KR20060110046A - Shower head and plasma processing apparatus adopting the same - Google Patents

Abstract

A shower head and a plasma processing apparatus using the same are provided to improve the uniformity of reaction without over-etching or over-ashing by controlling the density of plasma using an improved position of a gas spraying hole. A shower head(33) for a plasma processing apparatus comprises a spraying hole forming region(H). The spraying hole forming region is composed of a plurality of spraying holes. The plurality of spraying holes are arranged under a base electrode and a baffle electrode to spray a reaction gas onto an object substrate. The spraying hole forming region is smaller than the object substrate. A first peripheral portion of the spraying hole forming region is arranged within a second peripheral portion of the object substrate.

Description

Shower head and plasma processing apparatus adopting the same

1 is a cross-sectional view showing the configuration of a plasma processing apparatus employing a showerhead according to a preferred embodiment of the present invention.

2 is a plan view schematically showing the configuration of a showerhead according to a preferred embodiment of the present invention.

Figure 3 is a plan view showing an example of partitioning each part of the substrate in order to measure the rate of absorption according to the effect of the showerhead according to a preferred embodiment of the present invention.

Figure 4 is a graph showing the uniformity uniformity of the showerhead according to a preferred embodiment of the present invention compared to the conventional plasma processing apparatus.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a showerhead installed in a plasma processing apparatus, and more particularly, to a showerhead having an improved structure to uniformly distribute gas to a workpiece to be processed in the plasma processing apparatus. The present invention also relates to a plasma processing apparatus employing such a shower head.

Recently, the components of semiconductor devices, LCDs, organic ELs, plasma display panels (PDPs), etc. are becoming more precise. Plasma processing apparatuses are generally used for manufacturing or regenerating the precise components.

Conventional plasma processing apparatus uses an inductively coupled plasma source, a microwave plasma source, or a capacitively coupled plasma source, and generally a capacitively coupled plate. Plasma treatment devices are widely used.

In the capacitively coupled plate plasma processing apparatus, a pair of plate electrodes (upper and lower electrodes) facing each other are provided in the chamber. A vacuum pump or the like is used to increase the degree of vacuum inside the chamber to remove impurities in the chamber, and then a processing gas is introduced into the chamber to maintain an appropriate pressure, and a plasma is formed by applying a high frequency voltage to at least one of the electrodes, thereby treating the object as a substrate. Coating, etching, ashing, cleaning and the like are performed on the water.

In general, the reaction gas is configured to be injected into the chamber from the outside and sprayed onto the substrate to be processed by a shower head positioned below the upper electrode. The gas injected in this way is exhausted through the outlet located in each corner part inside a chamber. However, the injection and flow of these gases has been found to have a significant effect on the etching or etching of the substrate to be processed.

Specifically, in the conventional shower head, injection holes are formed at predetermined intervals over the entire surface, and the area formed with the injection holes is larger than the size of the substrate to be treated to cover the entire substrate. Therefore, part of the injection hole forming region overlaps with the region where the discharge port is located. Such a formation structure of the injection hole causes concentration of the processing gas in the vicinity of the discharge port, thereby increasing the density of the reaction gas, thereby causing excessive etching of the substrate to be processed.

In the above configuration, the flow rate of the gas at the center of the showerhead (that is, the center of the substrate to be processed) has a large difference from the flow rate of gas at the edge of the showerhead (that is, the outlet opening position). . That is, the velocity deviation according to this position means that a uniform flow of gas is not guaranteed, and thus the substrate is not uniformly etched / etched and local overetching may occur.

This phenomenon also causes a large difference between the long and short sides of the substrate. That is, in the case of a conventional LCD substrate, since the rectangular shape having a long side and a short side edge is not square, the shower head also has a rectangular shape accordingly. In this case, the path of the gas injected from the center of the shower head to the outlet via the short side of the substrate is longer than the path toward the outlet via the long side. Thus, the flow rate and density of the gas at the short side edge of the substrate increases, resulting in over-etching due to re-reaction.

Typically, the etching uniformity of the substrate requires an error within 10%, but the etching uniformity of the substrate generally exceeds 15 to 20% due to the above problems. In particular, in recent years, since the LCD substrate and the like is gradually increasing in size, such nonuniformity causes more serious results. In conclusion, there is a need for a method of ensuring the uniformity of etching of the substrate by allowing the gas injected from the showerhead to flow uniformly.

The present invention has been devised to solve the above problems, and improves the etching / etch uniformity of the workpiece by varying the injection hole formation density at the long side and the short side of the substrate so that the gas is uniformly distributed. It is an object of the present invention to provide a showerhead for a plasma processing apparatus.

Still another object of the present invention is to provide a plasma processing apparatus employing the shower head as described above.

In order to achieve the above object, a shower head for a plasma processing apparatus according to the present invention is arranged in parallel to a base electrode and a baffle electrode in a chamber of a plasma processing apparatus, and to inject a reaction gas to a substrate to be processed. In the shower head for a plasma processing apparatus having an injection hole forming region (H) in which a plurality of injection holes are formed from an upper surface to a lower surface,

The outline of the injection hole forming region H is positioned inside the outline of the substrate so that the area of the injection hole forming region H is smaller than the area of the substrate to be processed.

Preferably, the outer corners of the injection hole forming region H have a tapered or rounded shape so as not to overlap with the discharge holes located in the corners of the plasma processing apparatus.

More preferably, the injection hole forming region H has a long side L and a short side S respectively corresponding to the long side and the short side of the substrate to be processed, and the long side passing through the center in the short side S. The formation density of the injection holes increases from the central portion S1 near La to the peripheral portion S2.

More preferably, the injection hole formation density is increased discontinuously or continuously.

According to the present invention, a closed sealing groove is formed at an edge of the shower head, and is coupled to the base electrode with a sealing member interposed in the sealing groove.

According to another aspect of the invention, the chamber is composed of an upper cover and a lower body for receiving a substrate to be processed; A base electrode disposed under the upper cover and formed with a gas passage through which a reaction gas supplied from an external gas supply part flows, and spaced apart from the base electrode by a predetermined distance, and flows through the gas passage of the base electrode; A plurality of injection holes for injecting a baffle electrode formed with a plurality of through holes so as to pass through the reaction gas, and a reaction gas arranged at a lower distance from the baffle electrode and passed through the through holes of the baffle electrode to the substrate to be processed. An upper electrode assembly including a shower head having the injection hole forming region H formed therein; A lower electrode positioned at the bottom of the lower body; And a discharge port positioned at a corner portion of the chamber to discharge the reaction gas, wherein the area of the injection hole forming area H is smaller than the area of the substrate to be processed. A plasma processing apparatus having an outline positioned inward of an outline of the substrate to be processed is provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 shows a schematic configuration of a plasma processing apparatus according to a preferred embodiment of the present invention.

Referring to the drawings, the plasma processing apparatus according to the present embodiment includes a chamber 100 including an upper cover 10 and a lower main body 20. The substrate to be processed is introduced into the chamber 100, and the inside of the chamber 100 may be maintained in a vacuum state while being sealed by a sealing.

Electrodes for generating plasma by the reaction gas are installed in the chamber 100. Specifically, an upper electrode assembly 30 is disposed below the upper cover 10, and a lower electrode is disposed on the bottom of the lower body 20. 40).

The upper electrode assembly 30 may include a base electrode 31 positioned below the upper cover 10, a baffle electrode 32 spaced apart from the base electrode 31 by a predetermined interval, and the baffle; The shower head 33 is spaced apart from the electrode 32 by a predetermined distance. To maintain the spacing between the base electrode 31 and the baffle electrode 32 and between the baffle electrode 32 and the showerhead 33 while supporting the baffle electrode 32 and the showerhead 33 respectively. A plurality of spacers 51 and 52 are coupled therebetween.

The base electrode 31 is formed with a gas passage 31a for introducing a reaction gas supplied from an external gas supply unit (not shown), which is a gas inlet formed in the upper cover 10 of the chamber 100. It is connected with 10a. Therefore, the reaction gas supplied from the outside through the gas injection port 10a and the gas passage 31a is directed to the baffle electrode 32. The base electrode 31 is supported at its edge by an insulator 56 such as ceramic or engineering plastic.

In addition, a high frequency voltage is applied to the base electrode 31 from an external power source (not shown), which is transmitted to the baffle electrode 32.

For example, the baffle electrode 32 may be fixed to the base electrode 31 by coupling fastening means such as a bolt 53 to a fastening hole formed at an edge thereof.

In addition, although not shown in detail in the drawing, a plurality of through holes are formed in the baffle electrode 31, and the reaction gas flowing through the base electrode 31 passes therethrough and flows downward.

Shower head 33 according to the present invention is arranged side by side under the baffle electrode 32, a plurality of fastening holes 301 are formed along the edge portion thereof, as shown in FIG. 301 is fixed to the base electrode 31 by coupling fastening means such as bolt 54.

Preferably, a closed sealing groove 302 is formed at the edge of the shower head 33, and the sealing groove 302 is provided with a sealing member (55 in FIG. 1) such as an O-ring. It is to be coupled to the base electrode 31 while making it. Therefore, the reaction gas introduced into the chamber 100 is prevented from leaking unnecessarily at the coupling point between the base electrode 31 and the shower head 33 to induce concentration on the substrate to be processed.

The shower head 33 according to the present invention is formed with a plurality of injection holes 303 penetrating from the upper surface to the lower surface. Therefore, as shown in FIG. 1, after the gas flows through the gas injection port 10a and the gas passage 31a from the outside, the gas that reaches the shower head 33 through the through hole of the baffle electrode 32 is It is injected onto the substrate through the injection hole 303.

In FIG. 2, the region indicated by the dotted line indicates the 'spray hole forming region H' in which the injection holes 303 are formed on the shower head 33.

In the present embodiment, the outline of the injection hole forming region H is a closed curve and has a long side L and a short side S, respectively. The long side L corresponds to the long side of the substrate (not shown), and the short side S is a portion corresponding to the short side of the substrate.

According to the present invention, the injection hole forming region H is smaller than the region occupied by the substrate. That is, the outline of the injection hole forming region H is located inward of the outline of the substrate (reference numeral 200 indicated by a dashed line). The distance D between the outline of the injection hole forming region H and the outline 200 of the substrate is preferably at least 5 to 10% of the width of the substrate and 9 to 12% of the length of the substrate. Do. In this way, by reducing the area of the area where the injection hole is formed to be smaller than the area of the substrate, it is possible to prevent the phenomenon in which the gas is concentrated at the edges or sides of the substrate and the density increases.

In addition, in the shower head 33 of the present invention, injection holes are not formed at each corner portion where the discharge port (not shown) is located. Therefore, the outline of the injection hole forming region H is tapered or rounded at the corner of the shower head 33. Preferably, the outline corner portion of the injection hole forming region H is configured not to overlap at least with the region in which the discharge hole is formed (reference numeral 60 indicated by a circular dotted line). This is to solve the drawback of the conventional showerhead, in which the injection holes of the showerhead are overlapped at the position where the discharge port is formed, thereby causing the nonuniformity of the gas flow.

Further, in the short side S of the injection hole forming region H, the formation density of the injection holes (injection per unit area) from the central portion S1, i.e., the region near the long axis La passing through the center, to the peripheral portion S2. The number of holes formed) increases.

At this time, the injection hole forming density may be increased discontinuously at any point as shown in Figure 2, as another alternative, may be continuously increased.

This arrangement of injection holes eventually contributes to reducing the unevenness of etching and etching at the short edge of the substrate.

Features and effects of the present invention will be more clearly understood through the following experimental examples.

Experimental Example

The same substrate was treated in a plasma chamber with a showerhead according to the invention and a plasma chamber with a conventional showerhead as a comparative example. At this time, the capacity of the plasma chamber is 430 liters (liter), the internal pressure is maintained at 620 mTorr, the gas residence time is 3.83 sec. The substrate to be processed is a TFT-glass for a wide viewing angle LCD having a size of 1200 x 1300 mm.

The size of the showerhead according to the comparative example is 1302 × 1402 mm, in which 1845 injection holes having a diameter of 0.5 mm are formed. The space | interval between each injection hole is 30 mm x 30 mm, and is comprised so that the whole to-be-processed board | substrate may be covered. Oxygen and helium were used as reaction gases for plasma treatment, and 8.5 kw of 13.56 MHz power was applied for the plasma reaction, and the reaction proceeded for 75 sec.

The size of the shower head and the diameter of the injection hole and the distance between the injection holes according to the present invention are the same as in the comparative example, but the injection hole forming region H is 85% wide and 78.5% long compared to the substrate (that is, the horizontal gap D). = 7.5% of the board length, vertical gap D = 10.6% of the board length), and a total of 1,156 injection holes are formed. At this time, the injection hole forming region (H) has a shape as shown in FIG.

After the plasma treatment was performed under the above conditions, as shown in FIG. 3, the respective portions of the substrate were partitioned and the ashing rate of each substrate in the area indicated by each number was measured.

4 is a graph showing the result of calculating the edge deviation according to the edge rate measured in each region. As can be seen from the graph, while the substrate processed in the plasma chamber with a conventional shower head about ethylene deviation of about 28% occurs, it can be seen that the deviation is significantly reduced as 10% in the present invention.

In the case of a shower head with a uniformly uniform gas injection hole, the transition gas flow and more viscous flow characteristics ensure that sufficient RF energy is supplied to form plasma with increasing hourly density of gas at the short side and at the corner of the shower head. As a result, the etching or etching rate increased with the increase of the density of the plasma. In the case of the showerhead before the improvement, the uniformity of the etching and etching was inhibited due to the irregular distribution of gas flow rate and density at the four corners of the showerhead, but this problem was also improved.

Plasma processing apparatus having a showerhead according to the present invention, by changing the position of the gas injection hole in the showerhead has the effect of adjusting the density of the plasma can be made to react uniformly without excessive etching or etching. have.

Claims (10)

Plasma arranged side by side under the base electrode and the baffle electrode in the chamber of the plasma processing apparatus, the plasma having the injection hole forming region (H) formed with a plurality of injection holes from the upper surface to the lower surface to inject the reaction gas to the substrate to be processed In the shower head for the processing apparatus, Wherein the outline of the injection hole forming region H is located inside the outline of the substrate so that the area of the injection hole forming region H is smaller than the area of the substrate to be processed. Shower head. The method of claim 1, An outline corner portion of the injection hole forming region (H) has a tapering or round shape so as not to overlap with an outlet located in a corner portion of the plasma processing apparatus. The method of claim 1, The injection hole forming region (H), It has a long side (L) and a short side (S) respectively corresponding to the long side and short side of the substrate to be processed, In the short side (S), the shower head for the plasma processing apparatus, characterized in that the density of the injection hole formed increases from the central portion (S1) near the long axis (La) passing through the center toward the peripheral portion (S2). The method of claim 3, The spray hole forming density is a showerhead for a plasma processing apparatus, characterized in that the discontinuously increasing or continuously increasing. The method of claim 1, A closed sealing groove is formed at the edge of the shower head, Shower head for a plasma processing apparatus, characterized in that coupled to the base electrode with a sealing member interposed in the sealing groove. A chamber composed of an upper cover and a lower body and containing a substrate to be processed; A base electrode disposed under the upper cover and formed with a gas passage through which a reaction gas supplied from an external gas supply part flows, and spaced apart from the base electrode by a predetermined distance, and flows through the gas passage of the base electrode; A plurality of injection holes for injecting a baffle electrode formed with a plurality of through holes so as to pass through the reaction gas, and a reaction gas arranged at a lower distance from the baffle electrode and passed through the through holes of the baffle electrode to the substrate to be processed. An upper electrode assembly including a shower head having the injection hole forming region H formed therein; A lower electrode positioned at the bottom of the lower body; And It includes a discharge port located in the corner in the chamber for discharging the reaction gas, Wherein the outline of the injection hole forming region H is located inside the outline of the substrate so that the area of the injection hole forming region H is smaller than the area of the substrate to be processed. . The method of claim 6, An outline corner portion of the injection hole forming region (H) has a tapering or round shape so as not to overlap with an outlet located at a corner portion inside the chamber. The method of claim 6, The injection hole forming region (H), It has a long side (L) and a short side (S) respectively corresponding to the long side and short side of the substrate to be processed, In the short side (S), the plasma processing apparatus, characterized in that the formation density of the injection hole increases from the central portion (S1) near the long axis (La) passing through the center toward the peripheral portion (S2). The method of claim 8, And the injection hole forming density is increased discontinuously or continuously. The method of claim 6, A closed sealing groove is formed at the edge of the shower head, And a sealing member interposed between the sealing groove and the base electrode.

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