Patent ID: 12249493

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Semiconductor device fabrication includes many different processes. One such process is performed under an environment with high density plasma (HDP). For example, high-density plasma chemical vapor deposition (HDP-CVD) utilizes high-density plasma directed towards a semiconductor wafer in a reaction chamber to perform film deposition process. To form the high-density plasma, a gas is supplied through a number of nozzles and a power source excites gas mixture with RF or microwave power and directs the plasma ions into a dense region above the semiconductor wafer surface. The main benefit of HDP-CVD is that it can deposit films to fill high aspect ratios. However, much of the challenge for the use of high-density plasma is related not only to the controlling of a flow rate of the gas discharged by gas nozzles but also to the controlling of a wafer temperature. The increased thermal load to the semiconductor wafer may result in a high wafer temperature and cause uneven sputtering rate across the semiconductor wafer. To address this issue, embodiments of the current disclosure provide a wafer chuck having a fluid guiding structure to remove heat from the semiconductor wafer and the wafer chuck. In one example, the fluid guiding structure routes around a center of the wafer chuck in a manner that thermal accumulated on the entire area of the wafer chuck can be removed at substantially the same efficiency, so as to improve uniformity in HDP process.

FIG.1shows a schematic diagram of one embodiment of a wafer fabricating system1for processing a semiconductor wafer5by high density plasma, in accordance with some embodiments. The process performed in the wafer fabricating system1may include HDP-CVD, PECVD, etching, or sputtering processes. However, the wafer fabricating system1is not limited to perform above-mentioned processes and may be used wherever the semiconductor wafer5is processed in an elevated temperature and used a wafer chuck for cooling down temperature.

The semiconductor wafer5may be made of silicon or other semiconductor materials. Alternatively or additionally, the semiconductor wafer5may include other elementary semiconductor materials such as germanium (Ge). In some embodiments, the semiconductor wafer5is made of a compound semiconductor such as silicon carbide (SiC), gallium arsenic (GaAs), indium arsenide (InAs), or indium phosphide (InP). In some embodiments, the semiconductor wafer5is made of an alloy semiconductor such as silicon germanium (SiGe), silicon germanium carbide (SiGeC), gallium arsenic phosphide (GaAsP), or gallium indium phosphide (GaInP). In some embodiments, the semiconductor wafer5includes an epitaxial layer. For example, the semiconductor wafer5has an epitaxial layer overlying a bulk semiconductor. In some other embodiments, the semiconductor wafer5may be a silicon-on-insulator (SOI) or a germanium-on-insulator (GOI) substrate.

The semiconductor wafer5may have various device elements. Examples of device elements that are formed in the semiconductor wafer5include transistors (e.g., metal oxide semiconductor field effect transistors (MOSFET), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJT), high-voltage transistors, high-frequency transistors, p-channel and/or n-channel field-effect transistors (PFETs/NFETs), etc.), diodes, and/or other applicable elements. Various processes are performed to form the device elements, such as deposition, etching, implantation, photolithography, annealing, and/or other suitable processes.

In some embodiments, the wafer fabricating system1includes a chamber10, a processing gas delivery module20, a cleaning gas delivery module30, a wafer holding module40, a gas source50, a fluid containing tank60, a radio frequency module70, a gas exhausting module80, and a control module90. Additional features can be added to the wafer fabricating system1. Some of the features described below can be replaced or eliminated for additional embodiments of the wafer fabricating system1.

The chamber10is configured to contain one or more semiconductor wafer5and is configured to perform a process over the semiconductor wafer5. In some embodiments, the chamber10includes a lower housing11and an upper lid12hinged to the lower housing11and rotatable relative to the lower housing11. In some embodiments, the upper lid12has a dome structure13formed therein. An inner wall of the lower housing11and the dome structure13respectively define a lower boundary and an upper boundary of an air-tight process region within the chamber10for processing the semiconductor wafer5. The lower housing11and the dome structure13may be made of ceramic dielectric material, such as aluminum oxide or aluminum nitride.

The processing gas delivery module20is configured to supply processing gas into the chamber10. In some embodiments, the processing gas delivery module20supplies processing gas into the chamber10via two different paths. For example, the processing gas delivery module20includes a first gas line22and a second gas line26. The first gas line22is connected to a shower head23which is centrally arranged at the dome structure13. Processing gas from a first source21is supplied into the chamber10via the first gas line22and the shower head23. The second gas line26is connected to a gas ring27which circumferentially extends around a lower edge of the upper lid12. A number of gas nozzles29radially extend from the gas ring27toward the process region within the chamber10. Processing gas from a second source25is supplied into the chamber10via the second gas line26, the gas ring27and the gas nozzles29.

As would be understood by a person of skill in the art, while the first gas line22and the second gas line26are connected to different sources, such as first source21and second source25, the actual connection of gas lines to chamber10varies depending on the deposition processes executed within chamber10. The first gas line22and the second gas line26may be connected to the same source, in accordance with some other embodiments. In some embodiments, at least one of the first gas line22and the second gas line26are connected to two or more sources, and different types of source gases are mixed before injecting the gases into the chamber10. The supply of the processing gas from the first source21and the first gas line22may be regulated by the control module90.

The cleaning gas delivery module30is configured to supply cleaning gas into the chamber10after a process over the semiconductor wafer5is completed. In embodiments where flammable, toxic, or corrosive gases are used, it may be desirable to eliminate gas remaining in the chamber10after processing. In some embodiments, the cleaning gas delivery module30includes a gas line32connected to a gas inlet port34formed on a top of the upper lid12. In some embodiments, as shown inFIG.1, the gas inlet port34is arranged such that an end of the first gas line22is received therein and the shower head23is positioned overlapping a discharging end of the gas inlet port34and distant away from the discharging end of the gas inlet port34. Cleaning gas from a source31is supplied into the chamber10via the gas line32, the gas inlet port34and a gap between the discharging end of the gas inlet port34and the shower head23. With the arrangement of the shower head23at the discharging end of the gas inlet port34, the cleaning gas may be evenly distributed into the chamber10. The cleaning gas may include molecular fluorine, nitrogen trifluoride, other fluorocarbons or equivalents.

In some embodiments, the cleaning gas delivery module30further includes a remote plasma generator33. The remote plasma generator33excites the cleaning gas from the source31to a plasma and supplies the plasma to the chamber10via the gas inlet port34. The remote plasma generator33may include a microwave generator. The remote plasma generator33and the gas inlet port34may be made of material that is resistant to attack by the plasma. The remote plasma generator33may be placed close to the gas inlet port34to avoid energy loss of the plasma. Generating the plasma in the remote plasma generator33allows the use of an efficient microwave generator and does not subject components in the chamber10to the temperature, radiation, or bombardment of the glow discharge that may be present in a plasma formed in situ. Consequently, relatively sensitive components, such as wafer holding module40, do not need to be covered with a dummy wafer or otherwise protected, as may be required with an in situ plasma cleaning process.

The wafer holding module40is configured to hold the semiconductor wafer5during the processing. In some embodiments, the wafer holding module40includes a base41, an insulator42, a wafer chuck43, and a number of support pins45. In some embodiments, the base41is electrically connected to a radio frequency (RF) power supply49and acts as an electrode for regulate plasma in the chamber10. The insulator42is disposed between the base41and the wafer chuck43to electrically isolate the base41from the wafer chuck43. The wafer chuck43is configured to secure or position the semiconductor wafer5, for example, by electrostatic force. The wafer chuck43may be made from an aluminum oxide or aluminum ceramic material. A thermal diode (not shown in figures) may be mounted on the wafer chuck43to monitor wafer temperature by detecting, for example, thermal radiation of the wafer chuck43. The support pins45are configured to support the semiconductor wafer5when the semiconductor wafer5is loaded or unloaded on the wafer chuck43by a robot arm (not shown in figures). The support pins45retrack back to the wafer chuck43to place the semiconductor wafer5on a top surface of the wafer chuck43.

FIG.2shows a cross-sectional view of the wafer chuck43taken along a line A-A ofFIG.1. In some embodiments, the wafer chuck43includes a number of inlet ports or outlet ports for engagement of pipings with the wafer chuck43or for facilitating ingress or egress of the fluid to the wafer chuck43. For example, the wafer chuck43includes two gas inlet ports, such as first gas inlet port51and second inlet port55. In addition, the wafer chuck43includes a fluid inlet port61and a fluid outlet port62. In some embodiments, as shown inFIG.1, the first gas inlet port51and the second gas inlet port55(only the first gas inlet port51is illustrated inFIG.1) are fluidly connected to the gas source50. Gaseous material59, such as helium, is supplied to the wafer chuck43through the first gas inlet port51and the second gas inlet port55. Additionally, the fluid inlet port61and the fluid outlet port62are fluidly connected to a fluid containing tank60. Fluid medium69, such as glycol, from the fluid containing tank60is supplied to a fluid guiding structure63formed in the wafer chuck43through the fluid inlet port61and is circulated back to the fluid containing tank60through the fluid outlet port62. The fluid containing tank60may include a heat exchanger (not shown in figures) to cool or heat the fluid medium69. The supply of the gaseous material from the gas source50and the supply of the fluid medium from the fluid containing tank60may be regulated by the control module90.

FIG.3shows a cross-sectional view of the wafer chuck43taken along a line B-B ofFIG.2, andFIG.4shows a cross-sectional view of the wafer chuck43taken along a line C-C ofFIG.2. In some embodiments, the wafer chuck43is placed on the insulator42. An O-ring46is placed in an annular recess460formed on a bottom surface432of the wafer chuck43. The O-ring46is configured to prevent a leakage of fluid or gas from the first gas inlet port51and the second gas inlet port55, the fluid inlet port61and the fluid outlet port62. The insulator42may also include a number of through holes, such as through holes421-424. The through holes421-424are respectively connected to a lower end of the first gas inlet port51, the second gas inlet port55, the fluid inlet port61and the fluid outlet port62for allowing an insertion of the gas piping or fluid piping (not shown in figures) connected to the first gas inlet port51and the second gas inlet port55, the fluid inlet port61and the fluid outlet port62.

Structural features of the wafer chuck43, in accordance with some embodiments of the present disclosure, are described below.

In some embodiments, as shown inFIG.2, the two gas inlet ports51and55are located adjacent to a periphery430of the wafer chuck43. A reference line L passes between the two gas inlet ports51and55and through a center C of the wafer chuck43. The reference line L may be perpendicular to a line connecting the two gas inlet ports51and55.

In some embodiments, the two gas inlet ports51and55are fluidly connected to grooves formed on a top surface of the wafer chuck43. For example, as shown inFIG.3, an inner annular groove435and an outer annular groove437are formed on the top surface431of the wafer chuck43. The inner annular groove435and the outer annular groove437are each formed in an annular shape and arranged concentrically relative to the center C of the wafer chuck43. The outer annular groove437surrounds the inner annular groove435and is located farther away from the center C of the wafer chuck43than the inner annular groove435.

The first gas inlet port51may be fluidly connected to the inner annular groove435through a number of gas channels formed in the wafer chuck43. For example, as shown inFIG.3, the wafer chuck43includes a first lower channel52, a first upper channel53and a first ring-shaped channel54. The first lower channel52vertically extends in the wafer chuck43with a lower end connected to the first gas inlet port51. The first ring-shaped channel54is formed underneath the inner annular groove435and fluidly connected to the inner annular groove435through a number of orifices436formed on a bottom of the inner annular groove435. The first upper channel53extends inclined relative to the first lower channel52and connects the first lower channel52to the first ring-shaped channel54. As such, when a gas piping (not shown in figures) is connected to the first gas inlet port51, gaseous material can be discharged between the semiconductor wafer5and the top surface431of the wafer chuck43through the first lower channel52, the first upper channel53, the first ring-shaped channel54, the orifices436and the inner annular groove435.

The second gas inlet port55may be fluidly connected to the outer annular groove437through a number of gas channels formed in the wafer chuck43. For example, as shown inFIG.4, the wafer chuck43includes a second lower channel56, a second upper channel57and a second ring-shaped channel58. The second lower channel56vertically extends in the wafer chuck43with a lower end connects to the second gas inlet port55. The second ring-shaped channel58is formed underneath the outer annular groove437and fluidly connected to the outer annular groove437through a number of orifices438formed on a bottom of the outer annular groove437. The second upper channel57extends inclined relative to the second lower channel56and connects the second lower channel56to the second ring-shaped channel58. As such, when a gas line (not shown in figures) is connected to the second gas inlet port55, gaseous material can be discharged between the semiconductor wafer5and the top surface431of the wafer chuck43through the second lower channel56, the second upper channel57, the second ring-shaped channel58, the orifices438and the outer annular groove437.

Referring toFIG.2, in some embodiments, the wafer chuck43has a fluid guiding structure63formed therein for guiding a flow of fluid medium in the wafer chuck43. In some embodiments, the fluid guiding structure63extends in the same level of the wafer chuck43which is distant from a top surface431of the wafer chuck43. The fluid guiding structure63extends from a first end channel E1and terminates at a second end channel E2. The first end channel E1is fluidly connected to the fluid inlet port61, and the second end channel E2is fluidly connected to the fluid outlet port62. Between the first end channel E1and the second end channel E2are a number of arc-shaped channels, such as first arc-shaped channel A1, second arc-shaped channel A2, third arc-shaped channel A3and fourth arc-shaped channel A4, and a number of connection channels, such as first connection channel C1, second connection channel C2and third connection channel C3. AlthoughFIG.2illustrates four arc-shaped channels and three connection channels, fluid guiding structure63can include any number of arc-shaped channels and connection channels. In one embodiment, the number of arc-shaped channels is less than 5.

In some embodiments, an upstream end of the first arc-shaped channel A1is connected to a downstream end of the first end channel E1and extends in a circumferential direction of the wafer chuck43. An arc angle of the first arc-shaped channel A1relative to the center C of the wafer chuck43is greater than 180 degrees, for example, the arc angle of the first arc-shaped channel A1is in a range from about 330 degrees to about 355 degrees.

The second arc-shaped channel A2is located at an inner side (i.e., a side that is closer to the center C of the wafer chuck43) of the first arc-shaped channel A1. The second arc-shaped channel A2extends in the circumferential direction of the wafer chuck43. An arc angle of the second arc-shaped channel A2may be less than the arc angle of the first arc-shaped channel A1. In one exemplary embodiment, the arc angle of the second arc-shaped channel A2relative to the center C of the wafer chuck43is greater than 180 degrees, for example, the arc angle of the second arc-shaped channel A2is in a range from about 300 degrees to about 330 degrees.

In some embodiments, as seen from the top view shown inFIG.2, the support pins45are located between the first arc-shaped channel A1and the second arc-shaped channel A2, arranged such that an interference between support pins45and the first arc-shaped channel A1or the second arc-shaped channel A2will not occur. In addition, as seen from the top view shown inFIG.2, the first gas inlet port51and the second gas inlet port55are located between the first arc-shaped channel A1and the second arc-shaped channel A2, arranged such that heat from regions of the wafer chuck43surrounding the first gas inlet port51and the second gas inlet port55can be efficiently dissipated. Details of the process for cooling the wafer chuck will be described in a method in relation toFIG.9.

The third arc-shaped channel A3is located at an inner side of the second arc-shaped channel A2. The third arc-shaped channel A3extends in the circumferential direction of the wafer chuck43. An arc angle of the third arc-shaped channel A3may be less than the arc angle of the second arc-shaped channel A2. In one exemplary embodiment, the arc angle of the third arc-shaped channel A3relative to the center C of the wafer chuck43is greater than 180 degrees, for example, the arc angle of the third arc-shaped channel A3is in a range from about 200 degrees to about 230 degrees.

The fourth arc-shaped channel A4is located at an inner side of the third arc-shaped channel A3. The fourth arc-shaped channel A4extends in the circumferential direction of the wafer chuck43. An arc angle of the fourth arc-shaped channel A4may be greater than the arc angle of the third arc-shaped channel A3. In one exemplary embodiment, the arc angle of the fourth arc-shaped channel A4relative to the center C of the wafer chuck43is greater than 180 degrees, for example, the arc angle of the fourth arc-shaped channel A4is in a range from about 250 degrees to about 300 degrees.

The first connection channel C1connects a downstream end of the first arc-shaped channel A1to an upstream end of the second arc-shaped channel A2. The second connection channel C2connects a downstream end of the second arc-shaped channel A2to an upstream end of the third arc-shaped channel A3. The second connection channel C2may be located immediately adjacent to the fluid inlet port61. The third connection channel C3connects a downstream end of the third arc-shaped channel A3to an upstream end of the fourth arc-shaped channel A4. The third connection channel C3may be located immediately adjacent to the fluid outlet port62. A downstream end of the fourth arc-shaped channel A4is connected to one end of the second end channel E2.

The first connection channel C1, the second connection channel C2and the third connection channel C3may extend in a direction that is parallel to a radial direction of the wafer chuck43or inclined relative to the radial direction of the wafer chuck43. In the exemplary embodiment shown inFIG.2, the first connection channel C1extends in a direction that is substantially parallel to the radial direction of the wafer chuck43. In such embodiment, the first connection channel C1is perpendicular to the first arc-shaped channel A1and the second arc-shaped channel A2.

In addition, the second connection channel C2extend in a direction that is inclined relative to the radial direction of the wafer chuck43. Specifically, the second connection channel C2forms an acute angle with respect to the second arc-shaped channel A2, and the second connection channel C2forms an obtuse angle with respect to the third arc-shaped channel A3. As such, the fluid medium may have a slower flow rate while passing through an intersection point of the second arc-shaped channel A2and the second connection channel C2than that of the fluid medium passing through other channels. Moreover, the fluid medium may have a faster flow rate while passing through an intersection point of the third arc-shaped channel A3and the second connection channel C2than that of the fluid medium passing through other channels. The third connection channel C3may extends in the radial direction of the wafer chuck43.

In some embodiments, for a delivery of a coolant to chill down the wafer chuck43, the coolant in the fluid inlet port61may have a temperature lower than the coolant in the fluid outlet port62. With different intersection angles of the connection channels, the fluid medium in the second connection channel C2may be chilled down by a lower temperature generated by the fluid inlet port61, and the fluid medium in the third connection channel C3may not be heated up by a higher temperature generated by the fluid outlet port62.

In some embodiments, as shown inFIG.2, as seen from a top view, a fan-shaped sector434is defined on the wafer chuck43. The fan-shaped sector434is a circle sector enclosed by a first boundary line B1, a second boundary line B2and an arc located at the periphery430of the wafer chuck43. The central angle α1of the fan-shaped sector434is from about 270 degrees to about 300 degrees. The first gas inlet port51and the second gas inlet port55are located underneath the fan-shaped sector434of the wafer chuck43, and the reference line L passing between the two gas inlet ports51and55forms included angles α2and α3with the first boundary line B1and second boundary line B2. The angle α2is equal to the angle α3. In one exemplary embodiment, the angles α2and α3are in a range from about 120 degrees to about 150 degrees.

In some embodiments, all of the channels of the fluid guiding structure63located underneath of the fan-shaped sector434of the wafer chuck43are formed with an arc shape and is a portion of a circle. For example, segments of each of the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4located underneath of the fan-shaped sector434are parts of circles with different radii.

In some embodiments, all of the channels of the fluid guiding structure63located underneath of the fan-shaped sector434of the wafer chuck43are concentrically arranged relative to the center C of the wafer chuck43. For example, segments of each of the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4located underneath of the fan-shaped sector434are concentrically arranged relative to the center C of the wafer chuck43.

In some embodiments, all of the channels of the fluid guiding structure63located underneath of the fan-shaped sector434of the wafer chuck43are symmetrically arranged relative to the reference line L passing between the two gas inlet ports51and55. For example, segments of each of the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4located underneath of the fan-shaped sector434are symmetrically arranged relative to the reference line L passing between the two gas inlet ports51and55. In other words, segments of each of the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4that are located at two sides of the reference line L have the same arc length from the reference line L to either one of the first boundary line B1or the second boundary line B2.

In some embodiments, all of the channels not extending in the circumferential direction of the wafer chuck43are located outside the fan-shaped sector434. For example, the first connection channel C1, the second connection channel C2, the third connection channel C3, the first end channel E1and the second end channel E2are not located underneath of the fan-shaped sector434. In addition, the fluid inlet port61and the fluid outlet port62are located outside the fan-shaped sector434.

In some embodiments, the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4are spaced apart from each other by different pitches. For example, as shown inFIG.3, the first arc-shaped channel A1is spaced apart from the second arc-shaped channel A2by a first pitch P1, the second arc-shaped channel A2is spaced apart from the third arc-shaped channel A3by a second pitch P2, and the third arc-shaped channel A3is spaced apart from the fourth arc-shaped channel A4by a third pitch P3. The first pitch P1is greater than the second pitch P2, and the second pitch P2is greater than the third pitch P3. In one exemplary embodiment, the first pitch P1is in a range from about 38 mm to about 45 mm, for example, the first pitch P1is 42.14 mm. In one exemplary embodiment, the second pitch P2is in a range from about 28 mm to about 35 mm, for example, the second pitch P2is 28.84 mm. In one exemplary embodiment, the third pitch P3is in a range from about 20 mm to about 25 mm, for example, the third pitch P3is 23.86 mm.

In some embodiments, the outermost channel of the fluid guiding structure63is spaced apart from the periphery430of the wafer chuck43by a distance greater than 0. For example, as shown inFIG.3, the first arc-shaped channel A1is distant away from the periphery430of the wafer chuck43by a distance P0. The distance P0is in a range from about 10 mm to about 15 mm, for example 12 mm. By arranging the first arc-shape channel A1spaced apart from the periphery430of the wafer chuck43, the temperature uniformity in the peripheral region of the wafer chuck43is improved. In some embodiments, as shown inFIG.3, the first arc-shaped channel A1is located underneath a vertical projection of the inner annular groove435. As seen from the top view shown inFIG.3, the outer annular groove437is closer to the periphery430of the wafer chuck43than the first arc-shaped channel A1.

In some embodiments, each of the first connection channel C1, the second connection channel C2, and the third connection channel C3has a length that is substantially the same as the pitch between the arc-shaped channels that are connected at their two ends. For example, the first connection channel C1has a length that is equal to the first pitch P1, the second connection channel C2has a length that is equal to the second pitch P2, and the third connection channel C3has a length that is equal to the third pitch P3. In other words, the length of the first connection channel C1is greater than the length of the second connection channel C2, and the length of the second connection channel C2is greater than the length of the third connection channel C3.

In some embodiments, since the semiconductor wafer5at the central region has a higher temperature than that of the peripheral region of the semiconductor wafer5, due to the configuration of gradually increasing pitch in a direction away from the center C of the wafer chuck43, a higher heat exchange rate is exhibited at the region nearby the center C of the wafer chuck43as compared to the exchange rate at the region adjacent to the periphery430of the wafer chuck43.

In some embodiments, the fluid inlet port61has a width W1(seeFIG.3). In one embodiment, the width W1is in a range from about 25 mm to about 30 mm, for example, the width W1is of about 28 mm. The fluid outlet port62may have the same width as the fluid inlet port61. In some embodiments, the fluid guiding structure63has a uniform dimension for every channel and has a width (or diameter) that is greater than a depth. For example, as shown inFIG.3, the second end channel E2has a depth D in a range from about 8 mm to about 12 mm, for example, the depth D is about 8 mm; and the second end channel E2has a width (or diameter) W2in a range from about 8 mm to about 12 mm, for example, the width W2is about 12 mm.

According to an experimental result, as shown inFIG.5, with a channel having a depth D of about 8 mm and a width W2of about 12 mm, the smallest film thickness uniformity is exhibited. The film thickness uniformity satisfies the following equation:
(TMax−TMin)/2*Tavg*100%
Where TMaxis a maximum thickness measured on the wafer surface, TMinis a minimum thickness measured on the wafer surface, and Tavgis an average thickness measured on the wafer surface. Lower film thickness uniformity may demonstrate a better performance of semiconductor devices.

FIG.6shows a cross-sectional view of a wafer holding module40a, in accordance with some embodiments. The wafer holding module40ais similar to the wafer holding module40shown inFIG.2and like components have like reference numbers. Differences between the wafer holding module40aand the wafer holding module40includes the wafer holding module40areplacing the two gas inlet ports51and55with two gas inlet ports51aand55a.

In some embodiments, the gas inlet port51aand the gas inlet port55aare located adjacent to a periphery430aof the wafer chuck43a. A reference line L passes between the two gas inlet ports51aand55aand through the center C of the wafer chuck43. The reference line L may be perpendicular to a line connecting the two inlet ports51aand55a. In some embodiments, the two gas inlet ports51aand55aare fluidly connected to grooves, such as inner annular groove435and outer annular groove437shown inFIG.3, formed on a top surface of the wafer chuck43. The gas inlet ports51aand55aare located underneath the fan-shaped sector434aof the wafer chuck43a, and the reference line L passing between the gas inlet ports51aand55aforms included angles α5and α6with the first boundary line B1and second boundary line B2. The angle α5is different from the angle α6. In one exemplary embodiment, the angles α5is in a range from about 120 degrees to about 150 degrees, and the angle α6is in a range from about 30 degrees to about 60 degrees.

In the embodiment shown inFIG.6, segments of each of the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4located underneath of the fan-shaped sector434aare asymmetrically arranged relative to the reference line L passing between the gas inlet ports51aand55a. In other words, segments of each of the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4that are located at two sides of the reference line L have different arc lengths from the reference line L to the first boundary line B1or from the reference line L to the second boundary line B2.

FIG.7shows a cross-sectional view of a wafer holding module40b, in accordance with some embodiments. The wafer holding module40bis similar to the wafer holding module40shown inFIG.2and like components have like reference numbers. Differences between the wafer holding module40band the wafer holding module40includes the wafer holding module40breplacing the fluid guiding structure63with fluid guiding structure63band replacing the fluid inlet port61and the fluid outlet port62with a fluid inlet port61band a fluid outlet port62b.

The fluid inlet port61bis located adjacent to a periphery430bof the wafer chuck43b, and the fluid outlet port62bis located at a center C of the wafer chuck43b. In some embodiments, the fluid guiding structure63bis formed with a spiral shape and includes a number of arc-shape channels, such as first arc-shaped channel Alb, second arc-shaped channel A2b, third arc-shaped channel A3b, fourth arc-shaped channel A4band fifth arc-shaped channel A5b. An upstream end of the first arc-shaped channel Alb is connected to the fluid inlet port61band a downstream end of the fifth arc-shaped channel A5bis connected to the fluid outlet port62b. The second arc-shaped channel A2b, the third arc-shaped channel A3b, the fourth arc-shaped channel A4bconsecutively extend from the first arc-shaped channel Alb to the fifth arc-shaped channel A5b.

In some embodiments, each of the first arc-shaped channel Alb, the second arc-shaped channel A2b, the third arc-shaped channel A3b, the fourth arc-shaped channel A4b, and the fifth arc-shaped channel A5bhas a central angle of about 360 degrees. In addition, segments of each of the first arc-shaped channel Alb, the second arc-shaped channel A2b, the third arc-shaped channel A3b, the fourth arc-shaped channel A4b, and the fifth arc-shaped channel A5blocated underneath of the fan-shaped sector434bof the wafer chuck43bare formed with arc shape. Moreover, segments of each of the first arc-shaped channel Alb, the second arc-shaped channel A2b, the third arc-shaped channel A3b, the fourth arc-shaped channel A4b, and the fifth arc-shaped channel A5blocated underneath of the fan-shaped sector434bof the wafer chuck43bare asymmetrically arranged relative to the reference line L passing between gas inlet ports51band55b. The gas inlet ports51band55bmay have similar configuration as the two gas inlet ports51and55.

FIG.8shows a top view of partial elements of a wafer fabricating system, in accordance with some embodiments. In some embodiments, the second gas line26includes an end segment concentrically arranged with the gas ring27relative to the center C of the wafer chuck43, and the second gas line26is connected to the gas ring27through a tube28. The end segment of the second gas line26has a width D1and the gas ring27has a width D2. In some embodiments, the width D1is different from the width D2. For example, the width D1is of about 10 mm and the width D2is of about 12 mm, which significantly improves velocity uniformity of the processing gas supplied from the gas nozzles29.

In some embodiments, as shown inFIG.8, an extension line EL of the tube28passes through the center C of the wafer chuck43. An included angle α7of the extension line EL and the reference line L between the two gas inlet ports51and55is of about 30 degrees to about 50 degrees. In some embodiments, the gas nozzles29located closer to the tube28supply processing gas at a higher velocity as compared to other gas nozzles29away from the tube28. Difference in the velocity of the processing gas may lead to an uneven thickness uniformity. However, since an upstream segment A1U of the first arc-shape channel A1, which conveys cooling medium just entering the fluid guiding structure63, is located adjacent to the tube28, a region of the semiconductor wafer5located above the upstream segment A1U of the first arc-shaped channel A1may have a temperature slightly lower than temperature in other regions. As a result, a film growing rate is optimally regulated and film thickness uniformity is improved.

Referring toFIG.1, in some embodiments, the radio frequency module70is configured to generate RF fields so as to excite plasma in the chamber10. In some embodiments, the radio frequency module70includes a source radio frequency71, a top electrode72and a number of inductive coils73. The source radio frequency71may be connected to the control module90. The control module90is operable to modulate the power output of the source radio frequency71and to deliver the right amount of power to the top electrode72and the inductive coils73for plasma generation. The wafer chuck43is also RF-biased by an RF power supply49. The RF power supply49may be connected to the control module90. The control module90is operable to modulate the power output of the RF power supply49and to deliver the appropriate amount of power to the wafer chuck43.

The gas exhausting module80is configured to remove the gaseous materials or plasma in the chamber10. In some embodiments, the gas exhausting module80includes an exhaust conduit81and a pump82. The exhaust conduit81is connected to the lower portion of the chamber10. The exhaust conduit81may be made of quartz, SiC, Si or any other suitable material commonly used in the art. The pump82is connected to the exhaust conduit81and configured to create the exhaust flow from the chamber10. The flow rate of the exhaust flow in the exhaust conduit81may be adjusted by controlling the output power of the pump82according to a control signal issued from the control module90. The pump82may include, but is not limited to, a turbo-molecular pump.

The control module90controls and directs the fabrication tools, such as the chamber10, the processing gas delivery module20, the cleaning gas delivery module30, the radio frequency module70, and the gas exhausting module80to start and stop various processes involved in the film deposition process. The control module90also controls the supply of the gaseous material from the gas source50and the supply of the fluid medium from the fluid containing tank60.

In some embodiments, the control module90includes a processor91and a memory92. The processor91is arranged to execute and/or interpret one or more set of instructions stored in the memory92. In some embodiments, the processor91is a central processing unit (CPU), a multi-processor, a distributed processing system, an application specific integrated circuit (ASIC), and/or a suitable processing unit. The memory92includes a random access memory or other dynamic storage device for storing data and/or instructions for execution by the processor91. In some embodiments, the memory92is used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor91. In some embodiments, the memory92also includes a read-only memory or other static storage device for storing static information and instructions for the processor91. In some embodiments, the memory92is an electronic, magnetic, optical, electromagnetic, infrared, and/or a semiconductor system (or apparatus or device). For example, the memory92includes a semiconductor or solid-state memory, a magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, and/or an optical disk. In some embodiments using optical disks, the memory92includes a compact disk-read only memory (CD-ROM), a compact disk-read/write (CD-R/W), and/or a digital video disc (DVD).

FIG.9is a flow chart illustrating a method S100for processing semiconductor wafers5, in accordance with some embodiments. For illustration, the flow chart will be described along with the drawings shown inFIGS.1-8and10. Additional operations can be provided before, during, and after the method S100, and some of the operations described can be replaced or eliminated for other embodiments of the method.

The method S100begins with operation S110, in which the semiconductor wafer5is loaded on the top surface431of the wafer chuck43. In some embodiments, the semiconductor wafer5is moved into the chamber10by a robot arm (not shown in figures). The robot arm places the semiconductor wafer5on the support pins45and moves outside of the chamber200. After the semiconductor wafer5is placed on the support pins45, the support pins45lower the semiconductor wafer5, and then the semiconductor wafer5is fixed by the wafer chuck43, as shown inFIG.10.

The method S100also includes operation S120, in which a gaseous material is supplied between the semiconductor wafer5and the top surface431of the wafer chuck43. In some embodiments, the gaseous material is supplied to the wafer chuck43via one or more gas pipings that are connected to the first gas inlet port51and the second gas inlet port55. The gaseous material59from the first gas inlet port51may be delivered to the inner annular groove435through gas channels, such as first lower channel52, first upper channel53, first ring-shaped channel54and orifices436, shown inFIG.3. In addition, the gaseous material59from the second gas inlet port55may be supplied into the outer annular groove437through gas channels, such as second lower channel56, second upper channel57, second ring-shaped channel58and orifices438, shown inFIG.4.

As shown inFIG.10, the gaseous material59filled in the inner annular groove435and the outer annular groove437will continue flowing into a gap formed between the semiconductor wafer5and the top surface431of the wafer chuck43. Most of the gaseous material59from the inner annular groove435is trapped between the semiconductor wafer5and the top surface431of the wafer chuck43by the gaseous material59from the outer annular groove437. Therefore, a gas film is formed between the semiconductor wafer5and top surface431of the wafer chuck43and acts as a heat-transfer medium between the semiconductor wafer5and the wafer chuck43. In some embodiments, the gaseous material59include a gas having a relative high thermal conductivity, such as helium.

The method S100also includes operation S130, in which a fluid medium is supplied to the fluid guiding structure63of the wafer chuck43. In some embodiments, a fluid medium69, such as glycol, is delivered to the fluid guiding structure63for cooling the wafer chuck43. In some embodiments, the fluid medium69is supplied into the fluid guiding structure63at a flow rate in a range from about 0.5 m/s to about 2.0 m/s. According to an experimental result, as shown inFIG.5, in the condition that the fluid medium69is controlled to have a flow rate of about 2.0 m/s, the smallest film thickness uniformity is exhibited.

In some embodiments, the fluid medium69is supplied into the fluid guiding structure63via a piping connected to the fluid inlet port61. After the fluid medium69enters the fluid guiding structure63, the fluid medium69may sequentially flow through the first end channel E1, the first arc-shaped channel A1, the first connection channel C1, the second arc-shaped channel A2, the second connection channel C2, the third arc-shaped channel A3, the third connection channel C3, the fourth arc-shaped channel A4and the second end channel E2. The fluid medium69is then removed from the fluid guiding structure63via another piping connected to the fluid outlet port62.

In some embodiments, the fluid medium69is guided by two arc-shaped channels which are located at two sides of the first gas inlet port51and the second gas inlet port55, and the fluid medium69flows through the two arc-shaped channels in opposite circumferential directions around the center C of the wafer chuck43. For example, as shown inFIG.10, the fluid medium69in the first arc-shaped channel A1flows in a counter-clockwise direction (designated as “X”) relative to the center C of the wafer chuck43, and the fluid medium69in the second arc-shaped channel A2flows in a clockwise direction (designated as “{dot over ( )}”) relative to the center C of the wafer chuck43. The fluid medium69flows through the first arc-shaped channel A1and the second arc-shaped channel A2in opposite circumferential directions around the center C of the wafer chuck43. With such arrangement, the heat in the fan-shaped sector434of the wafer chuck43can be removed efficiently. In addition, the fluid medium69in the third arc-shaped channel A3flows in a clockwise direction (designated as “X”) relative to the center C of the wafer chuck43, and the fluid medium69in the fourth arc-shaped channel A4flows in a counter-clockwise direction (designated as “{dot over ( )}”) relative to the center C of the wafer chuck43. The fluid medium69flows through the third arc-shaped channel A3and the fourth arc-shaped channel A4in opposite circumferential directions around the center C of the wafer chuck43.

In some embodiments, the fluid medium69is guided by the arc-shaped channels that are symmetrical about the reference line L passing between the first gas inlet port51and the second gas inlet port55. For example, the fluid medium69is guided by the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4which are symmetrical about the reference line L passing through between the first gas inlet port51and the second gas inlet port55, as shown inFIG.2. However, it will be appreciated that many variations and modifications can be made to embodiments of the disclosure. In some embodiments, the fluid medium69is guided by the arc-shaped channels that are asymmetrical about a reference line L passing between the first gas inlet port51and the second gas inlet port55. For example, the fluid medium69is guided by the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4which are asymmetrical about the reference line L passing between the first gas inlet port51aand the second gas inlet port55a, as shown inFIG.5. By arranging two arc-shape channels passing through two opposite sides of the gas inlet ports, heat from a portion of the wafer chuck43that is located around the gas inlet ports can be evenly dissipated by both two neighboring arc-shaped channels.

In some embodiments, the fluid medium69is guided by the arc-shaped channels that are concentrically arranged relative to the center C of the wafer chuck43. For example, the fluid medium69is guided by the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4which are concentrically arranged relative to the center C of the wafer chuck43, as shown inFIG.2. Since the arc-shaped channels are concentrically arranged, heat from a portion of the wafer chuck43that is located between two arc-shaped channels can be evenly dissipated by both neighboring arc-shaped channels. As a result, a uniform temperature distribution is exhibited on the semiconductor wafer5.

In some embodiments, the fluid medium69is guided by the arc-shaped channels that are concentrically arranged relative to the center C of the wafer chuck43. For example, the fluid medium69is guided by the first arc-shaped channel A1, the second arc-shaped channel A2, the third arc-shaped channel A3and the fourth arc-shaped channel A4, as shown inFIG.2. The arc angle of the first arc-shaped channel A1is in a range from about 330 degrees to about 355 degrees, the arc angle of the second arc-shaped channel A2is in a range from about 300 degrees to about 330 degrees, the arc angle of the third arc-shaped channel A3is in a range from about 200 degrees to about 230 degrees, and the arc angle of the fourth arc-shaped channel A4is in a range from about 250 degrees to about 300 degrees. Since the arc-shaped channels extend through most of the area of the wafer chuck43, the temperature in the wafer chuck43can be accurately regulated.

In some embodiments, the fluid medium69is guided by one of the arc-shaped channels that is located underneath a vertical projection of the inner annular groove435. For example, as shown inFIG.10, the fluid medium69is guided by the first arc-shape channel A1, and the first arc-shape channel A1is located underneath a vertical projection of the inner annular groove435.

In some embodiments, the fluid medium69from the fluid inlet port61first flows through an arc-shaped channel that is farthest away from the center C of the wafer chuck43and flows to another arc-shaped channel that is located closer to the center C of the wafer chuck43. For example, the fluid medium69from the fluid inlet port61flows through the first arc-shaped channel A1prior to the second arc-shaped channel A2.

The method S100also includes operation S140, in which a plasma gas is supplied over the semiconductor wafer5. In some embodiments, the RF power is applied to the dome structure13and the wafer chuck43by the radio frequency module70and the RF power supply49, and the plasma is excited between the dome structure13and the wafer chuck43. In some embodiments, as shown inFIG.10, the plasma gas15is directed toward the semiconductor wafer5so as to form a thin film on the semiconductor wafer5in a HDP-CVD process, or recess a material formed on the semiconductor wafer5in an etching process.

The method S100also includes operation S150, in which the semiconductor wafer5is unloaded from the wafer chuck43. In some embodiments, after the completion of the process in the chamber10, the semiconductor wafer5is lifted by the support pins45, and is removed from the chamber10through the robot arm (not shown in figures).

It is understood that the semiconductor wafer fabricated according to the present disclosed methods undergoes further processes. For example, after the semiconductor wafer5formed with a thin film is removed from the wafer fabricating system1, the semiconductor wafer5is sent to a chemical-mechanical polishing (CMP) system for a planarization process. It will be appreciated that since the thin films formed on the semiconductor wafer5have a higher uniformity as compared with those handled by a conventional wafer chuck, process parameters utilized in the planarization process can be set according to a regular recipe without spending additional time for reworking. As a result, a tool availability of CMP system is increased, and the usage of a slurry in the CMP system is reduced.

The semiconductor wafer5may undergo additional processes including material deposition, implantation, or etching operations, to form various features such as field effect transistors, cap insulating layers, contacts/vias, silicide layers, interconnect metal layers, dielectric layers, passivation layers, metallization layers with signal lines, or the like. In some embodiments, one or more layers of conductive, semiconductive, and insulating materials are formed over the substrate, and a pattern is formed in one or more of the layers.

Embodiments of a wafer fabricating system use a wafer chuck to cool the semiconductor wafer. The fluid guiding structure for guiding a heat exchanging medium in the wafer chuck includes a number of arc-shaped channels arranged next to gas inlet ports for receiving helium gas. Since heat accumulated at regions of the wafer chuck around the gas inlet ports can be efficiently removed, a more uniform processing is likely to occur on the semiconductor wafer being processed. According to one experimental result in HDP-CVD process, the film thickness uniformity decreases about 0.8% from 1.57% to 0.78% as compared to semiconductor wafer cooled by a conventional wafer chuck.

In accordance with some embodiments, a method for processing semiconductor wafer is provided. The method includes loading a semiconductor wafer on a top surface of a wafer chuck. The method also includes supplying a gaseous material between the semiconductor wafer and the top surface of the wafer chuck through a first gas inlet port and a second gas inlet port located underneath a fan-shaped sector of the top surface. The method further includes supplying a fluid medium to a fluid inlet port of the wafer chuck and guiding the fluid medium from the fluid inlet port to flow through a number of arc-shaped channels located underneath the fan-shaped sector of the top surface. In addition, the method includes supplying a plasma gas over the semiconductor wafer.

In accordance with some embodiments, a method for processing semiconductor wafer is provided. The method includes loading a semiconductor wafer on a top surface of a wafer chuck. The method also includes supplying a gaseous material between the semiconductor wafer and the top surface of the wafer chuck through a gas inlet port of the wafer chuck. The method further includes supplying a fluid medium to a fluid inlet port of the wafer chuck and guiding the fluid medium from the fluid inlet port to flow through a first arc-shaped channel and a second arc-shaped channel which are located at opposite sides of the gas inlet port. The second arc-shaped channel is located closer to a center of the wafer chuck than the first arc-shaped channel, and the fluid medium from the fluid inlet port flows through the first arc-shaped channel prior to the second arc-shaped channel. In addition, the method includes supplying a plasma gas over the semiconductor wafer.

In some embodiments, a wafer fabricating system includes a wafer chuck, a gas inlet port, a fluid inlet port, first and second arc-shaped channels, a gas source, and a fluid containing source. The wafer chuck has a top surface, and orifices are formed on the top surface. The gas inlet port is formed in the wafer chuck and located underneath a fan-shaped sector of the top surface, wherein the gas inlet port is fluidly communicated with the orifices. The fluid inlet port is formed in the wafer chuck. The first and second arc-shaped channels are fluidly communicated with the fluid inlet port and located underneath the fan-shaped sector of the top surface and located at opposite sides of the gas inlet port from a top view. The gas source fluidly is connected to the gas inlet port. The fluid containing source fluidly is connected to the fluid inlet port. In some embodiments, the first and second arc-shape channels are concentrically arranged relative to a center of the wafer chuck. In some embodiments, the first and second arc-shape channels have arc angles greater than about 180 degrees relative to a center of the wafer chuck. In some embodiments, the second arc-shaped channel has a greater arc angle than the first arc-shaped channel. In some embodiments, the wafer fabricating system further includes a linear connection channel connecting the first arc-shaped channel to the second arc-shaped channel. In some embodiments, the wafer fabricating system further includes a third arc-shaped channel fluidly communicated with the fluid inlet port, wherein the first, second, and third arc-shaped channels are arranged in order along a direction toward a center of the wafer chuck. In some embodiments, the wafer fabricating system further includes a linear connection channel connecting the second arc-shaped channel to the third arc-shaped channel. In some embodiments, the fluid inlet port is located at an outside of the fan-shaped sector of the wafer chuck from the top view. In some embodiments, the wafer fabricating system further includes a fluid outlet port in the wafer chuck and fluidly communicated with the first and second arc-shaped channels, the fluid outlet port being located at an outside of the fan-shaped sector of the wafer chuck. In some embodiments, the wafer fabricating system further includes an inner annular groove formed on the top surface of the wafer chuck and fluidly communicated with the gas inlet port, the inner annular groove overlapping the second arc-shaped channel.

In some embodiments, a wafer fabricating system includes a process chamber, a wafer chuck, a first arc-shaped cooling channel, a second arc-shaped cooling channel, and a fluid containing source. The wafer chuck is in the process chamber. The first arc-shaped cooling channel is disposed in the wafer chuck. The second arc-shaped cooling channel is disposed in the wafer chuck and fluidly communicated with the first arc-shaped cooling channel. The first and second arc-shaped cooling channels are concentric about a center of the wafer chuck from a top view. The fluid containing source fluidly is connected to the first and second arc-shaped cooling channels. In some embodiments, the wafer fabricating system further includes a third arc-shaped cooling channel disposed in the wafer chuck and fluidly communicated with the first and second arc-shaped cooling channels, the first, second, and third arc-shaped cooling channels being concentric about the center of the wafer chuck from the top view. In some embodiments, the wafer fabricating system further includes a first linear connection channel connecting the first arc-shaped cooling channel to the second arc-shaped cooling channel, and a second linear connection channel connecting the second arc-shaped cooling channel to the third arc-shaped cooling channel. In some embodiments, the first linear connection channel has a longer length than the second linear connection channel. In some embodiments, the second arc-shape cooling channel surrounds the first arc-shape cooling channel and has an arc angle greater than about 180 degrees relative to the center of the wafer chuck.

In some embodiments, a wafer fabricating system includes a deposition chamber, a shower head, a wafer chuck, a fluid guiding structure, and a fluid containing source. The shower head is in the deposition chamber. The wafer chuck is in the deposition chamber and below the shower head. The fluid guiding structure is disposed in the wafer chuck. The fluid guiding structure includes a plurality of arc-shaped channels. The arc-shaped channels each have an arc angle greater than about 180 degrees relative to a center of the wafer chuck from a top view. The fluid containing source is fluidly connected to the fluid guiding structure. In some embodiments, a first one of the arc-shaped channel has a greater arc angle than a second one of the arc-shaped channels. In some embodiments, the wafer fabricating system further includes a linear connection channel connecting the first one of the arc-shaped channel to the second one of the arc-shaped cooling channels. In some embodiments, the wafer fabricating system further includes a gas inlet port and a gas source. The gas inlet port is in the wafer chuck and fluidly communicated with orifices formed on the wafer chuck. The gas inlet port is located between the second and third arc-shaped channels from the top view. The gas source is fluidly connected to the gas inlet port. In some embodiments, a third one of the arc-shaped channel has a greater arc angle than the first one of the arc-shaped channels. In some embodiments, the arc-shaped channels are at a same level height.

In some embodiments, a method includes loading a wafer over a wafer chuck in a process chamber; performing a deposition process on the loaded wafer; supplying a fluid medium to a fluid guiding structure in the wafer chuck from a fluid inlet port on the wafer chuck, the fluid guiding structure comprising a plurality of arc-shaped channels fluidly communicated with each other; guiding the fluid medium from a first one of the arc-shaped channels of the fluid guiding structure to a second one of the arc-shaped channels of the fluid guiding structure concentric with the first one of the arc-shaped channels from a top view. In some embodiments, the second one of the arc-shaped channels is located closer to a center of the wafer chuck than the first one of the arc-shaped channels. In some embodiments, the first one of the arc-shaped channels has a greater arc angle than the second one of the arc-shaped channels. In some embodiments, the first and second ones of the arc-shape channels have arc angles greater than about 180 degrees relative to a center of the wafer chuck. In some embodiments, the fluid medium flows through the first and second ones of the arc-shaped channels in opposite circumferential directions around a center of the wafer chuck. In some embodiments, the fluid guiding structure further comprises a linear connection channel connecting the second one of the arc-shaped channels to the first one of the arc-shaped channels. In some embodiments, the fluid medium flows through the first and second ones of the arc-shaped channels in a same circumferential direction around a center of the wafer chuck. In some embodiments, the fluid guiding structure has a third one of the arc-shaped channels between the first and second ones of the arc-shaped channels and concentric with the first and second ones of the arc-shaped channels from the top view. In some embodiments, the fluid medium flows through the first and third ones of the arc-shaped channels in opposite circumferential directions around a center of the wafer chuck. In some embodiments, the method includes guiding a gaseous material from a gas inlet port on a bottom surface of the wafer chuck to an inner annular groove on a top surface of the wafer chuck; supplying the gaseous material between the wafer and the wafer chuck from the inner annular groove.

In some embodiments, a method includes holding a wafer over a wafer chuck in a process chamber; supplying a fluid medium to a fluid inlet port on the wafer chuck; guiding the fluid medium from the fluid inlet port to a first arc-shaped cooling channel disposed in the wafer chuck; after guiding the fluid medium from the fluid inlet port to the first arc-shaped cooling channel, guiding the fluid medium from the first arc-shaped cooling channel to a second arc-shaped cooling channel disposed in the wafer chuck, the fluid medium flowing in a first circumferential direction in the first arc-shaped cooling channel and in a second circumferential direction opposite to the first circumferential direction in the second arc-shaped cooling channel; generating plasma in the process chamber. In some embodiments, the first arc-shaped cooling channel surrounds the fluid inlet port from a top view. In some embodiments, the second arc-shaped cooling channel surrounds the fluid inlet port from a top view. In some embodiments, the method includes discharging the fluid medium through a fluid outlet port on the wafer chuck, wherein the first arc-shaped cooling channel surrounds the fluid outlet port from a top view. In some embodiments, the first arc-shaped cooling channel has a different arc angle than the second arc-shaped cooling channel. In some embodiments, the method includes after guiding the fluid medium from the first arc-shaped cooling channel to the second arc-shaped cooling channel, guiding the fluid medium from the second arc-shaped cooling channel to a third arc-shaped cooling channel disposed in the wafer chuck.

In some embodiments, a method includes depositing a film on a wafer over a wafer chuck in a process chamber; supplying a fluid medium to a first arc-shaped cooling channel disposed in the wafer chuck; guiding the fluid medium from the first arc-shaped cooling channel to a second arc-shaped cooling channel disposed in the wafer chuck, the second arc-shaped channel being closer to a center of the wafer chuck than the first arc-shaped channel from a top view. In some embodiments, guiding the fluid medium from the first arc-shaped cooling channel to the second arc-shaped cooling channel is performed through a first linear connection channel connecting between the first and second arc-shaped cooling channels. In some embodiments, the method includes guiding the fluid medium from the second arc-shaped cooling channel to a third arc-shaped cooling channel disposed in the wafer chuck. In some embodiments, guiding the fluid medium from the second arc-shaped cooling channel to the third arc-shaped cooling channel is performed through a second linear connection channel connecting between the first and second arc-shaped cooling channels, the second linear connection channel having a shorter length than the first linear connection channel.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.