside.

Figure 3 (a) shows a first ring 116 located above the three rings, the shape of the first ring 116 is annular, the center of the annular is open. The first ring is divided into an inner groove 130 and an outer groove 132, and a double groove structure in which a plurality of rectangular grooves are arranged at regular intervals in a shape staggered inward and outward. It is.

The first ring 116 is combined with the second ring 134 of FIG. 3 (b) and the third ring 136 of FIG. 3 (c), and thus the second ring 134 and the third ring 136. By rotating to give an appropriate rotation angle, the etching gas due to the suction force of the pump 114, which is biased toward the lower side of the chamber 100, is biased toward the pump 114 immediately without going to the center of the chamber 100 It is possible to improve the unevenness in the etching process caused by exiting.

Fig. 3 (b) shows a second ring which is mounted on the lower part of the first ring and positioned in the middle thereof. The outer shape of the second ring is circular, and the central portion of the circular ring is open. The second ring is composed of a plurality of single slits, the second ring of which the rotation angle is adjusted by the operation of an external program by a stepping motor.

Fig. 3 (c) shows a third ring which is located below the second ring, which has the same shape as the second ring and is designed to have an uneven open area in the azimuth direction. By appropriately rotating according to the convection in the chamber 100 can be controlled.

Similar to the second ring, the third ring is also rotated by the operation of an external program by a stepping motor.

FIG. 4 (a) shows that the outer groove 132 is 100% open by adjusting the rotation angle of the second ring under the first ring, and then the nonuniform close area of the third ring 136 is pumped. Rotation to the side 114 to control the flow of convection in the chamber 100 so that the rapid etching process does not occur only around the pump, the uniform etching process is performed throughout the wafer.

4 (b) gives the second ring 134 an appropriate rotation angle such that the outer groove 130 of the first ring is closed and the inner groove is 100% open.

If the outer groove is not opened as described above, the function of convection control is lost.

FIG. 4 (c) gives a proper rotation angle to the second ring 134 and the third ring 136 so that both the inner groove 130 and the outer groove 132 are open by about 50%.

The reason for opening the inner and outer grooves 132 by about 50% as described above is that the process conditions may vary depending on the pressure in the chamber, the size of the outlet, and the like, so that the pressure in the chamber may be flexibly adjusted according to the process conditions. Because.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

As described above, in the semiconductor plasma etching apparatus according to the present invention, a convection control device is installed at the periphery of the lower electrode to control the convection in the chamber so that there is no difference in etching speed between the center portion of the wafer and the peripheral portion thereof. Ensure uniform etching.

Claims (2)

A gas injection unit configured at an upper portion of the chamber and used as a path for injecting gas into the chamber, and an upper electrode and a lower electrode configured to oppose the upper and lower portions of the chamber to generate plasma; Gas distribution means in which a plurality of holes are formed for distributing gas introduced through the gas holes formed in the upper electrode; A pump provided at one side of the lower side of the chamber to adjust pressure in the chamber; And The convection control device is provided around the lower electrode station so that the introduced gas is biased around the pump with suction force so that it can be uniformly distributed throughout the wafer front without being quickly escaped. Semiconductor plasma etching equipment, characterized in that to achieve. 2. The convection control device as set forth in claim 1, wherein the convection control device is composed of three rings having the same length diameter, and the upper first ring is divided into two parts, the inner and outer parts, and the plurality of long grooves. This digging has a double structure arranged at regular intervals, the second ring in the middle is located at the bottom of the first ring and a plurality of single long grooves are arranged at the same interval as the first ring, The third ring located at is divided into two parts, the inner and outer parts, the inner part is completely open and the outer part has a non-uniform open area in the azimuth direction so that the ring can be controlled from the outside. Semiconductor plasma etching equipment characterized in that it comprises an external manipulator.