Patent Application
20210287884
This disclosure relates to systems for workpiece processing. More particularly, this disclosure relates to workpiece processing with plasma.
Plasma processing systems are commonly used for modifying the surface properties of workpieces in various industrial applications. For example, plasma processing systems are routinely used to plasma treat the surfaces of integrated circuits, electronic packages, and printed circuit boards in semiconductor applications, solar panels, hydrogen fuel cell components, automotive components, and rectangular glass substrates used in flat panel displays.
Plasma treatment, however, presents a number of unique challenges. For example, heat generation remains a common problem, especially during those plasma treatments that require the workpiece to be held at high temperature during the treatment. Unchecked heat generation may produce a work environment in which operators are at risk of being burned unless the production facility undertakes expensive measures to address this risk, such as guards or barriers for the plasma treatment systems or devices. These safety measures also typically require additional floor space for each system or device. Excessive heat may also result in increased operational costs due to the additional energy needed to compensate for the energy lost as unwanted heat. These and other shortcomings are addressed in the present disclosure.
Disclosed herein are systems, methods, and apparatuses relating to various aspects of plasma treatment or processing. In an example apparatus relating to thermal isolation of a workpiece holder assembly, the apparatus comprises a chamber that at least partially defines a processing space for generating plasma to effect a plasma treatment of a workpiece. The apparatus further comprises a base assembly that at least partially defines a lower end of the chamber. An inner perimeter of the base assembly defines an opening in the base assembly. The apparatus further comprises a workpiece holder assembly that is positioned, at least in part, within the opening in the base assembly. The workpiece holder assembly includes a workpiece holder body configured with an outer perimeter and an upper surface. The upper surface is configured to receive a workpiece. One or more heating elements also form the workpiece holder assembly and are in contact with, at least in part, the workpiece holder body. The inner perimeter of the base assembly and the outer perimeter of the workpiece holder body define a gap that circumscribes, at least in part, the workpiece holder body and thermally isolates the base assembly from the workpiece holder body.
In an example method relating to monitoring the cooling of a plasma treated workpiece, the workpiece is positioned at an apparatus configured to perform the plasma treatment. When the plasma treatment is complete, the workpiece is positioned at an unheated cooling station equipped with a temperature sensor. Via the temperature sensor, it is determined that a temperature of the workpiece is below a threshold value. Based on determining that the temperature is below the threshold value, the workpiece is moved away from the cooling station.
In an example system relating to monitoring the cooling of a plasma treated workpiece, the system comprises a transport apparatus, a plasma treatment apparatus, and an unheated cooling station. The plasma treatment apparatus is configured to perform a plasma treatment and the transport apparatus is configured to receive a workpiece. The unheated cooling station is configured with a temperature sensor. The transport apparatus is configured to position the workpiece at the plasma treatment apparatus and, when the plasma treatment is finished, positon the workpiece at the unheated cooling station. The transport apparatus is further configured to determine, via the temperature sensor, that a temperature of the workpiece is below a threshold value. When it is determined that the temperature is below the threshold value, the transport apparatus is configured to receive the workpiece for further positioning.
In an example apparatus relating to liquid cooling a base assembly, such as an electrode or other plasma excitation source of the base assembly, of a plasma treatment apparatus, the apparatus comprises a chamber partially defining a processing space. The apparatus also comprises the base assembly, with the base assembly having an upper surface. The upper surface of the base assembly defines, at least in part, a lower end of the chamber and an opening in the base assembly. A heated workpiece holder is positioned within the opening in the base assembly and configured to receive a workpiece. The apparatus further comprises a plasma excitation source that is operable to provide a plasma in the processing space for treating the workpiece. The apparatus further comprises a liquid cooling conduit that is proximate the plasma excitation source and configured to receive a liquid to cool the plasma excitation source.
In an example apparatus relating to a uniform vacuum in a chamber of the apparatus, the apparatus comprises the chamber partially defining a processing space for receiving process gas. The chamber is under vacuum during treatment of the workpiece with plasma. The apparatus further comprises a base assembly defining a lower end of the processing space. The base assembly comprises a workpiece holder having a perimeter and configured to receive the workpiece. The base assembly further comprises a baffle assembly having a perimeter and surrounding the perimeter of the workpiece holder. The base assembly further comprises a chamber base surrounding the perimeter of the baffle assembly. The workpiece holder has an upper surface that defines at least a second portion of the lower end of the processing space. The apparatus comprises a process gas supply port in the chamber for introducing the process gas to the processing space. The apparatus comprises a plasma excitation source, such as an electrode, to provide plasma in the processing space from the process gas for treating the workpiece. The apparatus comprises an exhaust opening extending continuously around an entirety of the perimeter of the baffle assembly for evacuating said processing space during treatment of the workpiece with plasma.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description, serve to explain the principles of the methods and systems:
Referring to
The base assembly 14 further comprises an electrode 40. The lid assembly 12 likewise comprises a counterpart upper electrode (not shown) that, together with the electrode 40 of the base assembly 14, causes the plasma generation needed to treat a workpiece 26. The base assembly 14 yet further comprises a chamber base 50 that supports, generally, various other components of the base assembly 14, including the aforementioned workpiece holder assembly 20, the lift mechanism 30, and the electrode 40. The chamber base 50 comprises one or more vertical sidewalls 51, each having an upper surface 52.
The base assembly 14 additionally comprises a vacuum plate 60 attached to the bottom of the chamber base 50 and configured with a vacuum space via which non-reacted process gas, plasma, and other byproducts of plasma treatment are drawn to a vacuum pump 61. The vacuum pump 61 is operative to maintain the total pressure in the processing space at a sub-atmospheric level low enough to facilitate plasma generation. A vacuum conduit 62 is attached to the bottom of the vacuum plate 60 at a port in the vacuum plate 60 that leads from the vacuum space. The vacuum conduit 62 enables flow of the drawn process gas, plasma, and other byproduct from the vacuum space to the vacuum pump 61.
The lid assembly 12 is mechanically coupled to a positioning device 16 configured to vertically raise and lower the lid assembly 12 relative to the base assembly 14. In the embodiment shown, the positioning device 16 comprises a pair of couplers, each attached to the lid assembly 12 on one side and mounted on one of a pair of vertical rails on the other side. Vertical movement of the couplers on the vertical rails causes likewise movement of the lid assembly 12 towards or away from the base assembly 14. The positioning device 16 illustrated in
In a raised position, the lid assembly 12 is out of contact with the base assembly 14, as shown in
When the lid assembly 12 is lowered into flush engagement with the base assembly 14 to form a seal therebetween, a chamber is defined by the interior dimensions of the lid assembly 12 and the base assembly 14. A top portion of the chamber may be defined by one or more components of the lid assembly 12. The upper electrode, a bottom surface of the upper electrode in particular, may at least partially define the top portion of the chamber. In addition, inner surfaces of one or more of the sidewalls 18 of the lid assembly 12 may further at least partially define the top portion of the chamber.
A bottom portion of the chamber may be generally defined by upper surfaces of one or more components of the base assembly 14, as best seen in the top down view of
In some embodiments, the lift mechanism 30 may be absent or replaced with another type of lift mechanism. In such an embodiment, the bottom portion of the chamber may be at least partially defined by an otherwise topmost component of the base assembly 14. For example, a base assembly 14 with such a configuration may comprise a baffle plate the same as or similar to the baffle plate described herein. In another example, the lift plates 31 may be replaced by a stationary plate or a stationary component of another type. The stationary plate or other stationary component may be configured with a flat or substantially flat upper surface, for example. The flat or substantially flat upper surface may at least partially define the bottom portion of the chamber.
When so defined by the sealed engagement of the lid assembly 12 and the base assembly 14, the processing space is suitable for plasma processing a workpiece 26 positioned therein. During processing of a workpiece 26, power from a power supply 34 is applied between the electrode 40 of the base assembly 14 and the upper electrode of the lid assembly 12 and produces an electromagnetic field in the processing space. The electromagnetic field excites the atoms or molecules of process gas (provided by a gas supply 36) present in the processing space to a plasma state, which is sustained by the application of power from the power supply 34 for the duration of the plasma treatment.
Constituent species from the plasma contact and interact with exposed material on the workpiece 26 to perform the desired surface modification. The plasma is configured to perform the desired surface modification of the workpiece 26 by selecting parameters such as the chemistry of the process gas, the pressure inside the processing region, and the amount of power and/or frequency applied to the electrodes. The processing system may include an end point recognition system (not shown) that automatically recognizes when a plasma process (e.g., an etching process) has reached a predetermined end point or, alternatively, plasma processes may be timed based upon an empirically-determined time of a process recipe.
As noted, the base assembly 14 includes a workpiece holder assembly 20 comprising a workpiece holder 22 configured to support a workpiece 26 during plasma treatment. For example, the upper surface 24 of the workpiece holder 22 may support the workpiece 26. The workpiece holder assembly 20 is further configured to transfer heat to the workpiece 26 supported by the workpiece holder 22, such as before and/or during plasma treatment of the workpiece 26. Accordingly, the workpiece holder 22 is itself heated. To this end, the workpiece holder assembly 20 comprises one or more heating elements positioned in proximity to, in contact with, or at least partially embedded within the workpiece holder 22. In some embodiments, the workpiece holder 22 may not be heated and thus the heating elements may be omitted from the workpiece holder assembly 20.
As also already noted, the base assembly 14 may further comprise a lift mechanism 30 that is configured to selectively lower a held workpiece 26 onto the workpiece holder 22, such as in anticipation of plasma treatment. The lift mechanism 30 is likewise configured to selectively raise a workpiece 26 from the workpiece's 26 position on the workpiece holder 22, such as upon completion of plasma treatment. The lift mechanism 30 may comprise the one or more stacked lift plates 31 having an inner perimeter 32 (collectively or individually). One or more of the lift plates 31 may be formed in two or more segments that are each separately movable. For example, the top lift plate 31 shown in
One or more of the lift plates 31 may each define a central opening 35 in the respective lift plate 31. The opening 35 is sized according to the size of an anticipated workpiece 26 such that the outer periphery of the workpiece 26 is supported by the lift plate 31 at the inner perimeter 32 (or at least a portion thereof) of the lift plate's 31 opening 35. When moved into the lift plates' 31 lowermost position, as shown in
The plasma treatment system 10 comprises a cooling supply 38 that feeds a cooling system of the base assembly 14, such as one or more cooling conduits. The one or more cooling conduits may be embedded in one or more components of the base assembly 14, such as the electrode 40.
In an example plasma treatment operation of a subject workpiece 26, the lid assembly 12 is in the raised position and the workpiece 26 is positioned on the workpiece holder 22, such as by the lift mechanism 30. The lid assembly 12 is lowered to come into contact with the base assembly 14 and form a seal between the two. A chamber, providing a processing space, is thereby formed. The chamber is held under vacuum by the vacuum pump 61. A process gas from the gas supply 36 is provided to the processing space of the chamber via a process gas inlet 37 of the lid assembly 12. The upper electrode of the lid assembly 12 and the electrode 40 of the base assembly 14 are activated by the power supply 34, thereby causing plasma to be created in the processing space from the process gas. When plasma treatment of the workpiece 26 is complete, the process gas, plasma, and other plasma byproduct are evacuated from the chamber by the vacuum pump 61.
The process gas, plasma, and other plasma byproduct are evacuated via one or more channels or flow paths formed within and/or between various components of the base assembly 14. An example flow path may comprise discrete vertical portions and horizontal (i.e., lateral) portions. The example flow path may alternate between the vertical portions and the horizontal portions. A vertical portion of the flow path may be defined by a vertical passage through one or more of the components of the base assembly 14. A horizontal portion of the flow path may be defined between two components of the base assembly 14. A horizontal length of one or more of the horizontal portions of the flow path is greater than a vertical height of one or more of the vertical portions of the flow path. The horizontal lengths of two or more of the horizontal portions of the flow path are greater than both of the vertical heights of two or more of the vertical portions of the flow path.
The lid assembly 12 is lifted from the base assembly 14 and the plasma treated workpiece 26 is removed. Further iterations of the plasma treatment operation may be then performed.
Plasma Chamber with Uniform Vacuum
With reference to
Beginning with the chamber base 50, the upper portions of the chamber base 50 generally support, at least in part, the electrode 40. The coupling between the chamber base 50 and the electrode 40 may be limited by a thermal break therebetween. One or more O-rings (e.g., a first channel O-ring 94 and a second channel O-ring 92) or other type of sealing element substantially provide the points of contact between the chamber base 50 and the electrode 40, but otherwise allow a space (i.e., a thermal break) therebetween. The vacuum plate 60 is secured to the underside of the chamber base 50. Namely, the vacuum plate 60 is connected to a bottom surface 82 of a floor 80 of the chamber base 50. As already noted, the chamber base 50 comprises the outer side walls 51, each having the upper surfaces 52 and inner surfaces 53. The sidewalls 51 generally enclose, to the sides, the interior components of the chamber base 50.
The chamber base 50 further comprises a channel 58 configured to accommodate a flow of vacuum-drawn process gas, plasma, and other plasma byproduct originated from a plasma treatment in the processing space of the chamber. The channel 58 may be formed as a generally-enclosed conduit and configured to cause a lateral (i.e., along the X and Z axes) flow of the process gas, plasma, and other plasma byproduct within the chamber base 50. The channel 58 may receive the flow of process gas and plasma from one or more openings in a top surface of the channel 58. The flow of process gas and plasma may exit the channel 58 via one or more openings in the bottom surface of the channel 58. At least one top opening to the channel 58 may be offset, along a circumference of the channel 58, from at least one bottom openings from the channel 58. Being offset from one another, the at least one top opening and the at least one bottom opening do not share a vertical (Y) axis. For example, two or more of the top openings to the channel 58 may be offset from two or more of the bottom openings from the channel 58. As another example, each of the top openings to the channel 58 may be offset from each of the bottom openings from the channel 58.
In the embodiment shown in at least
The channel 58 is configured with one or more downward-facing passages 54 defined by, at least in part, and passing through the floor 80 of the chamber base 50. The one or more passages 54 allow flow of the vacuum-drawn process gas, plasma, and other plasma byproduct from the channel 58 to a vacuum space 64 defined by the vacuum plate 60. The one or more passages 54 may be formed at different locations in the channel 58. For example, the one or more passages 54 may be distributed evenly about the circumference of the channel 58. For example, two passages 54 may be located opposite one another in the channel 58. That is, the two passages 54 may be offset from each other by about 180 degrees. As another example, three passages 54 may located in the channel 58 at about 120 degree intervals. Alternatively, the one or more passages 54 may be located at irregular intervals around the channel 58. In the embodiment shown in at least
The chamber base 50 is configured with an interior space 83 that is maintained at ambient pressure during a plasma treatment. The interior space 83 is defined at the sides by an inner surface 85 of the inner circular structure 55. The interior space 83 is defined at the bottom by the upper surface 81 of the floor 80 and at the top primarily by the workpiece holder assembly 20 (e.g., a bottom surface 106 of an insulator piece 104 shown in
The workpiece holder assembly 20 and the electrode 40 are positioned generally vertically above the chamber base 50. The workpiece holder assembly 20 is coupled to the electrode 40 and the electrode 40 is coupled to the chamber base 50. The workpiece holder assembly 20 is coupled to the electrode 40 by coupling a flange 23 of the workpiece holder assembly 20 with the electrode 40 at an inner perimeter 49 of a central opening in the electrode, such that the flange 23 is proximate to—but not in contact with—the underside of the electrode 40. When so coupled, at least an upper portion of the workpiece holder 22 protrudes through the central opening of the electrode 40. The electrode 40 is coupled, in turn, to the chamber base 50 such that an outer surface 47 of a sidewall 44 of the electrode 40 is spaced flush against the inner surface 53 of the sidewall 51 of the chamber base 50. When the workpiece holder assembly 20 is coupled to the electrode 40 and the electrode 40 is coupled to the chamber base 50, the workpiece holder assembly 20 is positioned generally above, but not in direct contact with, the floor 80 of the chamber base 50, thus defining the upper bounds of the interior space 83 of the chamber base 50.
The electrode 40 is configured with a recessed floor 42 having an upper surface 43. The outer bounds of the floor 42 are defined, at least in part, by the inner surface 48 of the sidewall 44 of the electrode 40. The outer bounds of the floor 42 are further defined, at least in part, by convex edges 89 of corresponding corner elements 88. The upper surfaces of the corner elements 88 are flush with the upper surface of the sidewall 44. The corner elements 88 may be considered as comprising part of the sidewall 44. One of the corner elements 88 may be a lift spring assembly 88a.
One or more raised connectors or mounting bosses 45 are positioned at the periphery of the recessed floor 42, next to the inner surface 48 of the sidewall 44. In some embodiments, the raised connectors 45 (or similar raised structures) may be positioned elsewhere on the recessed floor 42. By coupling to the raised connectors 45, the baffle plate 70 is coupled to the electrode 40. A height of the raised connectors 45 may be at a vertical midway point between the recessed floor 42 and the upper surface of the sidewall 44 of the electrode 40. The baffle plate 70 is further coupled with the electrode 40, via connectors 103 (
The recessed floor 42 defines the one or more passages 46, facing downwards, through the electrode 40. The embodiment shown in
As noted above with respect to the passages 54 located in the channel 58 of the chamber base 50, the passages 46 of the electrode 40 are positioned so as to be laterally offset from the passages 54 (e.g., no common vertical axis). For example, at least one of the passages 46 may be offset from at least one of the passages 54. As another example, at least two of the passages 46 may be offset from at least two of the passages 54. Further, each of the passages 46 of the electrode 40 may be offset from all of the passages 54 of the chamber base 50, such as in the embodiment shown in
The offset between the passages 46 of the electrode 40 and the passages 54 of the chamber base 50 may be referred to by a degree of relative offset with respect to the center of the electrode 40 and/or a center of a circumference defined by the inner circular structure 55 or the outer circular structure 56 of the chamber base 50 (e.g., the center of the chamber base 50 or at least the portions of the chamber base 50 relating to the flow of process gas, plasma, and plasma byproduct through the base assembly 14). For example, the degree of relative offset may be about 45 degrees, as is the case in the embodiment shown in
The baffle plate 70 may be coupled to the raised connectors 45 of the electrode 40 to couple the baffle plate 70 generally with the electrode 40. When coupled with the electrode 40, an upper surface 72 of the baffle plate 70 is flush with the upper surface 41 of the electrode 40, including an upper surface of the raised corner 88. The baffle plate 70 comprises the inner perimeter 75 that defines an opening 71 at the center of the baffle plate 70. The inner perimeter 75 of the baffle plate 70 vertically aligns substantially with the inner perimeter 49 of the electrode 40. The opening 71 is configured to accommodate the workpiece holder 22.
The outer perimeter 74 of the baffle plate 70 includes a concave edge 76 that generally corresponds in shape with the convex edge 89 of the raised corner 88. The outer perimeter 74 of the baffle plate 70 is proximate to—but not in direct contact with—the inner surface 48 (which may include the convex edge 89) of the sidewall 44 of the electrode 40. In some embodiments, the entirety of the outer perimeter 74 is proximate to but not in direct contact with the inner surface 48 of the sidewall 44. In other embodiments, the outer perimeter 74 is partially in contact with the inner surface 48 of the sidewall 44 and partially proximate to the inner surface 48 of the sidewall 44 but not in direct contact with the inner surface 48 of the sidewall 44. In yet other embodiments, the majority of the outer perimeter 74 is proximate to but not in contact with the inner surface 48 of the sidewall and a minority of the outer perimeter 74 is in contact with the inner surface 48 of the sidewall 44.
The spatial relationship between the outer perimeter 74 of the baffle plate 70 and the inner surface 48 of the sidewall 44 of the electrode 40 defines the gap 77 through which process gas, plasma, and other plasma byproduct flow from the processing space of the formed chamber. The gap 77 may be elongated along the length (or portion thereof) of the corresponding side of the baffle plate 70 and/or electrode 40.
In some embodiments, the gap 77 on one side of the coupled baffle plate 70 and electrode 40 may be elongated substantially the entire length of the side such that this gap 77 is contiguous with a second gap 77 of the adjoining side. The gap 77 on each of the sides of the coupled baffle plate 70 and electrode 40 may be so configured, thus providing a gap 77 that fully extends around, without break, the outer perimeter 74 of the baffle plate 70. In other embodiments, a gap 77 is elongated along the majority of the length of a side of the coupled baffle plate 70 and electrode 40, but is not contiguous with a second gap 77 of an adjoining side. Thus the gap 77 (here collectively referring to the respective gaps 77 of each side of the coupled baffle plate 70 and electrode 40) may extend around the majority of the outer perimeter 74 of the baffle plate 70 but may comprise breaks in the gap 77. In yet other embodiments, a gap 77 (referring collectively to a broken series of gaps 77) corresponding to a side of the coupled baffle plate 70 and electrode 40 does not extend the majority of the length of the side without one or more breaks. But the gap 77 (again referring collectively to a broken series of gaps 77) nonetheless may cover the majority of the outer perimeter 74 of the baffle plate 70.
In the embodiment shown in
The gap 77 may be configured as, when viewed in vertical cross section of the base assembly 14, a vertical portion 77a (see
The dimensions of the gap 77 may be configured to alter the flow of process gas and plasma through the base assembly 14. For example, a width of 0.5 mm to 2 mm (from the baffle plate 70 to the electrode 40) of the gap 77 may be decreased to constrict the flow of process gas, plasma, and other plasma byproduct while the width of the gap 77 may be increased to increase the flow of process gas, plasma, and other plasma byproduct. The lengthwise dimensions of the gap 77 may be configured to similar effect.
The lift mechanism 30 is coupled to the baffle plate 70 and or electrode 40, with the bottom surface of the lowermost lift plate 31 in contact with the upper surface 72 of the baffle plate 70 and the upper surfaces of the raised corners 88 of the electrode 40. The corners of the lift mechanism 30 cover the space defined between the convex edge 89 of the raised corner 88 and the concave edge 76 of the outer perimeter 74 of the baffle plate 70. The central opening 35 is defined in the lift mechanism 30 and is configured to accommodate, at least in part, the workpiece holder 22.
Below the chamber base 50, an upper surface 68 of a sidewall 66 of the vacuum plate 60 is coupled to the bottom surface 82 of the chamber base 50. A vacuum space 64 is defined by the bottom surface 82 of the chamber base 50, the inner surface 67 of the sidewall 66, and the floor 65 of the vacuum plate 60. The vacuum space 64 is configured to receive process gas, plasma, and other plasma byproduct from the channel 58 via one or more of the passages 54. The floor 65 of the vacuum plate 60 is configured with a port 63 (e.g., only a single port 63) to allow flow of the process gas, plasma, and other plasma byproduct in the vacuum space 64 to the vacuum pump 61.
With particular reference to
With particular reference to
With particular reference to
The base assembly 14 at least in part so-configured and resultant flow paths therethrough (e.g., the flow path 98) may contribute to improved flow characteristics of the processing space and/or the chamber formed by the drawn-together lid assembly 12 and base assembly 14. For example, the improved flow characteristics may include improved uniformity of the process gas, plasma, and other plasma byproducts flow, such as when the process gas, plasma, and other plasma byproducts are vacuum-drawn from the processing space into and through the base assembly 14. In addition, the base assembly 14 configured at least in part according to this disclosure may allow fewer vacuum seals than would otherwise be required because of the single path for exhaust. Further, the base assembly 14 at least in part so-configured may allow for use of a single port access (e.g., the port 63) to evacuate the vacuum space 64 by distributing the vacuum across the vacuum plate 60, acting as a continuous manifold.
With reference to
The workpiece holder assembly 20 and proximate components of the base assembly 14 are configured, individually and collectively, to thermally isolate the workpiece holder assembly 20 from the other proximate components of the base assembly 14. That is, the workpiece holder assembly 20 and the proximate components of the base assembly 14 are configured to minimize heat transfer from the workpiece holder assembly 20 to the proximate portions of the base assembly 14. For example, the workpiece holder assembly 20 comprises the workpiece holder 22, one or more heating elements 25 configured to provide heat to the workpiece holder 22, and an insulator piece 104 configured to minimize heat transfer to other components of the base assembly 14 other than the workpiece holder 22. As another example, the workpiece holder assembly 20 and the proximate components of the base assembly 14 are configured, individually or collectively, to maintain a gap 110 between the workpiece holder 22 and the proximate components of the base assembly 14. The gap 110 affords a thermal break between the workpiece holder 22 and the proximate components of the base assembly 14.
The heating elements 25 may comprise one or more resistance heating elements, for example. The heating elements 25 may be situated so as to be in contact with the workpiece holder 22 and effect heat transfer to the workpiece holder 22. In the workpiece holder assembly 20 shown in
The insulator piece 104 is coupled to the workpiece holder 22 with connectors 99, provided in an alternating arrangement with the circular heating elements 25. When coupled, the insulator piece 104 is held generally in flush engagement, via the insulator piece's 104 top surface 105, with the heating elements 25 and the bottom of the workpiece holder 22. The insulator piece 104 may also serve as a bottom cover to the workpiece holder 22 and heating elements 25. In some embodiments, the workpiece holder assembly 20 may be configured with a separate cover that is situated below the insulator piece 104. The insulator piece 104 is configured with a central opening 113 that exposes the temperature sensor 102 to the ambient pressure interior space 83 between the workpiece holder assembly 20 and chamber base 50. The insulator may be configured to withstand at least 230° Celsius. The insulator piece 104 may be formed from Mica, with a thermal conductivity of about 0.69 W/mK and a maximum service temperature of about 982° Celsius.
In some embodiments, the connectors 99 may be clamps, such as metal clamps. The clamps may be made of stainless steel and have a low profile. The clamps may be located under the insulator piece 104. Three clamps may be provided per heating element 25, although any number greater than one of the clamps may be used to secure each heating element 25. Each clamp can also span one or more heating elements 25, such as two heating elements 25. The clamps may improve the interface between the heating elements 25 and the workpiece holder 22, thereby improving the efficiency of heat transfer to the workpiece holder 22. As such, the energy and temperature of the heating elements 25 may be lowered to achieve a desired temperature of the workpiece holder 22.
The workpiece holder 22 is configured with the outer flange 23 by which the workpiece holder 22 is coupled to the electrode 40. When coupled, a top surface 109 of the flange 23 is proximate to—but not in direct contact with—a bottom surface 108 of the electrode 40 near the inner perimeter 49 of the electrode 40. The space between the top surface 109 of the flange 23 and the bottom surface 108 of the electrode 40 provided by such a coupling may form a horizontal portion of the gap 110 between the workpiece holder 22 and other proximate components of the base assembly 14. The flange 23 of the workpiece holder 22 is coupled to the electrode 40 using one or more connectors, such as bolt connectors. The connectors are not visible at the cross-sections illustrated in
An O-ring 107 or other type of sealing element is provided between the top surface 109 of the flange 23 and the bottom surface 108 of the electrode 40. The O-ring 107 is made from a material configured to minimize heat transfer. Besides the connectors, the O-ring 107 is an additional point of contact between the workpiece holder 22 and the electrode 40. In the embodiment shown in
The gap 110 includes a vertical (or substantially vertical) first portion 110a and a horizontal (or substantially horizontal) second portion 110b. The horizontal second portion 110b corresponds to and is defined by the top surface 109 of the flange 23 and the bottom surface 108 of the electrode 40. Breaks in the horizontal second portion 110b of the gap 110 are limited to those caused by the first channel O-ring 94 and the connectors between the electrode 40 and the flange 23. The horizontal second portion 110b of the gap 110 is contiguous with the vertical first portion 110a.
The vertical first portion 110a generally corresponds with the side 112 of the workpiece holder 22. The vertical first portion 110a spans the side 112 of the workpiece holder 22 between the flange 23 and the upper surface 24 of the workpiece holder 22. The vertical first portion 110a of the gap 110 is defined on the inner side, at least in part, by the side 112 of the workpiece holder 22. The outer side of the vertical first portion 110a is defined, at least in part, by the inner perimeter 49 of the electrode 40. The outer side of the vertical first portion 110a is further defined, at least in part, by the inner perimeter 75 of the baffle plate 70. The outer side of the vertical first portion 110a is yet further defined, at least in part, by the inner perimeter 32 of the lift plates 31 of the lift mechanism 30.
The vertical first portion 110a of the gap 110 is continuous and unbroken in the vertical direction between the flange 23 and the upper surface 24 of the workpiece holder 22. The vertical first portion 110a of the gap 110 is continuous and unbroken horizontally around the side 112 of the workpiece holder 22. Thus the vertical first portion 110a of the gap 110 is unbroken and no point of contact exists between the side 112 of the workpiece holder 22 and any other components of the base assembly 14 (besides other components of the workpiece holder assembly 20 itself).
A cooling conduit 120 is embedded in the electrode 40 and configured to pass a coolant, thereby absorbing heat from the proximate portions of the electrode 40 and other components. The positioning of the cooling conduit 120 proximate the first channel O-ring 94 and the connectors between the flange 23 and the electrode 40 further inhibits heat transfer from the workpiece holder 22.
In one embodiment, the plasma treatment system 10 is associated with an enclosure that defines a workspace for processing a plurality of workpieces 26. The workspace is held at an atmospheric pressure. A workpiece input apparatus is configured to receive the plurality of workpieces from external the enclosure, e.g., from a robot. A plasma treatment apparatus, such as the plasma treatment system 10, is positioned within the enclosure and configured to perform a plasma treatment under a vacuum condition of the plasma treatment apparatus. The pressure in the vacuum condition is less than the atmospheric pressure. A transport apparatus is configured to receive the workpiece from the workpiece input apparatus and position the workpiece at the plasma treatment apparatus for plasma treatment. Although the enclosure is at atmospheric pressure when receiving the workpiece, the size of the enclosure is small enough that the vacuum applied can quickly evacuate the enclosure thereby effectively maintaining a vacuum condition.
Numerous benefits are realized by a base assembly 14 configured according to one or more aspects of the disclosure. For example, by eliminating any direct point of contact, and thus also direct heat transfer, over the vertical first portion 110a of the gap 110 and limiting the direct points of contact over the horizontal second portion 11b of the gap 110 to their connectors and the first channel O-ring 94, superior thermal isolation of the workpiece holder assembly 20 is achieved. The configuration of the heating elements 25 and the insulator piece 104 further contribute to the thermal isolation, as well as allowing for more efficient heat transfer from the heating elements 25 to the workpiece holder 22. The thermal isolation may maintain the other components of the base assembly 14 at a temperature that is safe to the human touch. By maintaining the other components of the base assembly 14 at a safe-to-touch temperature, the need for guards or heat barriers is eliminated or reduced, worker safety is improved, and the footprint of the plasma treatment system 10 is reduced. In addition, since less heat is lost to the other components of the base assembly 14 and the heat transfer from the heating elements 25 to the workpiece holder 22 is improved, less energy is required to power the heating elements 25, thus lowering the cost of operation. The improved thermal isolation and heat transfer also afford reduced heat up times for the plasma treatment system 10.
With further reference to
The electrode 40 is configured with the cooling conduit 120 that is embedded within the electrode 40. The cooling conduit 120 generally encircles the periphery of the electrode 40. The vertical (Y axis) position of the cooling conduit 120 in the base assembly 14 approximately corresponds to the vertical position of the horizontal second portion 110b of the gap 110. The vertical position of the cooling conduit 120 additionally approximately corresponds to the vertical position of the first channel O-ring 94. The cooling conduit is configured with a first portion 120a, a second portion 120b, a third portion 120c, and a fourth portion 120d corresponding to the four sides of the electrode 40, respectively.
The cooling conduit 120 is fed by the cooling supply 38 (
The electrode 40 is configured with a coolant outlet 124 at which coolant, having passed through the cooling conduit 120, exits the fourth portion 120d of the cooling conduit 120. The heated coolant is returned to the cooling supply 38, which may be equipped with one or more heat sinks or the like to dissipate heat from the received coolant. The cooling supply 38 may recycle the coolant back to the cooling conduit 120.
Numerous benefits are realized by the plasma treatment system 10 configured with a liquid cooled electrode 40. For example, the plasma treatment system 10 configured according to at least some aspects of the disclosure relating to liquid cooling the electrode 40 allows for the plasma treatment system 10 to be more compact than otherwise possible. In a system not so configured, a larger air space is required between a heated workpiece holder and the components of the system.
With reference to
The workpiece processing system 200 further comprises a transport device 250 configured to transport the workpiece 226 between devices, stations, workpiece storage or transport containers, or the like. The workpiece processing system 200 further comprises a cooling station 230 configured with a temperature sensor 232. The cooling station 230 may be an unheated cooling station. The cooling station 230 is configured to receive the plasma-treated workpiece 226 (shown in shadow in
The cooling station 230 may be communicatively connected to a controller 240, thus the cooling station 230 may send messages to the controller regarding workpiece temperature. Although not indicated in
The controller may be implemented as a general use computer, specialized hardware, other form of computing device, software, or a combination thereof. In any case, the controller is equipped with a processor and memory. The memory may store instructions that, when executed by the processor, cause the controller to effectuate operations described herein, including those relating to monitoring workpiece cooling. The controller 240 may be further equipped with one or more communication interfaces, including a computer network interface. The controller 240 may be further equipped with one or more input and/or output devices to allow human interaction with the controller 240, such a keyboard, pointing device, and a monitor.
The controller 240 may be integrated with one or more of the components of the workpiece processing system 200. For example, the controller 240 may be integrated with the cooling station 230, the plasma treatment device 220, and/or the transport device 250. Thus, the cooling station 230, the plasma treatment device 220, and/or the transport device 250 so configured may manage and direct operations of the workpiece cooling system 200 with respect to, at the least, cooling the workpiece 226.
The controller 240 is configured to receive data from the cooling station 230, including temperature data describing the temperature of the workpiece 226 and other related aspects, such as elapsed cooling time. The controller 240 processes the temperature data and determines, based on the temperature data, if the workpiece 226 is sufficiently cool and ready to proceed in the associated processing operation. For example, the controller 240 may determine that the workpiece should be transported to another device, station, container, or the like. As an example, the controller 240 may determine if the temperature of the workpiece is below a threshold temperature value. If so, the controller 240 may send a message to the cooling station 230 indicating that the cooling of the workpiece 226 should be deemed complete. Or if the controller 240 determines that the workpiece 226 is not below the threshold temperature value, the controller 240 may send a message to the cooling station 230 indicating that the workpiece 226 should be retained at the cooling station 230 for further cooling.
The workpiece processing system may further comprise a second device 260, such as a device configured to implement further processing of the workpiece. The workpiece processing system 200 comprises or is otherwise associated with a workpiece container 270, such as a Front Opening Universal (or Unified) Pod (FOUP) or Equipment Front End Module (EFEM), configured to receive the treated workpiece 226.
At step 330, a temperature of the workpiece is determined via a temperature sensor (e.g., the temperature sensor 232) associated with the cooling station. The cooling station may comprise the temperature sensor, for example. It is determined, based on the temperature of the workpiece, that the temperature of the workpiece is below a threshold temperature value. The threshold temperature value may be the maximum temperature at which the workpiece may proceed for further processing, for example. The determination that the temperature is below the threshold temperature value may be performed by a controller (e.g., the controller 240) in communication with the cooling station. The controller may send a message to the cooling station indicating whether the temperature of the workpiece is below the threshold temperature value. The controller may additionally or alternatively send a message to the transport device indicating for the transport device to remove the workpiece from the cooling station.
At step 340, based on determining that the temperature has fallen below the threshold temperature value, the workpiece is moved away from the cooling station. The workpiece may be moved away from the cooling station by the transport device, for example. The workpiece may be then transported to a second device (e.g., the second device 260) for further processing of various sorts. Additionally or alternatively, the workpiece may be deposited in a container (e.g., the workpiece container 270) for storage or other transport.
The aspects relating to workpiece cooling monitoring described herein provide numerous benefits. For example, such aspects provide workpiece processing that is faster and results in better quality treated workpieces. For example, a cooling station using a pre-determined, fixed cooling time may allow a workpiece to sit with the cooling station for longer than needed, thereby decreasing throughput efficiency. A cooling station using a pre-determined, fixed cooling time may also signal for the workpiece to be moved from the cooling station prematurely, thereby increasing the number of plasma treated workpieces of unsatisfactory quality.
As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes.
Disclosed are components that may be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that may be performed it is understood that each of these additional steps may be performed with any specific embodiment or combination of embodiments of the disclosed methods.
While the methods and systems have been described in connection with preferred embodiments and specific examples, it is not intended that the scope be limited to the particular embodiments set forth, as the embodiments herein are intended in all respects to be illustrative rather than restrictive.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification.
It will be apparent to those skilled in the art that various modifications and variations may be made without departing from the scope or spirit. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims.
This application is a National Stage Application of International Patent Application No. PCT/US2019/036328, filed Jun. 10, 2019, which claims the benefit of U.S. Provisional Patent App. No. 62/712,051, filed Jul. 30, 2018, the entire disclosures of both of which are hereby incorporated by reference as if set forth in their entirety herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/036328 | 6/10/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62712051 | Jul 2018 | US |
