KR20190001394U - 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 areas of the substrate as well as the edges of the substrate. In order to compensate for non-uniformities, it is also possible to increase the deposition on the substrate in regions of the substrate underlying the gas distribution plate, as needed, to allow more gas to flow through certain strategically placed gas passages, Can be sized differently. The orifice size may be varied to create a gradient of mixing of diameters or orifice diameters, resulting in a substantially uniform deposition.

Description

Technical Field [0001] The present invention relates to a 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 dispensing gas in a processing chamber.

Liquid crystal displays or flat panels are commonly used for active matrix displays such as computers and television monitors. Plasma enhanced chemical vapor deposition (PECVD) is generally employed to deposit thin films on a substrate, such as a flat panel display or a transparent substrate for a semiconductor wafer. PECVD is generally accomplished by introducing a precursor gas or gas mixture into a vacuum chamber containing the 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 (e.g., excited) into the plasma. The excited gas or gas mixture reacts to form a layer of material on the surface of a substrate positioned on a temperature controlled substrate support. The volatile byproducts produced during the reaction are pumped through the exhaust system from the chamber.

The plates processed by PECVD techniques are typically large and often exceed 4 square meters. The gas distribution plates (or gas diffuser plates) utilized to provide a uniform process gas flow over the plates are particularly advantageous when compared to gas distribution plates utilized for 200 mm and 300 mm semiconductor wafer processing , The size is relatively large. In addition, since the substrates are rectangular, the edges of the substrate, such as the sides and corners of the substrate, experience conditions that may differ from the conditions 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, film thickness and film uniformity control 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 of the substrate and the edges, becomes important.

Thus, there is a need for an improved gas distribution plate assembly that improves film properties and film deposition thickness uniformity.

The present invention generally relates to gas distribution plates designed to ensure substantially uniform deposition on a substrate. The gas distribution plate can compensate for non-uniformities in the corner areas of the substrate as well as the edges of the substrate. In order to compensate for non-uniformities, it is possible to increase the deposition on the substrate in regions of the substrate that are under the gas distribution plate, so that more gas is allowed to flow through certain strategically positioned gas passages, The orifices of the gas passages may be sized differently. The orifice size may be varied to create a gradient of the mixing of the diameters or the orifice diameters, resulting in a substantially uniform deposition.

In one embodiment, a diffuser for a deposition chamber includes a plate having edge zones and corner zones, and a plurality of gas passages formed between an upstream side and a downstream side of the plate, Wherein a portion of the plurality of gas passages in either or both of the edge zones and the corner zones comprises 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, wherein the first diameter is greater 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 zone opposing a second major edge zone, a minor edge zone adjacent each of the first and second major edge zones, a major edge zone, 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 one or both of the major edge zones and the corner zones The formed gas passages include a local flow gradient structure.

A more particular description of the invention, briefly summarized above, in such a manner that the recited features of the present invention can be understood in detail, may be made with reference to the embodiments, some of which are illustrated in the accompanying drawings . It should be noted, however, that the appended drawings illustrate only typical embodiments of this invention and, therefore, should not be construed as limiting the scope of the present invention, as this invention may permit other equally effective embodiments to be.

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

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that the elements and features of one embodiment may be advantageously 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 areas of the substrate as well as the edges of the substrate. According to the 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 a greater flow rate through portions of the gas distribution plate relative to other portions of the gas distribution plate, to compensate for non-uniformities . In one aspect, an orifice of the gas passageway is provided, as needed, so as to allow more gas to flow through certain strategically placed gas passageways to increase deposition on the substrate in regions of the substrate underlying the gas distribution plate. Can be sized differently. The orifice size may be varied to form a gradient of the mixing of the diameters or the diameter of the orifices, resulting in a substantially uniform deposition.

Embodiments of the present disclosure are illustratively described below 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. However, it will be appreciated that the present invention may be of use in other system configurations, such as etching systems, other chemical vapor deposition systems, and any other system where gas distribution is required in a process chamber, including systems configured to process circular substrates. It should be understood.

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

The chamber 100 generally includes walls 102, a bottom 104, and a gas distribution plate or diffuser 110, and a substrate support 130, which define a process volume 206. The process volume 106 is accessed through the 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 for raising and lowering the substrate support 130 . The shadow frame 133 may be disposed above the periphery of the substrate 105 during processing. Lift pins 138 are movably disposed through the substrate support 130 to move the substrate 105 to and from the substrate receiving surface 132 to facilitate substrate transfer . 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 its diffuser 110 by a suspension 114. The diffuser 110 may also be supported by one or more center supports 116 to assist in controlling the straightness / curvature of the diffuser 110 and / May be coupled to the plate (112). The gas source 120 is coupled to the backing plate 112 via a backing plate 112 to a plurality of gas passages 111 formed in the diffuser 110 and to the gas receiving surface 132 . A vacuum pump 109 is coupled to the chamber 100 for controlling the pressure in the process volume 106. The RF power source 122 is coupled to a diffuser 110 to generate an electric field between the substrate support 130 and the diffuser 110 such that a plasma can be formed from gases existing between the substrate support 130 and the diffuser 110. [ Is coupled to diffuser 110 and / or backing plate 112 to provide RF power to antenna 110. Various RF frequencies, such as frequencies from about 0.3 MHz to about 200 MHz, may be used. In one embodiment, the RF power source 122 provides power to the spreader 110 at a frequency of 13.56 MHz.

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

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

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 may range from 400 mils to about 1,200 mils, . In one embodiment, the bottom surface 140 of the diffuser 110 may include a concave curvature that is thinner than the peripheral region of its diffuser 110, as shown in the cross-sectional view of FIG.

The chamber 100 is fabricated by depositing silicon oxide (SiO _x ), which is widely used as gate insulator films, buffer layers for thermal dissipation, and etch stop layers in TFTs and AMOLEDs, with nitrous oxide (N ₂ O) in the diluted silane (SiH ₄₎ can be used to deposit the gas. The uniformity (i.e., 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. Minimal edge rejection, as well as film uniformity of about 5% or less across the surface of the substrate. Much progress has been made towards this goal, but there are zones of the substrate where such uniformity is not achieved. For example, the edges of the substrate, such as the corner regions and sides of the substrate, experience a lower deposition rate, which results in film thicknesses in these regions that are smaller than other regions. Although not wishing to be bound by theory, the cause of the lower deposition rates in the edge zones is due to gas distribution and / or electromagnetic field variations near these areas. To overcome these effects and minimize non-uniformities in the films formed on the substrate 105, the inventive diffuser 110 has been developed and tested.

2 is a cross-sectional view of a portion of the diffuser 110 of FIG. The diffuser 110 includes a first or upstream side 202 facing the backing plate 112 (shown in FIG. 1) and a second or downward facing (toward the substrate support 130) Stream side 204 as shown in FIG. Each gas passageway 111 is connected to a first bore 210 coupled by an orifice hole 214 in a second bore 212 that is combined to form a fluid path through the diffuser 110 . The first bore 210 extends from the upstream side 202 of the diffuser 110 to the bottom 218 to a first depth 230. The bottom portion 218 of the first bore 210 may be tapered to minimize flow restriction when gases flow from the first bore 210 into the orifice hole 214, Be chamfered, beveled, chamfered, or rounded. ≪ RTI ID = 0.0 > The first bore 210 generally has a diameter of about 0.093 to about 0.218 inches, and in one embodiment is about 0.156 inches.

The thickness of the 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 from about 0.1 inch to about 1.0 inch. The diameter 236 of the second bore 212 is generally about 0.1 inch to about 1.0 inch and can be flared at an angle 216 of about 10 degrees to about 50 degrees. In one embodiment, the diameter 236 is from about 0.1 inch to about 0.5 inch, and the widened angle 216 is from about 20 degrees to about 40 degrees. The surface of the second bore 212 is about 0.05 square inches to about 10 square inches, and in one embodiment is 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 x 1850 mm substrates has second bores 212 at a diameter of 0.250 inches and a widened angle 216 of about 22 degrees. The distances 280 between the rims 282 of the adjacent second bores 212 are from about 0.0 inch to about 0.6 inch, and in one embodiment from about 0.0 inch to about 0.4 inch. The diameter of the first bore 210 is generally at least equal to the diameter of the second bore 212 or less than the diameter of the second bore 212, but is not limited thereto. The bottom 220 of the second bore 212 can be tapered or tapered to minimize the pressure loss of the gases exiting the orifice hole 214 and flowing into the second bore 212, Or may be rounded. Moreover, because the proximity of the orifice hole 214 to the downstream side 204 serves to minimize the exposed surface area of the downstream side 204 and second bore 212 towards the substrate, The downstream area 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 portion 218 of the first bore 210 and the bottom portion 220 of the second bore 212. Orifice hole 214 typically has a diameter of from about 0.01 inch to about 0.3 inch, such as from about 0.01 inch to about 0.1 inch, and typically from about 0.02 inch to about 1.0 inch, such as from about 0.02 inch to about 0.5 inch And a length 234. The length 234 and diameter (or other geometric property) of the orifice hole 214 may promote or even distribute the even distribution of gas across the upstream side 202 of the diffuser 110 Is the main source of back pressure in the volume between the backing plate 112 and the diffuser 110 (shown in Fig. 1). Orifice hole 214 is typically configured uniformly between a plurality of gas passages 111 but may be configured to facilitate more gas flow through one region or region of diffuser 110 relative to other regions or zones, The restriction through the orifice hole 214 can be configured differently between the gas passages 111. [ For example, orifice holes 214 may be formed in the processing chamber 100 such that more gas flows through the edges of the diffuser 110 to increase the deposition rate at portions of the peripheral regions of the substrate 105 Or shorter length 234 in the gas passages 111 of the diffuser 110 closer to the wall 102 (shown in FIG.

3 is a cross-sectional top view of the diffuser 110 of FIGS. 1 and 2 showing internally formed orifice holes 214. FIG. The diffuser 110 includes four adjacent sides 300A through 300D connected at the corners 305A through 305D. The sides 300A and 300C define the major edges of the diffuser 110 while the sides 300B and 300D define the minor edges of the diffuser 110. [

Region 310 is displayed by the dashed line bent on the side 300A of the diffuser 110. [ The region 310 includes a region of the diffuser 110 in which the orifice holes 214 include a flow restraining property that is different from the other orifice holes 214 in the diffuser 110. [ One or all of the sides 300B-300D may include the region 310, although the region 310 is shown only on the side 300A. The diffuser 110 also includes a region 315 indicated by a dashed line curved near the corner 305A. The region 315 includes a region of the diffuser 110 in which the orifice holes 214 contain a flow restraining property that is different from the other orifice holes 214 in the diffuser 110. One or all of the corners 305B through 305D may include the region 315, although the region 315 is shown near the corner 305A.

The regions 310 and 315 may define portions of the diffuser 110 where a local flow gradient is provided in accordance with the embodiments described herein. The local flow gradient may comprise a structure composed of one or more orifice holes 214 having different flow restraining properties than the 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 the other orifice holes 214 in the diffuser 110. [ The localized flow gradient may include a structure comprised 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 comprised of a group of orifice holes 214 having a first diameter adjacent other orifice holes 214 having a second diameter, the second diameter being different from the first diameter Do. Additionally, the local flow gradient may comprise a structure comprised of groups of one or more orifice holes 214 having a first diameter interspersed within other orifice holes 214 having a second diameter And the second diameter is different from the first diameter.

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

5 is a cross-sectional top view of a portion of diffuser 110 of FIG. 3, showing one embodiment of region 315. FIG. 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 an aspect, the diameters of the first orifice holes 505A are about 20% to about 30% greater than the diameters 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 top view of a portion of diffuser 110 of FIG. 3, showing another embodiment of region 315. FIG. In this embodiment, a plurality of first orifice holes 605A is shown disposed around the plurality of second orifice holes 605B, 605C, and 605D, which constitutes another embodiment of the 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, a portion of the second orifice holes has a diameter that is about 20% to about 30% greater than the diameter of 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 both 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 remainder of the second orifice holes 605C and 605D and the first orifice holes 605A, The remainder of the holes 605C and 605D are the same size.

Embodiments of the diffuser 110 with various orifice holes as described herein compensate for lower deposition rates and increase gas flow over the corner areas and / or edge areas of the substrates. Thereby, the total film thickness uniformity is improved. The diffuser 110 may be fabricated in accordance with the embodiments described herein, or orifice holes as described herein may be added to existing diffusers in a retrofit process.

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

It is to be understood that the foregoing is directed to embodiments of the present invention, but other and further embodiments of the present invention may be devised without departing from the basic scope thereof, and the scope of the present invention is determined by the following claims.

Claims (16)

A diffuser for a deposition chamber,
A plate having edge zones and corner zones and a plurality of gas passages formed between an upstream side and a downstream side of the plate,
Wherein a portion of the plurality of gas passages in either or both of the edge zones and the corner zones comprises a first orifice hole having a first diameter and a second orifice hole having a second diameter, And the remaining plurality of orifice holes include a third diameter, the first diameter being greater than the second diameter and the third diameter,
Diffuser. The method according to claim 1,
Wherein the first diameter is about 30% greater than the third diameter,
Diffuser. The method according to claim 1,
And the remaining plurality of orifice holes comprise a fourth diameter that is smaller than the third diameter.
Diffuser. The method of claim 3,
The second diameter and the third diameter being substantially the same,
Diffuser. The method of claim 3,
Wherein the first diameter is about 30% greater than the fourth diameter,
Diffuser. 6. The method of claim 5,
The second diameter and the third diameter being substantially the same,
Diffuser. The method according to claim 6,
The second diameter and the third diameter being about 20% greater than the fourth diameter,
Diffuser. 8. The method of claim 7,
Wherein the first diameter is about 30% greater than the fourth diameter,
Diffuser. The method according to claim 1,
Wherein a portion of the plurality of gas passages in the edge zones are located in one or more of the first rows of first orifice holes and in one or more first rows of the first orifice holes And one or more second rows of positioned second orifice holes.
Diffuser. A diffuser for a deposition chamber,
A plate having a first major edge zone opposing a second major edge zone;
A minor edge zone adjacent each of said first and second major edge zones;
A corner zone at the intersection of the major edge zones and the minor edge zones; And
A plurality of gas passages formed between the upstream side and the downstream side of the plate
/ RTI >
The gas passages formed in one or both of the major edge zones and the corner zones may include a local flow gradient structure,
Diffuser. 11. The method of claim 10,
Wherein the local flow gradient structure comprises a first orifice hole having a first diameter and a second orifice hole having a second diameter and the remaining plurality of orifice holes comprise a third diameter, Diameter and the third diameter,
Diffuser. 12. The method of claim 11,
Wherein the first diameter is about 30% greater than the third diameter,
Diffuser. 12. The method of claim 11,
And the remaining plurality of orifice holes comprise a fourth diameter that is smaller than the third diameter.
Diffuser. 14. The method of claim 13,
The second diameter and the third diameter being substantially the same,
Diffuser. 14. The method of claim 13,
Wherein the first diameter is about 30% greater than the fourth diameter,
Diffuser. 16. The method of claim 15,
The second diameter and the third diameter being substantially the same,
Diffuser.

Images