PULSED DC SPUTTERING SYSTEMS AND METHODS
20210027998 ยท 2021-01-28
Inventors
- Robert George Andosca, Ph.D. (Fort Collins, CO, US)
- Douglas R. Pelleymounter (Northfield, MN, US)
- David Christie (Fort Collins, CO, US)
Cpc classification
C23C14/086
CHEMISTRY; METALLURGY
International classification
Abstract
Systems and methods for are disclosed. One method includes providing at least a first electrode, a second electrode, and a third electrode and using each of at least two, separate and different, target materials in connection with the three electrodes to enable sputtering. The method also includes applying a first voltage at the first electrode that alternates between positive and negative relative to the second electrode during each of multiple cycles and applying a second voltage to the third electrode that alternates between positive and negative relative to the second electrode during each of the multiple cycles.
Claims
1. A pulsed sputtering system comprising: first electrode, a second electrode, and a third electrode; at least two, separate and different, target materials, each of the target materials coupled to a corresponding one of the electrodes; a first power source coupled to the first electrode and the second electrode, wherein the first power source is configured to apply a first voltage at the first electrode that alternates between positive and negative relative to the second electrode during each of multiple cycles; and a second power source coupled to the third electrode and the second electrode, the second power source is configured to apply a second voltage to the third electrode that alternates between positive and negative relative to the second electrode during each of the multiple cycles.
2. The pulsed sputtering system of claim 1, wherein the first electrode and the third electrode are each a part of a magnetron to form a first magnetron and a third magnetron wherein each of the first magnetron and the third magnetron is coupled to a corresponding one of the two separate and different target materials, and wherein the second electrode is neither coupled to a target nor a part of a magnetron to operate as an anode.
3. The pulsed sputtering system of claim 1, wherein each of the three electrodes is a part of a magnetron to form a first magnetron, a second magnetron, and a third magnetron, and wherein one of the at least two, separate and different, target materials is coupled to the first and third magnetron and another of the at least two, separate and different, target materials is coupled to the second magnetron.
4. The pulsed sputtering system of claim 1, wherein each of the three electrodes is a part of a magnetron to form a first magnetron, a second magnetron, and a third magnetron and the at least two, separate and different, target materials includes three separate and different target materials, wherein each of the three separate and different target materials is coupled to a corresponding one of the three magnetrons.
5. The pulsed sputtering system of claim 1, comprising a ground shield aperture and a movable platform to move a substrate in any direction to uniformly to deposit the at least two separate and different target materials on the substrate.
6. The pulsed sputtering system of claim 1, comprising a plasma chamber that encloses the first electrode, the second electrode, and the third electrode.
7. A method for sputtering comprising: providing at least a first electrode, a second electrode, and a third electrode; using each of at least two, separate and different, target materials in connection with one of the three electrodes; applying a first voltage at the first electrode that alternates between positive and negative relative to the second electrode during each of multiple cycles; and applying a second voltage to the third electrode that alternates between positive and negative relative to the second electrode during each of the multiple cycles.
8. The method of claim 7, comprising: phase-synchronizing the first voltage with the second voltage, so both, the first voltage and the second voltage are simultaneously negative during a portion of each cycle and simultaneously positive relative to the second electrode during another portion of each cycle.
9. The method of claim 8, wherein: the first electrode voltage and the third electrode voltage are simultaneously negative relative to the second electrode at least 70 percent of a time over the multiple cycles.
10. The method of claim 9, comprising: applying a greater level of power during a half cycle when the first electrode voltage and the third electrode voltage are simultaneously positive relative to the second electrode.
11. The method of claim 10, comprising: applying at least twice a level of power during a half cycle when the first electrode voltage and the third electrode voltage are simultaneously positive relative to the second electrode.
12. The method of claim 8, comprising: applying a greater level of power during a half cycle when the first electrode voltage and the third electrode voltage are simultaneously negative relative to the second electrode.
13. The method of claim 7, comprising: using each of at least three, separate and different, target materials in connection with the three electrodes.
14. The method of claim 7, comprising: phase-desynchronizing the first voltage with the second voltage, so there is a phase offset between the first voltage and the second voltage.
15. The method of claim 7, comprising: employing a horizontal ground shield aperture and moving a substrate in any direction to uniformly to deposit the at least two separate and different target materials on the substrate.
16. A pulsed sputtering system comprising: a first electrode, a second electrode, and a third electrode; at least two, separate and different, target materials, each of the target materials coupled to a corresponding one of the electrodes; means for applying a first voltage at the first electrode that alternates between positive and negative relative to the second electrode during each of multiple cycles; and means for applying a second voltage to the third electrode that alternates between positive and negative relative to the second electrode during each of the multiple cycles.
17. The pulsed sputtering system of claim 16 wherein each of the three electrodes is a part of a magnetron to form a first magnetron, a second magnetron, and a third magnetron, and wherein one of the at least two, separate and different, target materials is coupled to the first and third magnetron and another of the at least two, separate and different, target materials is coupled to the second magnetron.
18. The pulsed sputtering system of claim 16, wherein each of the three electrodes is a part of a magnetron to form a first magnetron, a second magnetron, and a third magnetron and the at least two, separate and different, target materials includes three separate and different target materials, wherein each of the three separate and different target materials is coupled to a corresponding one of the three magnetrons.
19. The pulsed sputtering system of claim 16, comprising a plasma chamber that encloses the first electrode, the second electrode, and the third electrode.
20. The pulsed sputtering system of claim 16, comprising phase-synchronizing the first voltage with the second voltage, so both, the first voltage and the second voltage are simultaneously negative during a portion of each cycle and simultaneously positive relative to the second electrode during another portion of each cycle.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
DETAILED DESCRIPTION
[0029] The word exemplary is used herein to mean serving as an example, instance, or illustration. Any embodiment described herein as exemplary is not necessarily to be construed as preferred or advantageous over other embodiments.
[0030] Referring to
[0031] Beneficially, many variations of the system 100 may cut the RMS current in the endblocks or magnetrons by about half as compared to prior AC sputtering systems. As a consequence, in cases in which the endblock current rating is limited, the system 100 may enable delivery of nearly twice the power while staying within the endblock current rating limit. Another aspect of the system depicted in
[0032] Additional aspects of the system 100 include a resultant reduction of heat load to the substrate, or a higher deposition rate at the same substrate heat load. Moreover, another aspect of many implementations is that substantially the same deposition rate (per total power (kW) delivered to the process) can be expected as compared to mid-frequency (MF) (AC or pulsed) dual magnetron sputtering. The system 100 may provide about 2 times the deposition rate of AC dual magnetron or bi-polar pulsed DC sputtering, with lower heat load experienced in typical sputtering systems. As discussed herein, the voltage in each cycle may reverse 100%. And beneficially, some implementations operate while producing undetectable anode material levels in a film on the substrate.
[0033] As shown in
[0034] In some implementations of
[0035] As shown, a controller 144 is coupled to the first power source 140 and the second power source 142 to control the power sources 140, 142. In some modes of operation, the controller 144 is configured to control the first power source 140 and the second power source 142 to phase-synchronize the first voltage VAB with the second voltage VCB, so both, the first voltage VAB and the second voltage VCB are simultaneously negative during a portion of each cycle and simultaneously positive relative to the anode during another portion of each cycle. In other modes of operation, the controller 144 is configured to control the first power source 140 and the second power source 142 to phase-desynchronize the first voltage VAB with the second voltage VCB, so there is a phase offset between the first voltage VAB and the second voltage VCB. In many variations of the implementation in
[0036] As shown, at least two electrodes are each used with a corresponding one of two different target materials (target material 1 and target material 2) so that the system 100 operates in a co-sputtering configuration. The materials utilized for target material 1 and target material 2 are different but may vary and may be used in different combinations. For example, the target materials may include, without limitation, aluminum, indium, tin, lead, zirconium, zinc, titanium. Although the target materials may be elemental materials, it is also contemplated that the target materials may include composite materials while each of the two magnetrons is used with a corresponding one of two different composite target materials. Exemplary combinations of target materials include indium coupled to one of the electrodes and tin coupled to the other electrode. Another combination (that may be used in 3-magnetron configurations discussed further herein) is lead, zirconium, titanium.
[0037] As described in more detail further herein, a plasma is generated in response to the application of a pulsed voltage within the chamber 101. As those of ordinary skill in the art will appreciate, gases are provided to the plasma chamber 101 and a plasma is ignited within the chamber 101. More specifically, there may be reactant gases and ion peening gases fed into the plasma chamber 101. The reactant gases may include, for example, nitrogen, oxygen, and the ion peening gas may be argon.
[0038] As depicted in
[0039] Referring to
[0040] To achieve the voltages in
[0041] As discussed further herein, each of the first and second power sources 140, 142 may include a bi-polar controllable pulsed DC power supply to apply the first voltage V.sub.AB and second voltage V.sub.CB. And as discussed in more detail further herein, the controller 144 may be realized by hardware, firmware or a combination of software and hardware and/or hardware and firmware. Moreover, arc management synchronization may be implemented so that a detected arc in the plasma prompts the power sources 140, 142 to stop applying power to the electrodes.
[0042] Referring next to
[0043] While referring to
[0044] Referring to
[0045] As shown in
[0046]
[0047] It should be recognized that three electrodes (E1, E2, and E3) are depicted in
[0048] Referring next to
[0049] In an exemplary mode of operation, the magnetrons M1, M3 share the same duty, which is referred to in
[0050] In operation, a power set point may be different for the second power source 142 that directly affects the power applied to the tin target as compared to the first power source 140 that directly affects the power applied to the indium target (to compensate for lower sputtering yield of tin as contrasted with indium), which results in a more stoichiometric ITO film. Using the depicted configuration may yield up to twice the deposition rate of using a standard co-sputtering dual magnetron sputtering configuration. And the yield from the system in
[0051] Although not required, a bias voltage can be applied to substrate holder to increase ion peening energy to densify the ITO film while enhancing other material properties at potentially lower substrate temperatures. In addition, the substrate may move back and forth under the horizontal ground shield aperture so the deposited ITO film thickness and materials properties are substantially uniform across the entire substrate.
[0052] Referring to
[0053] In both use cases depicted in
[0054] Referring next to
[0055] Referring next to
[0056] Of note, each of the first and second power sources 140, 142 may be arranged and configured to be aware of the other one of the first and second power sources 140, 142, without attempting to control the operation of the other one of the first and second power sources 140, 142. Applicant has achieved this awareness without control by first configuring a frequency (e.g. 40 kHz) and duty of each of the first and second bi-polar controllable pulsed DC supplies 112, 114, and subsequently coupling the synchronizing unit 120 and configuring one of the first and second bi-polar controllable pulsed DC supplies 112, 114 to be perceived as a transmitter for the purpose of frequency synchronization, and the other one of the first and second bi-polar controllable pulsed DC supplies 112, 114 to be perceived as a receiver, for the purpose of frequency synchronization. In contrast, each one of the first and second DC supplies 116, 118 may be independent, and do not rely on awareness of the other one of the first and second DC supplies 116, 118 to properly function.
[0057] Although not required, in one implementation, the first and second DC supplies 116, 118 may each be realized by one or more ASCENT direct current power supplies sold by Advanced Energy Industries, Inc. of Fort Collins, Colo., U.S.A. And the first and second bi-polar controllable pulsed DC supplies 112, 114 may each be realized by an ASCENT DMS Dual-magnetron sputtering accessory, which is also sold by Advanced Energy Industries, Inc. of Fort Collins, Colo., U.S.A. In this implementation, the first and second power sources 140, 142 are each realized as an AMS/DMS stack wherein the ASCENT direct current power supply may provide straight DC power, and the DMS dual-magnetron sputtering accessory generates a pulsed DC waveform from the straight DC power and performs arc management. Beneficially, the DMS dual-magnetron sputtering accessories may be located in close proximity to the chamber 101, and the ASCENT direct current power supplies may be located remotely (e.g., in a remote rack) from the chamber 101. The synchronizing unit 120 in this implementation may be realized by a common exciter (CEX) function of the DMS accessories. In another embodiment, each of the first and second power sources 140, 142 may be realized by an integrated pulsed DC power supply.
[0058] The methods (including the control methodologies) described in connection with the embodiments disclosed herein may be embodied directly in hardware, in processor executable instructions encoded in non-transitory processor readable medium, or in a combination of the two. Referring to
[0059] This display 2212 generally operates to provide a user interface for a user, and in several implementations, the display 2212 is realized by a touchscreen display. In general, the nonvolatile memory 2220 is non-transitory memory that functions to store (e.g., persistently store) data and processor executable code (including executable code that is associated with effectuating the methods described herein). In some embodiments for example, the nonvolatile memory 2220 includes bootloader code, operating system code, file system code, and non-transitory processor-executable code to facilitate the execution of the methods described herein.
[0060] In many implementations, the nonvolatile memory 2220 is realized by flash memory (e.g., NAND or ONENAND memory), but it is contemplated that other memory types may be utilized. Although it may be possible to execute the code from the nonvolatile memory 2220, the executable code in the nonvolatile memory is typically loaded into RAM 2224 and executed by one or more of the N processing components in the processing portion 2226.
[0061] The N processing components in connection with RAM 2224 generally operate to execute the instructions stored in nonvolatile memory 2220 to enable the power sources 140, 142 to achieve one or more objectives. For example, non-transitory processor-executable instructions to effectuate the methods described herein may be persistently stored in nonvolatile memory 2220 and executed by the N processing components in connection with RAM 2224. As one of ordinary skill in the art will appreciate, the processing portion 2226 may include a video processor, digital signal processor (DSP), graphics processing unit (GPU), and other processing components.
[0062] In addition, or in the alternative, the FPGA 2227 may be configured to effectuate one or more aspects of the methodologies described herein. For example, non-transitory FPGA-configuration-instructions may be persistently stored in nonvolatile memory 2220 and accessed by the FPGA 2227 (e.g., during boot up) to configure the FPGA 2227 to effectuate the functions of the controller 144.
[0063] The input component may operate to receive signals that are indicative of one or more aspects of the power applied to the electrodes (e.g., magnetrons and/or the anodes). The signals received at the input component may include, for example, voltage, current, and/or power. The output component generally operates to provide one or more analog or digital signals to effectuate an operational aspect of the first and/or second power sources 140, 142. For example, the output portion may be a signal to cause the first bi-polar controllable pulsed DC power supply 112 and/or second controllable pulsed DC power supply 114 to effectuate some of the methodologies described herein. In some embodiments, the output component may operate to adjust a voltage, frequency, and/or duty of the first and/or second power source 140, 142.
[0064] The depicted transceiver component 2228 includes N transceiver chains, which may be used for communicating with external devices via wireless or wireline networks. Each of the N transceiver chains may represent a transceiver associated with a particular communication scheme (e.g., WiFi, Ethernet, Profibus, etc.).
[0065] Referring briefly back to
[0066]
[0067] In contrast,
[0068] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.