Wafer processing apparatus with auxiliary ground path

Abstract

A wafer processing apparatus with improved film uniformity is presented. The apparatus includes a radio frequency (RF) housing enclosing and defining a reaction chamber; a showerhead disposed within the reaction chamber, the showerhead configured to generate plasma for processing the wafer in the reaction chamber; a radio frequency (RF) power source configured to generate RF and supply the generated RF to the showerhead; a plurality of capacitors connected in parallel and / or in series between the RF power source and the showerhead; and one or more auxiliary ground lines configured to be placed over the showerhead. The auxiliary ground lines will be sequentially turned on to improve the graph profile.

Description

Technical Field

[0001] The present invention relates to a wafer processing apparatus, and more particularly to a wafer processing apparatus capable of improving wafer non-uniformity by controlling an electric field using an auxiliary ground path located above a shower head. Background Art

[0002] Wafer processing equipment using VHF (very high frequency) plasma may have new process potential with high film quality at low temperatures.

[0003] However, for VHF CCP (capacitively coupled plasma) reactors used for ALD and CVD applications, there may be non-uniformities originating from standing wave effects.

[0004] This standing wave effect may lead to high plasma uniformity at the center, thus affecting the uniformity of deposited films across the wafer.

[0005] To improve this non-uniformity, various solutions have been proposed. However, previous solutions may not be easy to implement in a CCP environment.

[0006] Therefore, the present disclosure proposes a wafer processing apparatus having an auxiliary ground path for improving non-uniformity. Summary of the invention

[0007] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the detailed description of the example embodiments disclosed below. This summary is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0008] According to one embodiment, a wafer processing device may be provided, comprising: a radio frequency (RF) housing enclosing and defining a reaction chamber; a showerhead arranged in the reaction chamber and configured to generate plasma for processing a wafer in the reaction chamber; a radio frequency (RF) power supply configured to generate RF and supply the generated RF to the showerhead; a plurality of capacitors connected in parallel and / or in series between the RF power supply and the showerhead; and one or more auxiliary ground lines configured to be placed above the showerhead.

[0009] According to another embodiment, one or more switches are provided, which are respectively coupled to each of the one or more auxiliary ground lines and are configured to allow current to flow through or not flow through the auxiliary ground lines.

[0010] In at least one aspect, the gap between the auxiliary ground line and the showerhead is between 2 mm and 15 mm.

[0011] In at least one aspect, the radius of the auxiliary ground line is between 2 mm and 10 mm.

[0012] In at least one aspect, the number of auxiliary ground lines is between 3 and 10, and the auxiliary ground lines are placed at equal angles around the showerhead.

[0013] In at least one aspect, one or more switches coupled to one or more auxiliary ground lines are configured to be turned on sequentially.

[0014] According to another embodiment, a wafer processing device may be provided, comprising: a radio frequency (RF) housing enclosing and defining a reaction chamber; a showerhead placed in the reaction chamber, configured to generate plasma for processing a wafer in the reaction chamber; a radio frequency (RF) power supply, configured to generate RF and supply the generated RF to the showerhead; a plurality of capacitors connected in parallel and / or in series between the RF power supply and the showerhead; one or more auxiliary ground lines configured to be placed above the showerhead; and one or more switches respectively coupled to each of the one or more auxiliary ground lines and configured to allow current to flow through or not flow through the auxiliary ground lines, wherein the one or more switches coupled to the one or more auxiliary ground lines are configured to be turned on sequentially to allow current to flow through or not flow through the auxiliary ground lines.

[0015] In at least one aspect, the gap between the auxiliary ground line and the showerhead is between 2 mm and 15 mm.

[0016] In at least one aspect, the radius of the auxiliary ground line is between 2 mm and 10 mm.

[0017] In at least one aspect, the number of auxiliary ground lines is between 3 and 10, and the auxiliary ground lines are placed at equal angles around the showerhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure.

[0019] Figure 1 A wafer processing device having an auxiliary ground path (line) according to an embodiment of the present disclosure is shown.

[0020] 2( a ) shows a top view of three auxiliary grounding paths located at 120° above the shower head according to an embodiment of the present disclosure, and FIG. 2( b ) shows a top view of four auxiliary grounding paths located at 90° above the shower head according to another embodiment of the present disclosure.

[0021] Figure 3 A side perspective view of the disclosed auxiliary ground path located directly above a showerhead according to an embodiment of the disclosed invention is shown.

[0022] Figure 4 A top view showing the location of the disclosed auxiliary ground path relative to the showerhead in which it is located and how far it is from the showerhead according to an embodiment of the present disclosure.

[0023] FIG. 5( a) shows a deflection graph profile from an auxiliary ground path at 0° according to an embodiment of the present disclosure, FIG. 5( b) shows a deflection graph profile from an auxiliary ground path at 120° according to an embodiment of the present disclosure, FIG. 5( c) shows a deflection graph profile from an auxiliary ground path at 240° according to an embodiment of the present disclosure, and FIG. 5( d) shows a deflection graph profile from an auxiliary ground path at 120° according to an embodiment of the present disclosure. Figure 5(a) to Figure 5(c) The averaged plot profiles were combined and averaged. DETAILED DESCRIPTION

[0024] Although certain embodiments and examples are disclosed below, those skilled in the art will appreciate that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specifically disclosed embodiments described below.

[0025] As used herein, the term "substrate" may refer to any one or more underlying materials, including any one or more underlying materials that may be modified or on which a device, circuit, or film may be formed. A "substrate" may be continuous or non-continuous; rigid or flexible; solid or porous; and combinations thereof. A substrate may be in any form, such as a powder, a plate, or a workpiece. A plate-like substrate may include wafers of various shapes and sizes. A substrate may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0026] For example, a substrate in powder form may have applications in pharmaceutical manufacturing. A porous substrate may comprise a polymer. Examples of workpieces may include medical devices (e.g., stents and syringes), jewelry, tooling equipment, components for battery manufacturing (e.g., anodes, cathodes, or separators), or components for photovoltaic cells, etc.

[0027] The continuous substrate may extend beyond the boundaries of the processing chamber in which the deposition process occurs. In some processes, the continuous substrate may be moved through the processing chamber so that the process continues until the end of the substrate is reached. The continuous substrate may be provided from a continuous substrate feed system to allow the continuous substrate to be manufactured and output in any suitable form.

[0028] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, meshes, flexible materials, bundles of continuous filaments or fibers (eg, ceramic fibers or polymer fibers). A continuous substrate may also include a carrier or sheet on which a discontinuous substrate is mounted.

[0029] The illustrations presented herein are not meant to be actual views of any particular material, structure, or device but are merely idealized representations used to describe embodiments of the present disclosure.

[0030] The specific embodiments shown and described are illustrations of the present invention and its best mode and are not intended to limit the scope of these aspects and embodiments in any way. In fact, for the sake of brevity, the traditional manufacturing, connection, preparation and other functional aspects of the system may not be described in detail. In addition, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in actual systems, and / or may not exist in some embodiments.

[0031] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific embodiments or examples should not be considered restrictive, because many variations are possible. The specific routine or method described herein can represent one or more of any number of processing strategies. Therefore, the various actions shown can be performed in the order shown, in other orders, or omitted in some cases.

[0032] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts and / or properties disclosed herein, and any and all equivalents thereof.

[0033] Figure 1 The entire wafer processing apparatus 100 with an auxiliary ground path (line) according to an embodiment of the present disclosure is shown.

[0034] The apparatus 100 includes an RF power supply 170 , an RF housing 120 enclosing and defining a reaction chamber, a showerhead (electrode) 110 , a parallel capacitor 140 and a series capacitor 150 , and an auxiliary ground path (or line) 130 .

[0035] The RF power source 170 generates RF power and supplies it to the showerhead 110. A line 145 connects the RF power source 170 and the showerhead 110.

[0036] The parallel capacitor 140 and the series capacitor 150 are connected in line 145 from the RF power source 170 to the showerhead 110 .

[0037] The capacitors 140, 150 may be connected in different ways (and in different quantities) to control the impedance of the line 145. The showerhead 110 will generate a plasma 160 for wafer processing.

[0038] An auxiliary ground path (AGP) 130 is installed below the upper RF housing 120 and above the showerhead 110. The auxiliary ground path is also referred to as an auxiliary ground line.

[0039] Without the AGP 130, the wafer profile would be primarily affected only by the plasma generation capabilities of the showerhead, and this would result in a profile that is thickest in the center (of the wafer being processed) and decreases in thickness outwards.

[0040] However, in the presence of AGP 130, the profiles (of the wafer) are changed due to the electric field generated by AGP 130. These profiles will be explained with reference to FIG.

[0041] 2(a) and 2(b) show top views of a device having multiple auxiliary ground paths.

[0042] FIG2(a) is 3, and FIG2(b) is 4. The AGP may be placed above the showerhead. To control the profile, current may flow through an auxiliary ground path (or line) 130. An electric field is generated from the AGP 130.

[0043] Observe the RF housing 210 and the showerhead 220, and in FIG. 2(a), three (3) AGPs 230, 231, 232 are placed at an angle of 120 degrees.

[0044] In FIG. 2( b ), four (4) AGPs 240 , 241 , 242 , 243 are placed above the showerhead 220 at 90 degrees.

[0045] As shown in Figure 2(a) and Figure 2(b), the number of AGPs can vary between 3 and 10 depending on the graph contour.

[0046] Figure 3 A side view of the present disclosure is shown.

[0047] The showerhead 300 is placed in a reaction chamber defined by the RF housing 320. In addition, an auxiliary ground line (or auxiliary ground path) 310 is placed just above the showerhead 300, and a switch 330 may be connected to the AGP 310 and may control whether current flows through the AGP 310.

[0048] When switch 330 is turned on and current flows through AGP 310 , the electric field generated by AGP 310 will be asymmetric due to the position of AGP 310 .

[0049] This asymmetry will be explained below using FIG. 5 .

[0050] Figure 4 A top view showing the location of an auxiliary ground path of the present disclosure relative to the showerhead in which it is located and how far it is from the showerhead according to an embodiment of the present disclosure.

[0051] The showerhead 400 may be placed at the center of the xy coordinates.

[0052] The xy coordinates may be imaginary and used to measure how far the AGP 410 is from its center (and showerhead 400).

[0053] Typically, the x-coordinate of the AGP 410 is between 30 mm and 150 mm, and the gap (d) between the AGP 410 and the showerhead 400 is between 2 mm and 15 mm.

[0054] The thickness (or radius r) of the auxiliary ground path 410 is between 2 mm and 10 mm, depending on the requirement of the electric field strength it generates.

[0055] Figure 5(a) to Figure 5(d) The deflection plot profiles from the auxiliary ground path at 0°, the deflection plot profiles from the auxiliary ground path at 120°, the deflection plot profiles from the auxiliary ground path at 240°, and the deflection plot profiles from the auxiliary ground path at 120° are shown. Figure 5(a) to Figure 5(c) The averaged plot profiles were combined and averaged.

[0056] When the AGP placed at 0 degrees is turned on (and the others are turned off), the profile will look like Figure 5(a) due to the strong electric field (E field) generated from the 0 degree AGP. In addition, when the AGP placed at 120 degrees is turned on (and the others are turned off), the profile will look like Figure 5(b) due to the electric field it generates.

[0057] An AGP placed at 240 degrees will produce the profile shown in Figure 5(c) due to the electric field it produces when the others may be turned off.

[0058] Finally, when controlling the switching sequence (duration, frequency, and on-time sequence of each AGP), the averaged graph profile appears rotationally symmetric as shown in Figure 5(d).

[0059] The non-uniformity of FIG5(d) is 8%, while the original non-uniformity is 18%.

[0060] The arrangement of the above method is only an illustration of the application of the principles of the present invention, and many other embodiments and modifications may be made without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the scope of the present invention should not be determined with reference to the above description, but with reference to the full scope of the appended claims and their equivalents.

Claims

1. A wafer processing device comprising: a radio frequency (RF) enclosure enclosing and defining the reaction chamber; a showerhead disposed within the reaction chamber and configured to generate a plasma for processing a wafer within the reaction chamber; a radio frequency (RF) power source configured to generate RF and supply the generated RF to the showerhead; a plurality of capacitors connected in parallel and / or series between the RF power source and the showerhead; and One or more auxiliary grounding lines are configured to be placed above the sprinkler head.

2. The wafer processing apparatus according to claim 1, further comprising: One or more switches are respectively coupled to each of the one or more auxiliary ground lines and are configured to allow current to flow through or not flow through the auxiliary ground lines.

3. The wafer processing apparatus according to claim 1, wherein: The gap between the auxiliary grounding line and the sprinkler head is between 2 mm and 15 mm.

4. The wafer processing apparatus according to claim 1, wherein: The radius of the auxiliary grounding line is between 2 mm and 10 mm.

5. The wafer processing equipment according to any one of claims 1 to 2, wherein: The number of the auxiliary grounding lines is between 3 and 10, and the auxiliary grounding lines are placed around the shower head at equal angles.

6. The wafer processing apparatus according to claim 5, wherein: The one or more switches coupled to the one or more auxiliary ground lines are configured to be turned on sequentially.

7. A wafer processing device comprising: a radio frequency (RF) enclosure enclosing and defining the reaction chamber; a showerhead disposed within the reaction chamber and configured to generate a plasma for processing a wafer within the reaction chamber; a radio frequency (RF) power source configured to generate RF and supply the generated RF to the showerhead; a plurality of capacitors connected in parallel and / or series between the RF power source and the showerhead; One or more auxiliary grounding circuits configured to be placed above the sprinkler heads; as well as one or more switches, respectively coupled to each of the one or more auxiliary ground lines and configured to allow current to flow through or not flow through the auxiliary ground lines, Wherein, one or more switches coupled to one or more auxiliary grounding lines are configured to be turned on sequentially to allow current to flow through or not flow through the auxiliary grounding lines.

8. The wafer processing apparatus according to claim 7, wherein: The gap between the auxiliary grounding line and the sprinkler head is between 2 mm and 15 mm.

9. The wafer processing apparatus according to claim 7, wherein: The radius of the auxiliary grounding line is between 2 mm and 10 mm.

10. The wafer processing apparatus according to claim 7, wherein: The number of the auxiliary grounding lines is between 3 and 10, and the auxiliary grounding lines are placed around the shower head at equal angles.

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