JP2004349375A - Gas dispersing plate of dry etching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the gas dispersing plate of a dry etching apparatus which improves uniformity of an etching speed in a wafer surface by uniformly controlling a reaction gas supplied to the wafer with simple configuration without raising an apparatus cost. <P>SOLUTION: The gas dispersing plate of the dry etching apparatus includes the gas dispersing plate 17 newly provided between an upper electrode 3 and a gas blowing plate 7 for uniformly dispersing the reaction gas in a treating chamber 6. Many dispersing holes 18 of openings are formed in the gas dispersing plate 17. The dispersing holes 18 are disposed at positions not superposed with blowing holes 9 formed in the gas blowing plate 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas dispersion plate of a dry etching apparatus for etching a semiconductor wafer (hereinafter, referred to as a wafer) using a plasma of a reactive gas in a vacuum processing chamber, and more particularly, to a flow rate of a reactive gas supplied to the processing chamber. The present invention relates to a gas dispersion plate for uniformity.
[0002]
[Prior art]
In a semiconductor device manufacturing process, a dry etching apparatus using plasma is used to remove a predetermined film formed on the surface of a wafer. The principle of this apparatus is that a reaction gas is activated into ions or radicals in a plasma atmosphere, reacts with a predetermined film, and etching is performed by evaporating a reaction product.
[0003]
Such a technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-55172. 4A and 4B are a cross-sectional view of a conventional dry etching apparatus and a plan view of a gas blowing plate used for the same. In a conventional dry etching apparatus 41 shown in FIG. 4A, an upper electrode 43 and a lower electrode 44 are arranged in a chamber 42 so as to face each other, and a wafer 45 to be etched is placed on the lower electrode 44. Have been. A gas blowing plate 47 for supplying a reaction gas into the processing chamber 46 and a ring-shaped anode cover 48 for fixing the gas blowing plate 47 to the upper electrode 43 are attached to the upper electrode 43. The gas blowing plate 47 has a large number of blowing holes 49 formed therein. Further, the upper electrode 43 is hollow and a reaction gas is supplied to the inside thereof, and a gas supply pipe 50, a supply valve 51, a gas flow rate adjusting unit 52, and a gas supply source 53 are connected.
[0004]
Usually, when the wafer 45 is etched by the dry etching apparatus 41,
After a predetermined amount of reaction gas is supplied from the gas supply source 53 to the processing chamber 46 via the gas flow control unit 52 and the supply valve 51 in the processing chamber 46, a high-frequency voltage is applied between the upper electrode 43 and the lower electrode 44. The applied and introduced reaction gas is plasma ionized, and the wafer 45 is etched by the impact energy of the ions.
[0005]
However, when etching is performed using the above-described conventional dry etching apparatus 41, a difference occurs in the etching rate between the central portion and the outer peripheral portion of the wafer 45, and it is difficult to perform uniform etching in the plane of the wafer 45. .
[0006]
This is because the gas supply pipe 50 is fixed to the center of the upper electrode 43, so that the flow rate of the reaction gas is inevitably maximized near the center of the upper electrode 43, and becomes smaller toward the outer periphery. to cause. A gas blowing plate 47 shown in FIG. 4B is provided between the upper electrode 43 and the processing chamber 46, and the reaction gas is dispersed into the processing chamber 46 through the blowing holes 49 of the gas blowing plate 47. However, since all the blowing holes 49 are formed with the same diameter, the flow rate of the reaction gas discharged from the gas supply pipe 50 cannot be completely and uniformly dispersed in the processing chamber 46. The flow rate difference of the reaction gas as shown by the arrow 54 occurs. Here, the length of the arrow 54 indicates the flow rate of the reaction gas. As a result, the etching progresses quickly at the center of the wafer 45, and the uniformity of the etching rate in the plane of the wafer 45 is impaired. In particular, as the size of the wafer 45 to be processed increases, the etching rate within the wafer 45 varies greatly.
[0007]
In order to solve this problem, other dry etching apparatuses have been proposed in the above-described related art. FIGS. 5A and 5B are a cross-sectional view of the dry etching apparatus and a plan view of a gas blowing plate used for the apparatus.
[0008]
In a dry etching apparatus 61 shown in FIG. 5A, an upper electrode 63 and a lower electrode 64 are arranged in a chamber 62 so as to face each other, and a wafer 65 to be etched is placed on the lower electrode 64. I have. A gas outlet plate 67 for supplying a reaction gas into the processing chamber 66 and a ring-shaped anode cover 68 for fixing the gas outlet plate 67 to the upper electrode 63 are attached to the upper electrode 63. Further, as shown in FIG. 5B, a large number of blow holes 69 are formed in the gas blow plate 67.
[0009]
The upper electrode 63 is hollow and a reaction gas is supplied to the inside thereof. Three gas supply pipes 70a to 70c, three supply valves 71a to 71c, and respective supply valves 71a to 71c are provided. Is connected to a gas flow source 73 and a gas flow control unit 72 for controlling the flow rate. Further, the hollow portion of the upper electrode 63 is partitioned by partition walls 74a and 74b into diffusion chambers 75a to 75c for supplying a reaction gas independently from the three gas supply pipes 70a to 70c.
[0010]
In the operation of the dry etching apparatus 61, a gas concentration distribution between the upper electrode 63 and the lower electrode 64 is measured by a gas sensor (not shown) provided in the chamber 62. Then, the supply valves 71a to 71c are adjusted by the gas flow rate adjusting unit 72 so that the gas concentration distribution becomes uniform, and the flow rate of the reaction gas supplied to each of the diffusion chambers 75a to 75c is adjusted. Next, a high-frequency voltage is applied between the upper electrode 63 and the lower electrode 64 to etch the wafer 65, thereby making the etching rate in the plane of the wafer 65 uniform.
[0011]
[Patent Document 1]
JP-A-5-55172 (page 2, 0002 to 0011, FIGS. 1 and 3)
[0012]
[Problems to be solved by the invention]
However, the above-described dry etching apparatus 61 has the following problems. In order to make the flow rate of the reaction gas uniform over the entire surface of the wafer 65, a large number of diffusion chambers 75a to 75c that partition the inside of the upper electrode 63 finely are required. Furthermore, depending on the number of the diffusion chambers 75a to 75c, the gas supply pipes 70a to 70c, the supply valves 71a to 71c, the gas flow rate adjustment unit 72, and the gas sensor are also required, so that the mechanism becomes complicated, and the apparatus becomes extremely complicated. There is a problem that it becomes expensive.
[0013]
The present invention has been conceived in order to solve the above-mentioned problems, and it is possible to uniformly control the flow rate of a reaction gas supplied to a wafer with a simple apparatus configuration without increasing the apparatus cost, thereby performing etching in a wafer plane. An object of the present invention is to provide a gas dispersion plate with improved speed uniformity.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a gas dispersion plate of a dry etching apparatus according to claim 1 of the present invention includes an upper electrode and a lower electrode which are arranged opposite to each other at a predetermined interval in a chamber, and wherein the upper electrode A gas distribution plate used in a dry etching apparatus for introducing a reaction gas into a processing chamber from a gas blowing plate attached to the substrate and generating a plasma between both electrodes to process a material to be etched, wherein the gas distribution plate is A position provided between the upper electrode and the gas blowing plate to make the flow rate of the reaction gas uniform, and an opening formed in the gas dispersion plate does not overlap with a blowing hole formed in the gas blowing plate. It is characterized by being arranged in. According to this configuration, since the opening of the gas dispersion plate and the blowout hole of the gas blowout hole are arranged so as not to overlap with each other, the reaction gas dispersed from the gas supply pipe through the opening of the gas dispersion plate, Further, the reaction gas distributed through the blowout holes of the gas blowout plate and having a uniform flow rate can be supplied into the processing chamber.
[0015]
According to a second aspect of the present invention, in the gas distribution plate of the dry etching apparatus according to the first aspect, the opening formed in the gas distribution plate is provided on the same circumference. It is characterized by comprising a number of dispersion holes, wherein the diameters of the dispersion holes are all the same. According to this configuration, since the dispersion holes of the adjacent gas dispersion plates and the blowout holes of the gas blowout plate are arranged so as not to overlap with each other, the reaction gas supplied from the gas supply pipe flows through the dispersion holes of the gas dispersion plate. The reaction gas is dispersed through the gas outlet plate, and further dispersed through the outlet of the gas outlet plate, so that a reaction gas having a uniform flow rate can be supplied into the processing chamber.
[0016]
According to a third aspect of the present invention, in the gas distribution plate of the dry etching apparatus according to the first aspect, an opening formed in the gas distribution plate is provided on the same circumference. The gas dispersion plate is formed of a large number of dispersion holes, and the diameter of the dispersion holes increases from the center to the outer periphery of the gas dispersion plate. According to this configuration, since the diameter of the dispersion holes formed in the gas dispersion plate is changed according to the flow distribution of the reaction gas supplied from the gas supply pipe, the reaction gas having a more uniform flow rate is supplied into the processing chamber. it can.
[0017]
According to a fourth aspect of the present invention, there is provided the gas distribution plate of the dry etching apparatus according to the first aspect, wherein the opening formed in the gas distribution plate is provided on the same circumference. It is characterized by comprising a number of dispersion grooves, wherein the width of the dispersion grooves increases from the center to the outer periphery of the gas dispersion plate. According to this configuration, the width of the dispersion groove formed in the gas dispersion plate is changed according to the flow rate distribution of the reaction gas flowing out of the gas supply pipe, so that the reaction gas having a more uniform flow rate can be supplied into the processing chamber.
[0018]
According to a fifth aspect of the present invention, there is provided a gas distribution plate for a dry etching apparatus according to the first aspect, wherein the opening formed in the gas distribution plate is a central portion of the gas distribution plate. And a radially extending groove extending from the center of the gas distribution plate to the outer peripheral portion. According to this configuration, the width of the radial dispersion grooves formed in the gas dispersion plate is changed in accordance with the flow rate distribution of the reaction gas flowing out of the gas supply pipe, so that the reaction gas having a more uniform flow rate can be supplied into the processing chamber. .
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIGS. 1A to 1C are a cross-sectional view of a dry etching apparatus according to a first embodiment of the present invention and a plan view of a gas dispersion plate and a gas blowing plate used for the same. In the dry etching apparatus 1 shown in FIG. 1A, an upper electrode 3 and a lower electrode 4 are arranged in a chamber 2 so as to face each other, and a wafer 5 to be etched is placed on the lower electrode 4. I have. A gas outlet plate 7 for supplying a reaction gas into the processing chamber 6 and a ring-shaped anode cover 8 for fixing the gas outlet plate 7 to the upper electrode 3 are attached to the upper electrode 3. A large number of blow holes 9 are formed in the gas blow plate 7.
[0020]
The upper electrode 3 is supplied with a gas therein, and is connected to a gas supply pipe 10, a supply valve 11, a gas flow control unit 12, and a gas supply source 13. On the other hand, a gas exhaust pipe 14, an exhaust valve 15, and an exhaust pump 16 are connected to a lower portion of the chamber 2.
[0021]
Further, a gas dispersion plate 17 for uniformly dispersing the reaction gas in the processing chamber 6 is newly provided between the upper electrode 3 and the gas blowing plate 7. As shown in FIG. 1B, the gas distribution plate 17 has a large number of distribution holes 18 as openings. The dispersion holes 18 are arranged so as not to overlap with the blowout holes 9 formed in the gas blowout plate 7 shown in FIG. 1C, and are formed so that the diameters X1 of the dispersion holes 18 are all the same. ing. Note that the + mark in FIG. 1B indicates the position of the blowout hole 9.
[0022]
Next, the operation of the dry etching apparatus 1 will be described. First, after adsorbing and holding the wafer 5 on the lower electrode 4, the inside of the chamber 2 is evacuated by the exhaust pump 16. Next, a reaction gas whose flow rate is controlled by the gas flow control valve 12 is introduced from the gas supply source 13 to the upper electrode 2 via the gas supply pipe 10. The introduced reaction gas is dispersed throughout by passing through the dispersion holes 18 of the gas dispersion plate 17.
[0023]
The reaction gas that has passed through the dispersion holes 18 of the gas dispersion plate 17 is further dispersed throughout and supplied to the processing chamber 6 by passing through the blow holes 9 of the gas blow plate 7. In this way, while supplying the reaction gas into the processing chamber 6, the gas is exhausted by the exhaust pump 16 through the gas exhaust pipe 14, and the inside of the chamber 2 is maintained at a predetermined pressure state. Thereafter, a high-frequency voltage is applied between the upper electrode 2 and the lower electrode 3 to generate plasma in a space above the lower electrode 3, and a desired plasma process is performed on the wafer 5 on the lower electrode 3. The gas generated by the reaction is exhausted from the gas exhaust pipe 14 to the outside of the chamber 2 together with the remaining reaction gas.
[0024]
As described above, since the gas dispersion plate 17 of the present invention is arranged so that the dispersion holes 18 do not overlap the blowout holes 9 of the gas blowout plate 7, the gas dispersion plate 17 is dispersed through the dispersion holes 18 of the gas dispersion plate 17. The reactant gas is further dispersed throughout through the blowout holes 9 of the gas blowout plate 7, and as shown by the arrow 19, the gas flow rates at the central portion and the outer peripheral portion become substantially equal. Here, the length of the arrow 19 indicates the flow rate of the reaction gas. As a result, a reaction gas having a more uniform flow rate than before is supplied to the wafer 5, and the variation in the etching rate in the plane of the wafer 5 is greatly improved. Further, since the gas dispersion plate 17 can be attached and detached and can be easily replaced and washed, it is excellent in maintainability and does not require a complicated mechanism, so that the apparatus cost is reduced.
[0025]
Next, another preferred embodiment will be described with reference to the drawings. 2 (a) to 2 (c) are a sectional view of a dry etching apparatus according to a second embodiment of the present invention and a plan view of a gas dispersion plate and a gas blowing plate used therein. In FIG. 2, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted. The difference between the first embodiment and the first embodiment is that the diameter of a large number of dispersion holes, which are openings of a gas dispersion plate, is increased from the center to the outer periphery in order to accommodate a large-sized wafer. The reason for this is that the dispersion of the reaction gas is made more uniform by forming it to be large.
[0026]
As shown in FIG. 2A, a gas dispersion plate 22 for uniformly dispersing the reaction gas in the processing chamber 6 is provided between the upper electrode 3 and the gas blowing plate 7 in the dry etching apparatus 21. . Further, as shown in FIG. 2B, a large number of dispersion holes 23 as openings are formed in the gas dispersion plate 22. The dispersion holes 23 are arranged at positions other than the upper portions of the blowout holes 9 formed in the gas blowout plate 7 shown in FIG. Further, the diameter X2 of the dispersion holes 23 is formed so as to increase from the center to the outer periphery of the gas dispersion plate 22. Note that the + mark in FIG. 2B indicates the position of the blowout hole 9.
[0027]
As described above, according to the gas dispersion plate 22 used in the dry etching apparatus 21 of the present invention, the diameter of the dispersion holes 23 formed in the gas dispersion plate 22 is adjusted according to the flow rate distribution of the reaction gas flowing out of the gas supply pipe 10. Changing. That is, since the hole diameter at the central portion where the gas flow rate is large is small and the hole diameter where the gas flow rate is small is large, a reaction gas with a more uniform flow rate can be supplied into the processing chamber 6. As a result, the flow rate of the reaction gas that has passed through the gas dispersion plate 22 and the gas blowing plate 7 is supplied to the wafer 5 while being made more uniform than in the first embodiment, and the variation in the etching rate in the plane of the wafer 5 is further increased. Be improved.
[0028]
In addition, the gas dispersion plate 22 of the dry etching apparatus 21 for making the flow rate of the reaction gas uniform in the present embodiment is not limited to the shape shown in FIG. For example, a shape as shown in FIGS. 3A and 3B can be used. FIG. 3A shows that a plurality of dispersion grooves 32 as openings are formed on the same circumference of the gas dispersion plate 31, and the width X3 of the dispersion grooves 32 is changed from the center to the outer periphery of the gas dispersion plate 31. It is formed so that it becomes larger as it goes. FIG. 3B shows a case where a radial dispersion groove 34 extending from the center of the gas dispersion plate 33 to the outer periphery is formed, and the width X4 of the radial dispersion groove 34 as an opening is set to the center of the gas dispersion plate 33. It is formed so as to increase from the portion to the outer peripheral portion. Note that the + marks in FIGS. 3A and 3B indicate the positions of the blowout holes 9. Even with such a configuration, the area of the central opening having a large gas flow rate can be reduced and the area of the peripheral opening having a small gas flow rate can be increased, so that a reaction gas having a more uniform flow rate can be supplied into the processing chamber. And the etching rate in the wafer surface can be made uniform. In addition, the number and size of the dispersion holes or grooves in the gas dispersion plate can be appropriately adjusted according to the flow rate of the reaction gas, and the material of the gas dispersion plate may be a ceramic material or the like having the same quality as the gas blowing plate. it can.
[0029]
【The invention's effect】
As described above, according to the gas distribution plate of the dry etching apparatus of the present invention, a gas distribution plate is newly provided between the upper electrode and the gas blowing plate, and the opening formed in the gas distribution plate is formed in the gas blowing plate. Since the reaction gas is arranged so as not to overlap with the formed blow-out hole and the reaction gas is passed through the gas dispersion plate and the gas blow-out plate, the reaction gas can be more uniformly supplied to the wafer than in the past, and the wafer can be supplied in a plane. Can greatly reduce the etching variation.
[0030]
In addition, the opening formed in the gas distribution plate is constituted by a dispersion hole, a dispersion groove, a radial dispersion groove, and the like, and the diameter and the width thereof are increased from the center to the outer periphery of the gas dispersion plate. The reaction gas can be more uniformly supplied to the wafer. As a result, even when the size of the wafer is large, the variation in etching in the plane of the wafer can be further reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a dry etching apparatus according to a first embodiment of the present invention and a plan view of a gas dispersion plate and a gas blowing plate used therein. FIG. 2 is a cross-sectional view of a dry etching apparatus according to a second embodiment of the present invention. FIG. 3 is a plan view of a gas dispersion plate and a gas blow-out plate used therein. FIG. 3 is a plan view of a gas dispersion plate of another embodiment of the present invention. FIG. 4 is a cross-sectional view of a conventional dry etching apparatus and gas used therein. FIG. 5 is a cross-sectional view of another conventional dry etching apparatus and a plan view of a gas blowing plate used for the apparatus.
DESCRIPTION OF SYMBOLS 1 Dry etching apparatus 2 of the first embodiment of the present invention 2 Chamber 3 Upper electrode 4 Lower electrode 5 Wafer 6 Processing chamber 7 Gas blowout plate 8 Anode cover 9 Blowout hole 10 Gas supply pipe 11 Supply valve 12 Gas flow control unit 13 Gas supply Source 14 Gas exhaust pipe 15 Exhaust valve 16 Exhaust pump 17 Gas dispersion plate 18 Dispersion hole 19 according to the first embodiment of the present invention Arrow 21 Dry etching apparatus 22 according to the second embodiment of the present invention 22 Gas according to the second embodiment of the present invention Dispersion plate 23 Dispersion hole 31 Gas dispersion plate 32 of another embodiment of the present invention Dispersion groove 33 Gas dispersion plate 34 of another embodiment of the present invention Radial dispersion groove 41 Conventional dry etching apparatus 42 Chamber 43 Upper electrode 44 Lower electrode 45 Wafer 46 Processing chamber 47 Gas blowout plate 48 Anode cover 49 Blowout hole 50 Gas supply pipe 51 Supply valve 52 Gas flow rate adjustment 53 Gas supply source 54 Arrow 61 Other conventional dry etching apparatus 62 Chamber 63 Upper electrode 64 Lower electrode 65 Wafer 66 Processing chamber 67 Gas blowout plate 68 Anode cover 69 Blowout holes 70a to 70c Gas supply pipes 71a to 71c Supply valve 72 Gas flow controller 73 Gas supply sources 74a, 74b Partition walls 75a to 75c Diffusion chamber

Claims (5)

An upper electrode and a lower electrode are disposed in the chamber so as to face each other at a predetermined interval, and a reaction gas is introduced into the processing chamber from a gas blowing plate attached to the upper electrode, and plasma is generated between the two electrodes. A gas distribution plate of a dry etching apparatus for processing a material to be etched, wherein the gas distribution plate is provided between the upper electrode and the gas blowing plate to make a flow rate of the reaction gas uniform, and A gas dispersion plate for a dry etching apparatus, wherein an opening formed in the dispersion plate is arranged so as not to overlap with a blowout hole formed in the gas blowout plate. 2. An opening formed in the gas dispersion plate is composed of a large number of dispersion holes provided on the same circumference, and the diameters of the dispersion holes are all the same. A gas dispersion plate for the dry etching apparatus as described in the above. The opening formed in the gas dispersion plate is composed of a large number of dispersion holes provided on the same circumference, so that the diameter of the dispersion hole increases from the center to the outer periphery of the gas dispersion plate. The gas dispersion plate for a dry etching apparatus according to claim 1, wherein the gas dispersion plate is formed. The opening formed in the gas dispersion plate is composed of a large number of dispersion grooves provided on the same circumference, so that the width of the dispersion groove increases from the center to the outer periphery of the gas dispersion plate. The gas dispersion plate for a dry etching apparatus according to claim 1, wherein the gas dispersion plate is formed. The opening formed in the gas dispersion plate is composed of radial dispersion grooves extending from the center of the gas dispersion plate to the outer periphery, and the width of the radial dispersion groove is increased from the center of the gas dispersion plate to the outer periphery. 2. The gas dispersion plate for a dry etching apparatus according to claim 1, wherein the gas dispersion plate is formed so as to increase as the temperature increases.

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