# Patent

## Title
Dual zone temperature control of upper electrodes

## Abstract

A system and method of plasma processing includes a plasma chamber including a substrate support and an upper electrode opposite the substrate support, the upper electrode having a plurality of concentric temperature control zones and a controller coupled to the plasma chamber.

## Background
CLAIM OF PRIORITY
This application claims priority from U.S. Provisional Patent Application No. 61/563,509 filed on Nov. 23, 2011 and entitled “Dual Zone Temperature Control of Upper Electrodes,” which is incorporated herein by reference in its entirety for all purposes.
RELATED APPLICATIONS
This application is related to U.S. patent application Ser. No. 13/301,725, filed Nov. 21, 2011, entitled “Triode Reactor Design With Multiple Radiofrequency Powers,” and U.S. Provisional Patent Application No. 61/563,021, filed Nov. 22, 2011, entitled “Systems And Methods For Controlling A Plasma Edge Region,” the disclosures of which are incorporated herein in their entirety by reference for all purposes. This application is also related to U.S. Provisional Patent Application No. 61/563,510, filed Nov. 23, 2011, entitled “Multi Zone Gas Injection Upper Electrode System” which is incorporated by reference herein in its entirety and for all purposes.


BACKGROUND
The present invention relates generally to plasma processing methods and systems and more particularly, to methods and systems for having dual temperature zones on an upper electrode in a plasma chamber.
FIG. 1A is side view a typical plasma chamber 100. The typical plasma chamber 100 has a single showerhead type upper electrode 102, a substrate support 140 for supporting a substrate 130 as the substrate is being processed by a plasma 150.
FIG. 1B is a more detailed view of a typical upper electrode in the plasma chamber 100. Typically, the showerhead type upper electrode 102 includes several layers 104, 110, 120, 125. A surface layer 104 includes an exposed plasma surface 104A and multiple outlet ports 106. The exposed plasma surface 104A is the surface of the surface layer that is exposed to the plasma 150. The outlet ports are substantially evenly distributed across the plasma chamber 100 so as to maintain a uniform distribution of the process gases.
Behind the surface layer 104, is a gas distribution layer 110. The gas distribution layer 110 includes multiple gas passages 112, 114 to distribute the process gases evenly to the ports 106 across the surface layer 104. The multiple gas passages 112, 114 are coupled to one or more external process gas sources, not shown. A great amount of effort is placed in detail in the design of the multiple gas passages 112, 114 so to ensure that the multiple gas passages evenly distribute the process gases to each of the outlet ports 106 and therefore evenly throughout the plasma chamber 100.
Behind the gas distribution layer 110 is a temperature control layer 120. The temperature control layer 120 includes elements 122. Elements 122 can heat or cool the temperature control layer 120, as desired, to control the temperature of the upper electrode 102. The temperature of the upper electrode 102 is controlled as one aspect of controlling the plasma processing occurring in the plasma chamber 100. A great amount of effort is placed in the detailed design of the temperature control layer 120 so as to maintain a uniform temperature across the surface layer 104.
Unfortunately, for various reasons, the plasma processing is not always uniform across the center to edge of the substrate 130. In view of the foregoing, what is needed is a system and method of manipulating the plasma processing from the center to the edge along of the substrate 130.
SUMMARY
Broadly speaking, the present invention fills these needs by providing a system and method of manipulating the plasma processing along the center to edge of the substrate. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, computer readable media, or a device. Several inventive embodiments of the present invention are described below.
One embodiment provides a system for plasma processing including a plasma chamber including a substrate support and an upper electrode opposite the substrate support, the upper electrode having multiple, concentric temperature control zones and a controller coupled to the plasma chamber.
The substrate support can include an edge ring proximate to an outer perimeter of a supported substrate. The edge ring can include a temperature control mechanism capable of heating or cooling the edge ring to a selected edge ring temperature. At least one of the concentric temperature control zones extends outside a radius of the edge ring.
Each one of the concentric temperature control zones can include a temperature control mechanism. The temperature control mechanism is capable of heating or cooling a respective one of the concentric temperature control zones to a corresponding selected temperature control zone temperature.
The substrate support can be capable of heating or cooling a supported substrate to a selected substrate temperature. The plasma chamber can also include a plasma confinement structure. The plasma confinement structure extends outside a radius of the substrate support.
The plasma processing system can also include an RF source coupled to the inner upper electrode. The RF source coupled to the inner upper electrode can be capable of heating the inner upper electrode.
Another embodiment provides a plasma processing system including a plasma chamber and a controller coupled the plasma chamber. The plasma chamber including a substrate support including an edge ring proximate to an outer perimeter of a supported substrate. The edge ring includes a temperature control mechanism capable of heating or cooling the edge ring to a selected edge ring temperature. An upper electrode is opposite the substrate support. The upper electrode includes multiple, concentric temperature control zones. At least one of the concentric temperature control zones extends outside a radius of the edge ring. A plasma confinement structure is also included in the plasma chamber. The plasma confinement structure extends outside a radius of the substrate support.
Yet another embodiment provides a method of selecting an edge etch rate using a dual temperature zone upper electrode. The method includes creating a plasma in a plasma chamber, reducing an edge etch rate including increasing an inner upper electrode temperature to a temperature greater than an outer upper electrode temperature and increasing an edge etch rate including decreasing an inner upper electrode temperature to a temperature less than an outer upper electrode temperature.
The outer upper electrode temperature can be in a plasma confinement structure. The plasma confinement structure extends outside a radius of a substrate support in the plasma chamber.
The inner upper electrode temperature can be opposite a substrate support in the plasma chamber. Reducing the edge etch rate can further include increasing a substrate temperature to a temperature greater than an outer upper electrode temperature. Increasing an edge etch rate can further include decreasing an inner upper electrode temperature to a temperature less than an edge ring temperature, the edge ring proximate to an outer perimeter of a substrate support in the plasma chamber.
Increasing the inner upper electrode temperature can include applying an RF signal to the inner upper electrode. Applying the RF signal to the inner upper electrode can include cooling the inner upper electrode.
Heating the inner upper electrode can include maintaining the inner upper electrode at a set point temperature including applying the RF signal to the inner upper electrode during a first period and simultaneously cooling the inner upper electrode during the first period and stopping applying the RF signal to the inner upper electrode during a second period and simultaneously heating the inner upper electrode during the second period.
Heating the inner upper electrode can include maintaining the inner upper electrode at a set point temperature including applying the RF signal to the inner upper electrode during a first period and simultaneously heating the outer upper electrode during the first period and stopping applying the RF signal to the inner upper electrode during a second period and simultaneously cooling the outer upper electrode during the second period.
Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.



BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings.
FIG. 1A is side view a typical plasma chamber.
FIG. 1B is a more detailed view of a typical upper electrode in the plasma chamber.
FIG. 2 is a plasma chamber, in accordance with embodiments of the present invention.
FIG. 3A is a schematic diagram of the edge region of the plasma chamber in accordance with embodiments of the present invention.
FIG. 3B is a graph of the density of the ions and neutrals, in accordance with embodiments of the present invention.
FIG. 3C is a graph of the relative etch rates across the radius of the substrate, in accordance with embodiments of the present invention.
FIG. 3D is a schematic diagram of a portion of the plasma chamber top, in accordance with embodiments of the present invention.
FIG. 4A is a flowchart diagram that illustrates the method operations performed in selecting an edge etch rate using a dual temperature zone upper electrode, in accordance with embodiments of the present invention.
FIG. 4B is a flowchart diagram that illustrates the method operations performed in maintaining a set point temperature of the upper electrode, in accordance with embodiments of the present invention.
FIGS. 5A and 5B are schematic diagrams of multi zone gas injection upper electrode, in accordance with embodiments of the present invention.
FIG. 5C is a graph of the effectiveness of tuning gas injections in each of the gas injection zones, in accordance with embodiments of the present invention.
FIGS. 5D and 5E are graphs of the relative densities of the tuning gas and the process gas, in accordance with an embodiment of the present invention.
FIG. 6 is a cross-sectional view of a plasma chamber having the multi zone gas injection upper electrode, in accordance with embodiments of the present invention.
FIG. 7A is a schematic diagram of a distributed gas supply feed, in accordance with embodiments of the present invention.
FIGS. 7B-F are schematic diagrams of plasma arrestors, in accordance with embodiments of the present invention.
FIG. 8 is a flowchart diagram that illustrates the method operations performed in selecting an edge etch rate using distributed gas zones, in accordance with embodiments of the present invention.
FIG. 9 is a simplified schematic diagram of a computer system in accordance with embodiments of the present invention.
FIG. 10A is a schematic diagram of the heated edge ring, in accordance with embodiments of the present invention.
FIGS. 10B and 10C are schematic diagrams of a cam lock, in accordance with embodiments of the present invention.
FIGS. 10D and 10E are schematic diagrams of electrical connections to the heaters, in accordance with embodiments of the present invention.
FIG. 10F is a schematic diagram of an optical temperature sensor, in accordance with embodiments of the present invention.



DETAILED DESCRIPTION
Several exemplary embodiments for system and method of manipulating the plasma processing along the center to edge of the substrate will now be described. It will be apparent to those skilled in the art that the present invention may be practiced without some or all of the specific details set forth herein.
One approach to manipulating the plasma processing along the center to edge of the substrate 130 is to vary the temperature of the upper electrode from the center 130A to edge 130B of the substrate. Another approach to manipulating the plasma processing from the center to edge of the substrate 130 is to manipulate the process gas concentrations along the center 130A to edge 130B of the substrate.
FIG. 2 is a plasma chamber 200, in accordance with embodiments of the present invention. The chamber of FIG. 2 includes RF power sources 220, 222, and 224 with RF frequencies f1, f2, f3, respectively, which are connected to the bottom electrode 108 via the corresponding matching networks. The upper electrode 201 is connected to a fourth RF power source 242, having an RF frequency f4, via switch 244 and matching network 246.
Further, the chamber includes a switch 244 that connects the upper electrode 201 to either ground potential or to RF power source 242 via matching network 246. A first heater 218 is situated above the upper electrode 201, and a second heater 216 is situated above ground electrode 248. The heaters are isolated from the upper electrode 201 and the ground electrode by a layer of aluminum nitride material, although other insulators may also be utilized. Heater 216 controls the temperature in the outer area of the ground electrode, and heater 218 controls the temperature of the upper electrode 201. Each heater is operable to be turned on or turned off independently during a substrate processing operation.
Controlling the temperature of the upper electrode may be utilized to adjust the response of the chamber. However, controlling the temperature has the limitation that the temperature cannot be changed quickly. Therefore, temperature control provides a slow response to changes in the chamber. It is difficult to control each substrate-processing operation utilizing temperature control of the upper electrode 201. In addition, there is an upper limit to the temperature that can be applied to the silicon surfaces in the chamber 200.
The wafer processing apparatus further includes system controller 202, upper electrode power controller 206, heater controller 208, and power controllers 210, 212, and 214 for f1, f2, and f3, respectively. System controller 202 receives a plasma recipe 204, which includes instructions for the different operations performed on the chamber. Processing of the wafer may be done in multiple operations, and each operation may require different settings in the chamber. For example, in one operation all four RF power sources are turned on, while in other operations only 3, or 2, or 1 RF power sources are turned on, etc.
Based on the recipe 204, the system controller sets the operational parameters of the chamber, including which RF power sources are turned on or turned off, their voltages and power settings, the setting of switch 244, the settings for heaters degrees 216 and 218, the gasses used in the chamber, the pressure on the chamber, the duration of the wafer-processing operation, etc. In one embodiment, the system controller 202 sends instructions to upper electrode power controller 206 for the configuration of the power on the top electrode, which includes setting switch 244 to connect the top electrode to ground or to RF power, and turning on or off RF power 242, as well as setting the power level for RF power 242.
System controller 202 interfaces with heater controller 208 to regulate the temperature of the upper electrode 201. Heater controller 208 regulates heaters 216 and 218 to control the temperature of the upper electrode 201. A temperature sensor (not shown) provides information to heater controller 208 on the temperature of the upper electrode 201 in one or more points of the upper electrode. Therefore, heater controller 208 may regulate the temperature on the upper electrode 201 by turning on or off the heaters to achieve a desired temperature during wafer processing.
System controller also 202 interfaces with power controllers 210, 212, and 214, which regulate whether the corresponding RF power 210, 222, or 224, is turned on or off, and if the power is turned on, to what power setting. In one embodiment, the frequency of RF power source 242 is 400 kHz. In another embodiment, the frequency is in the range from 400 kHz to 2 MHz, while in yet another embodiment the frequency is in the range from 100 kHz to 10 MHz. In some operations, the three bottom RF powers are not turned on simultaneously, which allows having a higher frequency at the top RF. In one embodiment, f4 is different from the frequencies at the bottom f1-f3 in order to avoid resonance on the chamber.
In one embodiment, the pressure in the chamber has a value between 20 mTorr and 60 mTorr. In another embodiment, the voltage of the top power source can be in the range of hundreds of volts (e.g., 100 V to 2000 V or more), and the bottom RF power sources can have a voltage up to 6000 V or more. In one embodiment, the voltage is 1000 V. In another embodiment, the voltage of the top RF power source has a value between 100 V and 600 V, and the voltage of the bottom RF power sources has a value between 1000 V and 6000 V. The pressure in the top chamber and the bottom chamber can have a value between 10 mTorr and 500 mTorr. In one embodiment, the chamber operates at a pressure of 15 mTorr.
It is noted that the embodiment illustrated in FIG. 2 is exemplary. Other embodiments may utilize different types of chambers, different frequencies, other types of adjustments for the chamber configuration based on the recipe, different pressures in the chamber, etc. For example, in one embodiment, the chamber is a CCP plasma chamber. Furthermore, some of the modules described above in the semiconductor wafer processing apparatus may be combined into a single module, or the functionality of a single module may be performed by a plurality of modules. For example, in one embodiment, power controllers 210, 212, and 214 are integrated within system controller 202, although other configurations are also possible. The embodiment illustrated in FIG. 2 should therefore not be interpreted to be exclusive or limiting, but rather exemplary or illustrative.
Dual Temperature Zone Upper Electrode
FIG. 3A is a schematic diagram of the edge region of the plasma 200 chamber in accordance with embodiments of the present invention. The upper electrode 201 is thermally coupled to an inner heater 218 over regions 312A over the substrate edge region 130B. A plasma confinement structure 252 extends outward beyond the substrate edge region 130B. The confinement structure 252 includes multiple confinement rings 254.
The substrate support 140 includes a 205. The heater 205 includes an edge ring temperature control mechanism capable of heating or cooling the edge ring to a desired edge ring temperature. The heater 205 is adjacent to and outside the substrate edge region 130B. The heater 205 is electrically isolated from the plasma by an edge ring 307.
The confinement structure 252 also includes a protrusion 310 that protrudes downward from the upper portion of the plasma chamber. The protrusion 310 is thermally coupled to an outer heater 216.
An insulator 250 electrically and thermally insulates the upper electrode 201 from the protrusion 310 and the inner heater 218 from the outer heater 216. The inner heater 218 can heat the upper electrode 201 to a first desired temperature T1 (i.e., an inner electrode temperature). The outer heater 216 can heat the protrusion 310 to a second desired temperature T2 (i.e., an outer electrode temperature) Similarly, the heater 205 can be heated to a third desired temperature T3 (i.e., an edge ring temperature). The substrate 130 can be heated to a fourth desired temperature T4 (i.e., a substrate temperature).
Densities of neutral molecules 302 and ions 304 in inner region 312A and outer region 312B can be selected by the relative temperatures T1, T2, T3 and T4. The neutral molecules 302 tend to buffer the reactivity between the etched surface and the ions 304. The neutral molecules 302 tend to diffuse in the thermal gradient and attach to the coldest surface of the relative temperatures T1, T2, T3 and T4. The relative densities of neutral molecules 302 and ions 304 can manipulated be to select etch rate.
By way of example, if T1>T2, then the relative density of the neutral molecules 302 can be increased in the inner plasma region 312A over the edge 130B of the substrate 130 as compared to outer plasma region 312B. Thus decreasing the reactivity of the ions 304 over the edge 130B of the substrate 130. This decreased reactivity of the ions 304 results in a correspondingly reduced etch rate of the edge region 130B of the substrate 130.
Similarly, if T2>T1, then the relative density of the neutral molecules 302 can be decreased in the inner plasma region 312A over the edge 130B of the substrate 130 as compared to outer plasma region 312B. Thus increasing the reactivity of the ions 304 over the edge 130B of the substrate 130. This increased reactivity of the ions 304 results in a correspondingly increased etch rate of the edge region 130B of the substrate 130.
By thus selecting the relative temperatures in the respective plasma regions 312A, 312B, the corresponding etch rate can be increased or decreased at the edge region 130B of the substrate 130.
FIG. 3B is a graph 350 of the density of the ions 304 and neutrals 302, in accordance with embodiments of the present invention. The graph 350 has the radius of the substrate on the horizontal axis and the relative density of the ions 304 and neutrals 302 is shown on the vertical axis.
FIG. 3C is a graph 370 of the relative etch rates across the radius of the substrate 130, in accordance with embodiments of the present invention. The graph 370 has the radius of the substrate on the horizontal axis and the etch rate is shown on the vertical axis of multiple etch iterations.
In the center region 130A of the substrate 130, the relative densities of the ions 304 and neutrals 302 are proximately equal and the corresponding etch rate is approximately equal in that same portion of the substrate.
Toward the edge region 130B of the substrate 130, the relative densities tend to vary at a drop-off line 352. Manipulating the relative temperatures T1, T2, T3, as described above, can move the drop-off line 352 left or right on the graph. Ideally, manipulating the relative temperatures T1, T2, T3, as described above, can move the drop-off line 352 to the right beyond the edge 130B of the substrate 130.
FIG. 3D is a schematic diagram of a portion of the plasma chamber top, in accordance with embodiments of the present invention. The inner heater 218, outer heater 216, ground electrode 248, gas distribution plate 610 and in insulator plate 382 (i.e., aluminum nitride or other suitable insulator). The gas distribution plate 610 can have an RF signal applied and thus typical thermo couples need filter networks to function effectively. Thus an optical temperature sensor 384 can be used to monitor the temperature of the gas distribution plate 610.
It should be understood that the optical temperature sensor 384 can be placed in any orientation and location that provides a suitable optical view of the gas distribution plate 610. The optical temperature sensor 384 can monitor the temperature of the gas distribution plate through the insulator plate 382. The ground electrode 248 can also include a plate heater.
The inner heater 218, the outer heater 216, the heated edge ring 307 by the heater 205 and the heating and cooling systems within the electrostatic chuck 140 can be used individually and in combination to reduce the thermal ramp up time in the plasma chamber. The inner heater 218, the outer heater 216, the heated edge ring 307 by the heater 205 and the heating and cooling systems within the electrostatic chuck 140 can also be used individually and in combination to minimize and even substantially eliminate interim, partial cooling that typically occurs during plasma processing in various portions of the plasma chamber. Reducing or eliminating interim, partial cooling improves the processing speed and maintains the plasma chamber at a more constant temperature over time and over the desired surfaces in the plasma chamber. Reducing or eliminating interim, partial cooling improves the consistency of the chemical processes as hot and cool spots and intervals can effect the partial pressures of the various gases and plasma by products present in the chamber.
FIG. 4A is a flowchart diagram that illustrates the method operations 400 performed in selecting an edge etch rate using a dual temperature zone upper electrode, in accordance with one embodiment of the present invention. The operations illustrated herein are by way of example, as it should be understood that some operations may have sub-operations and in other instances, certain operations described herein may not be included in the illustrated operations. With this in mind, the method and operations 400 will now be described.
In operation 405 a plasma 260 is created in the plasma chamber 262. In an operation 410 an inquiry is made to determine whether to reduce the etch rate over the edge region 130B. If the edge region 130B etch rate is to be reduced then the method operations continue in an operation 415. If the edge region 130B etch rate is not to be reduced then the method operations continue in an operation 420.
In operation 415 temperature T1 and/or T4 is adjusted to be greater than temperature T2 and T3, and the method operations continue in an operation 430.
In operation 420, an inquiry is made to determine whether to increase the etch rate over the edge region 130B. If the edge region 130B etch rate is to be increased then the method operations continue in operation 425. If the edge region 130B etch rate is not to be increased then the method operations continues in operation 430.
In operation 420 temperature T2 and/or T3 is adjusted to be greater than temperature T1 and T4, and the method operations continue in operation 430.
In operation 430, an inquiry is made to determine whether to the etch processing is complete. If the etch processing is complete then the method operations can end. If the etch processing is not complete then the method operations continue in operation 410 as described above.
Another aspect of having a dual zone temperature control of the upper electrode 201 is when the upper electrode has RF applied then heat will be generated in the upper electrode and then cool when the RF is not applied. The heaters 218, 216 provide dual zone temperature control the upper electrode 201 allows the central portion of the upper electrode 201 to be cooled when the RF is applied and heated the RF is not applied so as to maintain a desired set point temperature.
Another aspect of this invention is that the dual zone temperature control upper electrode can have the nonconductive surface 201A of the upper electrode 201 removable from the remainder of the electrode 201 for servicing (e.g., cleaning).
FIG. 4B is a flowchart diagram that illustrates the method operations 450 performed in maintaining a set point temperature of the upper electrode 201, in accordance with one embodiment of the present invention. The operations illustrated herein are by way of example, as it should be understood that some operations may have sub-operations and in other instances, certain operations described herein may not be included in the illustrated operations. With this in mind, the method and operations 450 will now be described.
In operation 452, a plasma 260 is created in the plasma chamber 262. In an operation 454 an inquiry is made to determine whether RF is applied to the upper electrode 201. If RF is applied to the upper electrode 201, then the method operations continue in an operation 456. If RF is not applied to the upper electrode 201, then the method operations continue in an operation 458.
In operation 456, temperature T1 is reduced to maintain a set point temperature and the method operations continue in an operation 460. In operation 458, temperature T1 is increased to maintain a set point temperature and the method operations continue in operation 460.
In operation 460, an inquiry is made to determine whether to the etch processing is complete. If the etch processing is complete then the method operations can end. If the etch processing is not complete then the method operations continue in operation 454 as described above.
Multi Zone Gas Injection Upper Electrode
Another approach to manipulate the etch rate from the center 130A to edge 130B of the substrate 130 is to adjust the process gas concentrations radially from the center to edge of the substrate. The multi zone gas injection from the upper electrode 501 allows a tuning gas (e.g., oxygen or other tuning gas) to be injected in different zones radially outward from the center of the substrate 130. The tuning gas changes the carbon/fluorine ratio at the surface of the substrate 130 and thus changes the ion density and the corresponding etch rate.
The exemplary embodiment described herein includes three gas injections zones in the upper electrode 501 however it should be understood that more than three zones could also be used (e.g., four or more zones).
FIGS. 5A and 5B are schematic diagrams 500, 550 of multi zone gas injection upper electrode 501, in accordance with embodiments of the present invention. The multi zone gas injection upper electrode 501 includes three gas injection zones 502, 504 and 506. A gas injection zones 502, 504 and 506 are concentric.
The central gas injection zone 1, 502 has a central gas supply feed 552. Each of the concentric gas injection zones 504, 506 has respective gas supply feeds that are substantially evenly distributed around the respective circumference. By way of example, gas injection zone 2 504 has four gas supply feeds 554 which are in turn supplied by a central and spoke distribution manifold. Similarly, gas injection zone 3 506 has eight gas supply feeds 556 which are in turn supplied by a central and spoke distribution manifold.
The evenly distributed gas supply feeds 554, 556 can be aligned in their respective gas injection zone 504, 506. Alternatively, the evenly distributed gas supply feeds 554, 556 can be offset (i.e., clocked) in their respective gas injections zone 504, 506. The number of distributed gas supply feeds 554, 556 can be the same in each zone 504, 506 or different numbers in each zone.
Each of the gas injection zones 502, 504, 506 can include one or more concentric gas plenum rings 562, 564, 566. The gas plenum rings 562, 564, 566 are coupled in together by multiple gas channels 572, 574, 576 within their respective gas injection zones 502, 504, 506. Each of the gas injection zones 502, 504, 506 include multiple outlet ports 532, 534, 536 through the surface of the upper electrode and into the plasma zone.
FIG. 5C is a graph 520 of the effectiveness of tuning gas injections in each of the gas injection zones 502, 504, 506, in accordance with embodiments of the present invention. Graph 521 is the effectiveness of the tuning gas injected in the gas injections zone1 502. Graph 522 is the effectiveness of the tuning gas injected in the gas injections zone2 504. Graph 523 is the effectiveness of the tuning gas injected in the gas injections zone3 506.
Referring to graph 521, the tuning gas injected in gas injection zone 1, 502 is more consistently effective (i.e., more linearly predictable) across gas injection zone 1 than in gas injection zone 2, 504 and zone 3 506. Referring to graph 522, the tuning gas injected in gas injection zone 2, 504 is more consistently effective across gas injection zone 2 than in gas injection zone 1, 502 or zone 3 506. Referring to graph 523, the tuning gas injected in gas injection zone 3, 506 is more consistently effective across gas injection zone 3 than in gas injection zone 1, 502 or zone 2 504.
FIGS. 5D and 5E are graphs 580, 590 of the relative densities of the tuning gas and the process gas, in accordance with an embodiment of the present invention. Increasing the tuning gas (oxygen) flow rate increases the presence of oxygen radicals proportionally to the flow rate. While the process gas (Fluorine) density is substantially constant. Increasing the process gas (C4F8) flow rate decreases the relative density of the oxygen radical. The process gas radical (Fluorine) increases substantially proportionally to the process gas flow rate. The relative density of the oxygen radical controls the degree of polymer removal without changing the plasma properties. The relative density of the process gas impacts the effectiveness at lower residence times.
FIG. 6 is a cross-sectional view of a plasma chamber 600 having the multi zone gas injection upper electrode 501, in accordance with embodiments of the present invention. The cross-sectional view of a plasma chamber 600 illustrates the multi layer assembly forming the top portion of the plasma chamber. The multi zone gas injection upper electrode 501 includes an inner electrode 201 and an outer electrode 310. Insulator 250 separates the inner electrode 201 and the outer electrode 310. Insulator 250 can be quartz or some other suitable insulating material. The inner electrode 201 and the outer electrode 310 can have different signals applied. By way of example an RF signal can be applied to the inner electrode 201 and a ground or other DC potential can be applied to the outer electrode 310.
The inner electrode 201 is removably mounted on a gas distribution plate 610. The gas distribution plate 610 distributes the process gases and tuning gases across the upper electrode 501. The gas distribution plate 610 includes distribution plenums 562, 564, 566 and channels 572, 574, 576 for evenly distributing the process gases and tuning gases.
The gas distribution plate 610 is mounted on an insulator plate 612. The insulator plate 612 electrically isolates the inner electrode 201 from the other layers forming the top portion of the plasma chamber 600. The gas feeds 552, 554, 556 can include plasma arrestors 620. The plasma arrestors 620 prevent plasma from lighting in the gas feeds 552, 554, 556.
FIG. 7A is a schematic diagram of a distributed gas supply feed, 554, 556, in accordance with embodiments of the present invention. One or more of distributed gas supply feeds 554, 556 can include a plasma arrestor 620.
FIGS. 7B-F are schematic diagrams of plasma arrestors 620, 620′, in accordance with embodiments of the present invention. The plasma arrestors 620, 620′ substantially prevents plasma from igniting inside the distributed gas supply feed, 554, 556. Seals 702A, 702B prevent gas leakage.
The plasma arrestor 620 can include multiple small tubes 750 and fluted channels 752 along the exterior portion of the plasma arrestor. The small tubes 750 and the fluted channels 752 have a width small enough that it extinguishes any plasma that reaches the plasma arrestor 620. The plasma arrestor 620 can also include a grounding electrode (not shown) that can assist in extinguishing any plasma that reaches the plasma arrestor.
An alternative plasma arrestor 620′ has a spiral outer coil 760 that forms a spiral channel having a width small enough that it extinguishes any plasma that reaches a plasma arrestor. The spiral outer coil 760 can also be grounded to assist in extinguishing the plasma that reaches the plasma arrestor 620′. The plasma arrestors 620, 620′ can be made from a ceramic material (e.g., alumina or similar).
FIG. 8 is a flowchart diagram that illustrates the method operations 800 performed in selecting an edge etch rate using distributed gas zones 502, 504, 506, in accordance with one embodiment of the present invention. The operations illustrated herein are by way of example, as it should be understood that some operations may have sub-operations and in other instances, certain operations described herein may not be included in the illustrated operations. With this in mind, the method and operations 800 will now be described.
In operation 802 a plasma 260 is created in the plasma chamber 262. In an operation 804 an inquiry is made to determine whether to reduce the etch rate over inner gas distribution zone 1, 502. If the inner gas distribution zone 1, 502 etch rate is to be reduced then the method operations continue in an operation 806. If the inner gas distribution zone 1, 502 etch rate is not to be reduced then the method operations continue in an operation 808.
In operation 806 tuning gas is injected into the inner gas distribution zone 1, 502, and the method operations continue in an operation 816.
In operation 808, an inquiry is made to determine whether to reduce the etch rate over mid gas distribution zone 2, 504. If the mid gas distribution zone 2, 504 etch rate is to be reduced then the method operations continue in an operation 810. If the mid gas distribution zone 2, 504 etch rate is not to be reduced then the method operations continue in an operation 812.
In operation 810 tuning gas is injected into the mid gas distribution zone 2, 504, and the method operations continue in an operation 816.
In operation 812, an inquiry is made to determine whether to reduce the etch rate over outer gas distribution zone 3, 506. If the outer gas distribution zone 3, 506 etch rate is to be reduced then the method operations continue in an operation 814. If the outer gas distribution zone 3, 506 etch rate is not to be reduced then the method operations continue in an operation 816.
In operation 812 tuning gas is injected into the outer gas distribution zone 3, 506, and the method operations continue in an operation 816.
In operation 816, an inquiry is made to determine whether to the etch processing is complete. If the etch processing is complete then the method operations can end. If the etch processing is not complete then the method operations continue in operation 804 as described above.
FIG. 9 is a simplified schematic diagram of a computer system 900 in accordance with embodiments of the present invention. It should be appreciated that the methods described herein may be performed with a digital processing system, such as a conventional, general-purpose computer system. Special purpose computers, which are designed or programmed to perform only one function, may be used in the alternative. The computer system includes a central processing unit (CPU) 904, which is coupled through bus 910 to random access memory (RAM) 928, read-only memory (ROM) 912, and mass storage device 914. Phase control program 908 resides in random access memory (RAM) 928, but can also reside in mass storage 914 or ROM 912.
Mass storage device 914 represents a persistent data storage device such as a floppy disc drive or a fixed disc drive, which may be local or remote. Network interface 930 provides connections via network 932, allowing communications with other devices. It should be appreciated that CPU 904 may be embodied in a general-purpose processor, a special purpose processor, or a specially programmed logic device. Input/Output (I/O) interface provides communication with different peripherals and is connected with CPU 904, RAM 928, ROM 912, and mass storage device 914, through bus 910. Sample peripherals include display 918, keyboard 922, cursor control 924, removable media device 934, etc.
Display 918 is configured to display the user interfaces described herein. Keyboard 922, cursor control 924, removable media device 934, and other peripherals are coupled to I/O interface 920 in order to communicate information in command selections to CPU 904. It should be appreciated that data to and from external devices may be communicated through I/O interface 920. The embodiments can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a wire-based or wireless network.
FIG. 10A is a schematic diagram of the heated edge ring 307, in accordance with embodiments of the present invention. A heater 205 can optionally be included to heat the edge ring 307.
FIGS. 10B and 10C are schematic diagrams of a cam lock 1010, in accordance with embodiments of the present invention. The cam lock 1010 includes a cam lock shaft 1011 and a cam lock head 1012. The cam lock 1010 couples with a latch 1014 to secure the electrostatic chuck 140 to the facilities plate 1015.
FIGS. 10D and 10E are schematic diagrams of electrical connections 1020, 1022 to the heaters 205, in accordance with embodiments of the present invention. The electrical connections 1020, 1022 couple electrical power to the heaters 205. The electrical connections 1020, 1022 are coupled to the heaters 205 when the cam locks 1010 secure the electrostatic chuck 140 to the facilities plate 1015.
FIG. 10F is a schematic diagram of an optical temperature sensor 1030, in accordance with embodiments of the present invention. The optical temperature sensor 1030 monitors the temperature of the edge ring 307 and couples this temperature data to the system controller.
With the above embodiments in mind, it should be understood that the invention may employ various computer-implemented operations involving data stored in computer systems. These operations are those requiring physical manipulation of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. Further, the manipulations performed are often referred to in terms, such as producing, identifying, determining, or comparing.
The invention can also be embodied as computer readable code and/or logic on a computer readable medium. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include hard drives, network attached storage (NAS), logic circuits, read-only memory, random-access memory, CD-ROMs, CD-Rs, CD-RWs, magnetic tapes, and other optical and non-optical data storage devices. The computer readable medium can also be distributed over a network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.
It will be further appreciated that the instructions represented by the operations in the above figures are not required to be performed in the order illustrated, and that all the processing represented by the operations may not be necessary to practice the invention. Further, the processes described in any of the above figures can also be implemented in software stored in any one of or combinations of the RAM, the ROM, or the hard disk drive.
Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

## Claims

1. A plasma processing system comprising:
a plasma chamber including:
a substrate support; and
an upper electrode opposite the substrate support, the upper electrode having a plurality of concentric temperature control zones;
an edge ring proximate to an outer perimeter of a supported substrate;
a temperature control mechanism including a pair of electrical connections for coupling electrical power to a heater, the heater is configured to receive the electrical power from the pair of electrical connections during operation, wherein the pair of electrical connections couple to the heater by way of a cam lock secured to the substrate support, the heater of the temperature control mechanism being disposed below and in thermal contact with edge ring for heating the edge ring to a selected edge ring temperature during processing; and
a controller coupled to the plasma chamber for setting the selected edge ring temperature.

2. The plasma processing system of claim 1, wherein at least one of the plurality of concentric temperature control zones extends outside a radius of the edge ring.

3. The plasma processing system of claim 1, wherein each one of the plurality of concentric temperature control zones includes a temperature control mechanism.

4. The plasma processing system of claim 3, wherein the temperature control mechanism is capable of heating or cooling a respective one of the plurality of concentric temperature control zones to a corresponding selected temperature control zone temperature.

5. The plasma processing system of claim 1, wherein the substrate support is capable of heating or cooling a supported substrate to a selected substrate temperature.

6. The plasma processing system of claim 1, wherein the plasma chamber further includes a plasma confinement structure, the plasma confinement structure extends outside a radius of the substrate support.

7. The plasma processing system of claim 1, further comprising an RF source coupled to inner upper electrode.

8. The plasma processing system of claim 7, wherein the RF source coupled to the inner upper electrode is capable of heating the inner upper electrode.

9. A plasma processing system comprising:
a plasma chamber including:
a substrate support includes an edge ring proximate to an outer perimeter of a supported substrate wherein the edge ring includes a temperature control mechanism capable of heating the edge ring to a selected edge ring temperature, wherein the temperature control mechanism includes a pair of electrical connections for coupling electrical power to a heater, the heater is configured to receive the electrical power from the pair of electrical connections during operation, wherein the pair of electrical connections couple to a bottom surface of the heater when a cam lock is secured to the substrate support, a top surface of the heater is disposed below the edge ring, the heater is configured to thermally transfer heat for heating the edge ring to the selected edge ring temperature during processing;
an upper electrode opposite the substrate support, the upper electrode having a plurality of concentric temperature control zones wherein at least one of the plurality of concentric temperature control zones extends outside a radius of the edge ring;
a plasma confinement structure, the plasma confinement structure extends outside a radius of the substrate support; and
a controller coupled to the plasma chamber.

10. A plasma processing system, comprising:
a plasma chamber, including:
a substrate support includes an edge ring proximate to an outer perimeter of a supported substrate, wherein the edge ring includes a temperature control mechanism for heating the edge ring to a selected temperature, wherein the temperature control mechanism includes a pair of electrical connections for coupling electrical power to a heater, the heater is configured to receive the electrical power from the pair of electrical connections during operation, wherein the pair of electrical connections couple to a bottom surface of the heater when a cam lock is secured to the substrate support, a top surface of the heater is disposed below the edge ring, the heater is configured as a ring that thermally transfers heat for heating the edge ring to the selected temperature during processing; and
an upper electrode opposite the substrate support, the upper electrode having an inner temperature control zone and an outer temperature control zone, wherein the outer temperature control zone outside a radius of the edge ring, the upper electrode further including an insulator that thermally and electrically insulates the inner temperature control zone from the outer temperature control zone;
a protrusion extending below the outer temperature control zone of the upper electrode, the protrusion disposed at least partially over the edge ring;
a plasma confinement structure, the plasma confinement structure disposed between the substrate support and the protrusion of the upper electrode; and
a controller coupled to the plasma chamber.