KR200491450Y1 - Gas diffuser hole design for improving edge uniformity - Google Patents

Abstract

The present invention generally relates to a gas distribution plate designed to ensure a substantially uniform deposition on a substrate. The gas distribution plate can compensate for non-uniformities in the corner regions of the substrate as well as the edges of the substrate. To compensate for non-uniformities, the gas passage, if necessary, is allowed to allow more gas to flow through certain strategically arranged gas passages to increase deposition on the substrate in areas of the substrate underlying the gas distribution plate. The orifice of may be sized differently. The orifice size can be varied to form a mixture of diameters or a gradient of orifice diameters, resulting in a substantially uniform deposition.

Description

Gas diffuser hole design to improve edge uniformity {GAS DIFFUSER HOLE DESIGN FOR IMPROVING EDGE UNIFORMITY}

Embodiments of the present invention generally relate to a gas distribution plate assembly, and a method for distributing gas in a processing chamber.

Liquid crystal displays or flat panels are commonly used for active matrix displays such as computer and television monitors. Plasma enhanced chemical vapor deposition (PECVD) is generally employed to deposit thin films on a substrate, such as a transparent substrate for a flat panel display or semiconductor wafer. PECVD is generally accomplished by introducing a precursor gas or gas mixture into a vacuum chamber containing a substrate. The precursor gas or gas mixture is typically directed downward through a distribution plate located near the top of the chamber. By applying radio frequency (RF) power to the chamber from one or more RF sources coupled to the chamber, the precursor gas or gas mixture in the chamber is energized (eg, excited) with plasma. The excited gas or gas mixture reacts to form a layer of material on the surface of the substrate located on a temperature controlled substrate support. Volatile byproducts produced during the reaction are pumped from the chamber through an exhaust system.

Plates processed by PECVD techniques are typically large and often exceed 4 square meters. Gas distribution plates (or gas diffuser plates) utilized to provide a uniform process gas flow over the plates are compared to gas distribution plates utilized for 200 mm and 300 mm semiconductor wafer processing, in particular. , The size is relatively large. Additionally, because the substrates are rectangular, the edges of the substrate, such as the sides and corners of the substrate, experience conditions that may differ from those experienced in other parts of the substrate. . These different conditions affect processing parameters such as film thickness, deposition uniformity, and / or film stress.

As the size of substrates continues to increase in the flat panel display industry, controlling film thickness and film uniformity for large area PECVD becomes a problem. Thin film transistors (TFT) and active matrix organic light emitting diodes (AMOLED) are only two types of devices for forming flat panel displays. The difference in film properties and / or deposition rate such as film thickness or stress between the center and edges of the substrate becomes important.

Accordingly, a need exists for an improved gas distribution plate assembly that improves film properties and uniformity of film deposition thickness.

The present invention generally relates to a gas distribution plate designed to ensure a substantially uniform deposition on a substrate. The gas distribution plate can compensate for non-uniformities in the corner regions of the substrate as well as the edges of the substrate. To compensate for non-uniformities, as required, to allow more gas to flow through certain strategically arranged gas passages to increase deposition on the substrate in areas of the substrate underlying the gas distribution plate. The orifice of the gas passage can be sized differently. The orifice size can be varied to form a mixture of diameters or a gradient of orifice diameters, resulting in a substantially uniform deposition.

In one embodiment, the diffuser for the deposition chamber comprises a plate having edge regions and corner regions, and a plurality of gas passages formed between the upstream side and downstream side of the plate, Here, in one or both edge zones and corner zones, a portion of the plurality of gas passages includes a first orifice hole having a first diameter and a second orifice hole having a second diameter, The remaining plurality of orifice holes include a third diameter, the first diameter being larger than the second diameter and the third diameter.

In another embodiment, a diffuser for a deposition chamber is provided. The diffuser includes a plate having a first major edge region opposing the second major edge region, a minor edge region adjacent to each of the first and second major edge regions, and major edge regions. A corner zone at the intersection of minor edge zones, and a plurality of gas passages formed between the upstream and downstream sides of the plate, wherein either or both of the major edge zones and the corner zones The gas passages formed include a local flow gradient structure.

A more detailed description of the present invention, which has been briefly summarized above, can be made with reference to the embodiments in a way that the above-listed features of the present invention can be understood in detail, some of which are illustrated in the accompanying drawings. . It should be noted, however, that the appended drawings are merely illustrative of exemplary embodiments of the present invention and should not be regarded as limiting the scope of the present invention, since the present invention may allow other equally effective embodiments. to be.

1 is a schematic cross-sectional view of one embodiment of a PECVD chamber.
2 is a cross-sectional view of a portion of the diffuser of FIG. 1;
3 is a cross-sectional plan view of the diffuser of FIGS. 1 and 2;
4 is a cross-sectional plan view of a portion of the diffuser of FIG. 3;
5 is a cross-sectional plan view of a portion of the diffuser of FIG. 3, showing one embodiment of a corner region.
6 is a cross-sectional plan view of a portion of the diffuser of FIG. 3, showing another embodiment of a corner region.

For ease of understanding, the same reference numbers have been used where possible to indicate the same elements that are common to the drawings. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation.

The present invention generally relates to a gas distribution plate designed to ensure a substantially uniform deposition on a substrate. The gas distribution plate can compensate for non-uniformities in the corner regions of the substrate as well as the edges of the substrate. According to embodiments described herein, the gas distribution plate compensates for non-uniformities by adjusting the flow of gases through the gas distribution plate in areas where deposition is non-uniform. In one embodiment, the local flow gradient in one or more portions of the gas distribution plate is adjusted to provide greater flow through the portions of the gas distribution plate compared to other portions of the gas distribution plate to compensate for non-uniformities. You can. In one aspect, the orifice of the gas passage, if necessary, is allowed to allow more gas to flow through certain strategically positioned gas passages to increase deposition on the substrate in areas of the substrate underlying the gas distribution plate. It can be sized differently. The orifice size can be varied to form a mixture of diameters or a gradient of orifice diameters, resulting in a substantially uniform deposition.

In connection with a PECVD system configured to process large area substrates, such as a PECVD system available from AKT, a division of Applied Materials, Inc. of Santa Clara, California, embodiments of the present specification are illustratively described below. However, the present invention finds utility in other system configurations, such as etching systems, other chemical vapor deposition systems, and any other system requiring gas distribution within the process chamber, including systems configured to process circular substrates. It should be understood that it has.

1 is a schematic cross-sectional view of one embodiment of a PECVD chamber 100 for forming electronic devices such as TFT and AMOLED. It is noted that FIG. 1 is merely an exemplary apparatus that can be used to form electronic devices on a substrate. One suitable PECVD chamber is available from Applied Materials, Inc. located in Santa Clara, California. It is contemplated that other deposition chambers may be utilized to practice the present invention, including those from other manufacturers.

The chamber 100 generally includes walls 102, a bottom 104, and a gas distribution plate or diffuser 110, which defines the process volume 206, and a substrate support 130. The process volume 106 is accessed through a sealable slit valve 108 formed through the walls 102 so that the substrate can be transferred into and out of the chamber 100. The substrate support 130 includes a substrate receiving surface 132 for supporting the substrate 105 and a stem 134 coupled to the lift system 136 to raise and lower the substrate support 130. . The shadow frame 133 can be disposed over the periphery of the substrate 105 during processing. To facilitate substrate transfer, lift pins 138 are movably disposed through the substrate support 130 to move the substrate 105 to and from the substrate receiving surface 132. . The substrate support 130 may also include heating and / or cooling elements 139 to maintain the substrate support 130 and the substrate 105 positioned thereon at a desired temperature. The substrate support 130 may also include ground straps 131 to provide RF ground to the periphery of the substrate support 130.

The diffuser 110 is coupled to the backing plate 112 at the periphery of the diffuser 110 by the suspension 114. The diffuser 110 is also backed by one or more center supports 116 to assist in controlling the straightness / curvature of the diffuser 110 and / or preventing sagging. It may be coupled to the plate 112. The gas source 120 couples to the backing plate 112 to provide gas through the backing plate 112 to a plurality of gas passages 111 formed in the diffuser 110 and to the substrate receiving surface 132. Ring. Vacuum pump 109 is coupled to chamber 100 to control the pressure in process volume 106. The RF power source 122 is a diffuser to generate an electric field between the substrate support 130 and the diffuser 110 so that plasma can be formed from gases present between the substrate support 130 and the diffuser 110. To provide RF power to 110, it is coupled to diffuser 110 and / or backing plate 112. Various RF frequencies can be used, such as frequencies from about 0.3 MHz to about 200 MHz. In one embodiment, RF power source 122 provides power to diffuser 110 at a frequency of 13.56 MHz.

A remote plasma source 124, such as an inductively coupled remote plasma source, can also be coupled between the gas source 120 and the backing plate 112. Between the processing of the substrates, a cleaning gas can be provided to a remote plasma source 124 and excited to form a remote plasma, from which the dissociated cleaning gas species is generated, and chamber components It is provided for cleaning. The cleaning gas may be further excited by an RF power source 122 provided to flow through diffuser 110 to reduce recombination of dissociated cleaning gas species. Suitable cleaning gases include, but are not limited to, NF ₃ , F ₂ , and SF ₆ .

In one embodiment, heating and / or cooling elements 139 may be utilized to maintain the temperature of the substrate support 130 and the substrate 105 thereon during deposition to about 400 ° C or less. In one embodiment, heating and / or cooling elements 139 may be used to control the substrate temperature to less than 100 ° C, such as from 20 ° C to about 90 ° C.

The spacing during deposition between the top surface of the substrate 105 disposed on the substrate receiving surface 132 and the bottom surface 140 of the diffuser 110 is 400 mils to about 1,200 mils, such as 400 mils to about 800 mils You can. In one embodiment, the bottom surface 140 of the diffuser 110 may include a concave curvature in which the central region is thinner than the peripheral region of the diffuser 110, as shown in the cross-sectional view of FIG. 1.

The chamber 100 employs silicon oxide (SiO _x ), which is widely used as gate insulator films, buffer layers for heat dissipation, and etching stop layers in TFTs and AMOLEDs, by a PECVD process, nitrous oxide (N ₂ It can be used to deposit with silane (SiH ₄ ) gas diluted in O). The uniformity (ie, thickness) of the oxide film has a significant impact on the final device performance, such as mobility and drain current uniformity, and is therefore important in the development of the process. Minimum edge exclusion, as well as film uniformity of about 5% or less across the surface of the substrate is required. Although much progress has been made towards this goal, there are areas of the substrate where this uniformity is not achieved. For example, edges of the substrate, such as corner regions and sides of the substrate, experience a lower deposition rate, which results in film thicknesses in these regions, which are smaller than other regions. Without wishing to be bound by theory, the cause of the lower deposition rate in edge regions is due to gas distribution and / or electromagnetic field changes near these regions. In order to overcome these effects and minimize non-uniformities in the films formed on the substrate 105, the diffuser 110 of the present invention has been developed and tested.

2 is a cross-sectional view of a portion of the diffuser 110 of FIG. 1. The diffuser 110 includes a first or upstream side 202 facing the backing plate 112 (shown in FIG. 1), and an opposite second or down facing substrate support 130 (shown in FIG. 1). Includes stream side 204. Each gas passage 111 is coupled to a first bore 210 coupled by an orifice hole 214 to a second bore 212 that is combined to form a fluid path through the diffuser 110. Is defined by The first bore 210 extends to the first depth 230 from the upstream side 202 of the diffuser 110 to the bottom 218. The bottom 218 of the first bore 210 can be tapered to minimize flow restriction when gases flow from the first bore 210 into the orifice hole 214, or It can be beveled, chamfered, or rounded. The first bore 210 generally has a diameter of about 0.093 to about 0.218 inches, and in one embodiment, about 0.156 inches.

The thickness of diffuser 110 is from about 0.8 inches to about 3.0 inches, such as from about 0.8 inches to about 2.0 inches. A second bore 212 is formed in the diffuser 110 and extends from the downstream side (or end) 204 to a depth 232 of about 0.10 inches to about 2.0 inches. In one embodiment, the depth 232 is between about 0.1 inches and about 1.0 inches. The diameter 236 of the second bore 212 is generally from about 0.1 inches to about 1.0 inches, and can be flared at an angle 216 of about 10 ° to about 50 °. In one embodiment, the diameter 236 is from about 0.1 inches to about 0.5 inches, and the angle 216 is 20 ° to about 40 °. The surface of the second bore 212 is from about 0.05 square inches to about 10 square inches, and in one embodiment, from about 0.05 square inches to about 5 square inches. The diameter of the second bore 212 refers to the diameter that intersects the downstream surface 204. An example of a diffuser 110 used to process 1500 mm × 1850 mm substrates has a diameter of 0.250 inches and second bores 212 at a wide angle 216 of about 22 °. Distances 280 between rims 282 of adjacent second bores 212 are from about 0.0 inches to about 0.6 inches, and in one embodiment, from about 0.0 inches to about 0.4 inches. The diameter of the first bore 210 is generally at least equal to the diameter of the second bore 212 or smaller than the diameter of the second bore 212, but is not limited thereto. The bottom 220 of the second bore 212 can be tapered, inclined, or chamfered to minimize pressure loss of gases exiting the orifice hole 214 and flowing into the second bore 212. Can be, or can be rounded. Moreover, because the proximity of the orifice hole 214 to the downstream side 204 functions to minimize the exposed surface area of the downstream side 204 and the second bore 212 facing the substrate, the chamber The downstream region of the diffuser 110 exposed to fluorine provided during cleaning is reduced, thereby reducing the occurrence of fluorine contamination of the deposited films.

The orifice hole 214 generally couples the bottom 218 of the first bore 210 and the bottom 220 of the second bore 212. The orifice hole 214 generally has a diameter of from about 0.01 inches to about 0.3 inches, such as from about 0.01 inches to about 0.1 inches, and typically from about 0.02 inches to about 1.0 inches, such as from about 0.02 inches to about 0.5 inches. It has a length 234. The length 234 and diameter (or other geometrical attributes) of the orifice hole 214 promotes an even distribution of gas across the upstream side 202 of the diffuser 110 (FIG. It is the main source of back pressure in the volume between the backing plate 112 and the diffuser 110 (shown in 1). The orifice hole 214 is typically constructed uniformly between a plurality of gas passages 111, but to promote more gas flow through one region or zone of the diffuser 110 compared to other regions or zones, The suppression through the orifice hole 214 can be configured differently between the gas passages 111. For example, the orifice hole 214 is shown in the processing chamber 100 (FIG. 1) to allow more gas to flow through the edges of the diffuser 110 to increase deposition rate in portions of the perimeter regions of the substrate 105. May have a larger diameter and / or shorter length 234 in the gas passages 111 of the diffuser 110 closer to the wall 102).

3 is a cross-sectional plan view of diffuser 110 of FIGS. 1 and 2, showing orifice holes 214 formed therein. The diffuser 110 includes four adjacent sides 300A-300D connected at corners 305A-305D. Sides 300A and 300C define major edges of diffuser 110, while sides 300B and 300D define minor edges of diffuser 110.

The region 310 is displayed by a broken dashed line on the side 300A of the diffuser 110. Region 310 includes a region of diffuser 110 in which orifice holes 214 contain different flow suppression properties than other orifice holes 214 in diffuser 110. Although the region 310 is only shown on the side 300A, one or all of the sides 300B to 300D may include the region 310. The diffuser 110 also includes an area 315 indicated by a broken dashed line near the corner 305A. Region 315 includes a region of diffuser 110 in which orifice holes 214 include different flow suppression properties than other orifice holes 214 in diffuser 110. Although region 315 is shown near corner 305A, one or all of corners 305B to 305D may include region 315.

Regions 310 and 315 may define portions of diffuser 110 provided with a local flow gradient according to embodiments described herein. The local flow gradient may include a structure composed of one or more orifice holes 214 having different flow suppression properties from other orifice holes 214 in the diffuser 110. The local flow gradient may be provided by one or more orifice holes 214 having a diameter different from the diameter of other orifice holes 214 in diffuser 110. The local flow gradient can include a structure composed of one orifice hole 214 having a first diameter surrounded by other orifice holes 214 having a second diameter, the second diameter being different from the first diameter Do. The local flow gradient may also include a structure consisting of a group of orifice holes 214 having a first diameter adjacent to other orifice holes 214 having a second diameter, the second diameter being different from the first diameter Do. Additionally, the local flow gradient may include a structure composed of groups of one or more orifice holes 214 having a first diameter interspersed in other orifice holes 214 having a second diameter. And the second diameter is different from the first diameter.

4 is a cross-sectional plan view of a portion of the region 310 of the diffuser 110 of FIG. 3. A plurality of orifice holes 405, 410, 415, 420, 425, and 430 are shown representing one embodiment of the orifice holes 214 shown in FIG. Rows 1-6 are shown as sub-regions 400 of region 310 and orifice holes 405, 410, 415 with different flow suppression properties that make up one embodiment of a local flow gradient structure. , 420, 425, and 430). The orifice holes 405 may be included in row 1, and may include a first diameter larger than the diameter of the orifice holes 410 in row 2. Orifice holes 415 may be included in row 3 and may include a second diameter that is larger than the diameter of orifice holes 420 in row 4. In one embodiment, the first diameter of the orifice holes may be about 30% larger than the diameter of the orifice hole n of the diffuser 110 with the smallest diameter. In other embodiments, the second diameter may be about 20% larger than the diameter of the orifice hole n of the diffuser 110 with the smallest diameter. In one embodiment, the diameter (ie, minimum diameter) of the orifice hole n of the diffuser 110 is from about 17 mils to about 22 mils, such as from about 18 mils to 20 mils. Patterns of differences in diameter of orifice holes 405, 410, 415, 420, 425, and 430 can vary within region 310. In one embodiment, the diameter of the orifice holes 405, 410, 415, 420, 425, and 430 decreases from the side 300A within the region 310 toward the center of the diffuser 110. In another embodiment, orifice holes 405 include a first diameter that is greater than the diameter of one or a combination of orifice holes 410, 415, 420, 425, and 430. In another embodiment, multiple selected rows in sub-region 400 have one or a diameter similar to the diameter of orifice holes 405 larger than orifice holes 410, 415, 420, 425, and 430. It may include two or more orifice holes. In other embodiments, orifice holes 405, 410, 415, 420, 425, and 430 having different diameters may be mixed within each of rows 1-6.

5 is a cross-sectional plan view of a portion of diffuser 110 of FIG. 3, showing one embodiment of region 315. The plurality of first orifice holes 505A is shown surrounded by a plurality of second orifice holes 505B having a second diameter, which constitutes another embodiment of the local flow gradient structure. In one embodiment, the second diameter is smaller than the first diameter. In one aspect, the diameters of the first orifice holes 505A are about 20% to about 30% larger than the diameter of the second orifice holes 505B. In one embodiment, the plurality of first orifice holes 505A includes a cluster 510, and one or more of these clusters 510 may be included in the region 315.

6 is a cross-sectional plan view of a portion of diffuser 110 of FIG. 3, showing another embodiment of region 315. In this embodiment, a plurality of second orifice holes 605B, 605C, and 605D are shown disposed around the plurality of first orifice holes 605A, which constitute another embodiment of a local flow gradient structure. do. In one embodiment, each of the first orifice holes 605A includes a diameter that is smaller than the diameter of each of the second orifice holes 605B, 605C, and 605D. In another embodiment, some of the second orifice holes have a diameter of about 20% to about 30% greater than the diameter of the first orifice holes 605A. In another embodiment, the diameter of some of the second orifice holes, such as orifice holes 605B, is greater than the diameter of both the rest of the second orifice holes 605C and 605D and the first orifice holes 605A. In another embodiment, the diameter of a portion of the second orifice holes, such as orifice holes 605B, is greater than the diameter of the remainders 605C and 605D of the second orifice holes and the first orifice holes 605A, and the second orifice The rest of the holes 605C and 605D are the same size.

Embodiments of diffuser 110 with various orifice holes as described herein compensate for low deposition rates on corner regions and / or edge regions of substrates and increase gas flow. Thereby, the overall film thickness uniformity is improved. The diffuser 110 may be manufactured according to the embodiments described herein, or orifice holes as described herein may be added to an existing diffuser in a retrofit process.

The corner areas of the diffuser similar to the diffuser 110 were tested, and the diffuser of the present invention exhibited a 15% increase in deposition rate. In addition, as a result, the corner diagonal profile at the corner with one enlarged orifice hole improved from 96% to 98% at 15 mm edge exclusion.

Although the foregoing relates to the embodiments of the present invention, other and additional embodiments of the present invention may be devised without departing from the basic scope of the present invention, and the scope of the present invention is determined by the following claims.

Claims (16)

As a diffuser for the deposition chamber,
A plate having side zones and corner zones, and a plurality of gas passages formed between an upstream side and a downstream side of the plate,
Some of the plurality of gas passages in the corner zones include a first orifice hole having a first diameter, and some of the plurality of gas passages in the side zones have one or more rows. And each row has a first orifice hole having the first diameter and a second orifice hole having a second diameter, and the remaining plurality of orifice holes comprises a third diameter,
A plurality of first orifice holes having a first diameter form a cluster in the corner regions, the periphery being surrounded by a plurality of second orifice holes having a second diameter,
The first diameter is larger than the second diameter and the third diameter, thereby comparing the gas flow rate through the second orifice hole of the side zones and the gas flow rate through the remaining plurality of orifice holes, The gas flow rate through the first orifice hole is further increased,
The first diameter of the first orifice holes in the one or more rows is greater than the second diameter of the second orifice holes in the rest of the one or more rows,
Diffuser. According to claim 1,
The first diameter is 30% larger than the third diameter,
Diffuser. According to claim 1,
The remaining plurality of orifice holes include a fourth diameter smaller than the third diameter,
Diffuser. The method of claim 3,
The second diameter and the third diameter are the same,
Diffuser. The method of claim 3,
The first diameter is 30% larger than the fourth diameter,
Diffuser. The method of claim 5,
The second diameter and the third diameter are the same,
Diffuser. The method of claim 6,
The second diameter and the third diameter are 20% larger than the fourth diameter,
Diffuser. According to claim 1,
The one or more rows of the plurality of gas passages in the side zones, one or more first rows of the first orifice holes having the first diameter, and one or more of the first orifice holes Comprising one or more second rows of second orifice holes having the second diameter located inside the first rows,
Diffuser. A diffuser for a deposition chamber,
A plate having a first major side zone opposing the second major side zone;
A minor side zone adjacent to each of the first and second major side zones;
A corner section at the intersection of the major side sections and the minor side sections; And
And a plurality of gas passages formed between the upstream side and the downstream side of the plate.
Gas passages formed in one or both of the major side zones and the corner zones include a local flow gradient structure,
The local flow gradient structure is:
A first plurality of first orifice holes formed in the corner zones and having a first diameter,
A first plurality of second orifice holes formed in side regions and having a second diameter, and
The remaining plurality of orifice holes having a third diameter
It includes,
A second plurality of first orifice holes having a first diameter forms a cluster in the corner zones, the perimeter being surrounded by a second plurality of second orifice holes having a second diameter,
The first diameter is larger than the second diameter and the third diameter, thereby comparing the gas flow rate through the second orifice hole of the side zones and the gas flow rate through the remaining plurality of orifice holes, The gas flow rate through the first orifice hole is further increased,
Each of the major side zones has one or more first rows of first orifice holes having the first diameter and the second diameter located inside one or more first rows of the first orifice holes Comprising one or more second rows of second orifice holes,
Diffuser. The method of claim 9,
The first diameter is 30% larger than the third diameter,
Diffuser. The method of claim 9,
The remaining plurality of orifice holes include a fourth diameter smaller than the third diameter,
Diffuser. The method of claim 11,
The second diameter and the third diameter are the same,
Diffuser. The method of claim 11,
The first diameter is 30% larger than the fourth diameter,
Diffuser. The method of claim 13,
The second diameter and the third diameter are the same,
Diffuser.
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