Method and Apparatus for Substrate Temperature Control

Methods and apparatus for controlling substrate temperature includes: measuring a substrate that has undergone a deposition process; analyzing measurements of the substrate to detect a defect of the substrate; and sending a feedback signal to modify a temperature control parameter of a temperature controller used in controlling a temperature of the substrate in the deposition process based on the analyzing if a defect is detected, and not sending a feedback signal to modify the temperature control parameter if a defect is not detected.

FIELD

Embodiments of the present disclosure generally relate to methods, systems, and apparatus for substrate temperature control.

BACKGROUND

AC bias is sometimes used during deposition of aluminum (Al) films (e.g., PVD deposition) on substrates. The AC bias is used to improve Al coverage on the substrate. However, the inventors have observed that AC bias can undesirably increase the temperature on substrates due to bombardment of certain portions of the substrate by argon radicals. The increased temperature can degrade the film morphology by increasing the roughness of the film surface, which can be measured as a reduction in reflective index (RI). Increased film roughness during Al deposition, may be exacerbated during downstream processing involving heat treatment, such as annealing.

Moreover, during Al deposition, outer edges of an electrostatic chuck may become contaminated. Such contamination may interfere with contact between the outer portion of the substrate and the surface of the electrostatic chuck, leading to reduced efficiency in heat transfer and higher temperatures around the outer portion of the substrate.

The inventors propose novel methods and apparatus for substrate temperature control that can improve film morphology and mitigate the effects of reduced efficiency in heat transfer of the electrostatic chuck.

SUMMARY

Methods and apparatus for controlling substrate temperature are provided herein. In some embodiments, a method for controlling substrate temperature includes: measuring a substrate that has undergone a deposition process; analyzing measurements of the substrate to detect a defect of the substrate; and sending a feedback signal to modify a temperature control parameter of a temperature controller used in controlling a temperature of the substrate in the deposition process based on the analyzing if a defect is detected, and not sending a feedback signal to modify the temperature control parameter if a defect is not detected.

In some embodiments, a system for controlling substrate temperature includes: a measurement chamber configured to house a substrate that has undergone a deposition process; a measurement device coupled to the measurement chamber configured to measure at least a portion of the substrate when disposed in the measurement chamber; an analysis device configured to analyze measurements of the substrate and detect a defect of the substrate; and a controller configured to send a feedback signal to modify a temperature control parameter of a temperature controller used in controlling a temperature of the substrate in the deposition process based on the analysis if a defect is detected and to not send a feedback signal to modify the temperature control parameter if a defect is not detected.

In some embodiments, a non-transitory computer readable storage medium having instructions stored thereon that, when executed, perform a method for controlling substrate temperature, wherein the method includes: measuring a substrate that has undergone a deposition process; analyzing measurements of the substrate to detect a defect of the substrate; and sending a feedback signal to modify a temperature control parameter of a temperature controller used in controlling a temperature of the substrate in the deposition process based on the analyzing if a defect is detected, and not sending a feedback signal to modify the temperature control parameter if a defect is not detected.

DETAILED DESCRIPTION

Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the disclosure depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of scope, for the disclosure may admit to other equally effective embodiments.

Embodiments of methods, systems, and apparatus for controlling substrate temperature are provided herein. Such methods, systems, and apparatus can provide substrate temperature control based on defects detected in a processed substrate. By considering the defects in the substrate, the effects of AC bias induced surface degradation and electrostatic chuck contamination can both be reduced, while also avoiding manual heater adjustments, preventive maintenance, and downtime.

FIG.1is a schematic view of a system100in accordance with embodiments of the present disclosure. In some embodiments the system100may include a process chamber102and a substrate support104disposed in the process chamber102. The process chamber102may be configured to perform substrate processing on a substrate108. In some embodiments, the process chamber102may be a PVD chamber configured to perform PVD deposition processing on the substrate108. In some embodiments, and as show inFIG.1, the substrate support104may have a support surface106to support the substrate108during substrate processing in the process chamber102. In some embodiments, and as shown inFIG.1, the substrate support104may have a plurality of zones109(a first zone110near a center of the substrate support104, and a second zone112near an edge of the substrate support104are shown inFIG.1). In some embodiments, the substrate support104is circular and the plurality of zones include at least one of a circular zone or an annular zone. The system100may also include a sputtering target114disposed in the process chamber102opposite the support surface106and the substrate108. In some embodiments, the sputtering target114may include aluminum. The system100may also include a plurality of temperature sensors115(a first temperature sensor116, a second temperature sensor118, and a third temperature sensor120are shown inFIG.1), each of which is configured to sense temperature in a corresponding zone of the plurality of zones109. For example, inFIG.1, the first temperature sensor116is configured to sense temperature in the first zone110, and the second temperature sensor118and the third temperature sensor120are configured to sense temperature in the second zone112. In some embodiments, the temperature in each zone of the plurality of zones109may be monitored by one corresponding temperature sensor located in each zone.

The system100may also include a multizone temperature control system111for controlling the temperature of the plurality of zones109and, thus, a temperature of the substrate108during deposition processing in the process chamber102. In some embodiments, the temperature control system111may be configured to independently control the temperature in each zone of the plurality of zones109. In some embodiments, and as shown inFIG.1, the temperature control system111may include a plurality of temperature elements121, each of which corresponds to a zone of the plurality of zones109(e.g., a first temperature element122and a second temperature element124are shown inFIG.1). For example, in the embodiment shown inFIG.1, the first temperature element122corresponds to the first zone110and the second temperature element124corresponds to the second zone112.

The temperature elements121may include at least one of a heating element or a coolant loop. In some embodiments, a heating element may include a resistive heating element, and in some embodiments a coolant loop may include a fluid channels configured for directing a heat transfer fluid, such as water. In some embodiments, and as shown inFIG.1, the plurality of zones109may be arranged as circles or annular regions of the substrate support104and the plurality of temperature elements121may be arranged to extend concentrically in one or more zones of the plurality of zones109.

In some embodiments, and as shown inFIG.1, the temperature control system111may include a temperature controller126configured to independently control each temperature element of the plurality of temperature elements121based on measurements of the substrate108, as discussed more fully below. In some embodiments where heating elements are present, the temperature controller126may include at least one driver128configured as a heater driver connected to the plurality of heating elements and to a supply130configured as a power supply, and the driver128may be configured to control power output to each heating element. In some embodiments where coolant loops are present, the temperature controller126may include at least one driver128configured as a flow driver connected to the plurality of separate fluid channels and to a supply130configured as a fluid supply, and the driver128may be configured to control fluid flow through each fluid channel.

In some embodiments, the temperature controller126may include a processor132(programmable) that is operable with a memory134and a mass storage device, an input control unit, and a display unit (not shown), such as power supplies, clocks, cache, input/output (I/O) circuits, the driver128, and support circuits136coupled to the various components of the processing system to facilitate control of the substrate processing. Support circuits136may be coupled to the processor132for supporting the processor132in a conventional manner.

To facilitate control of the system100described above, the processor132may be one of any form of general-purpose computer processor that can be used in an industrial setting, such as a programmable logic controller (PLC), for controlling various chambers and sub-processors. The memory134coupled to the processor132and the memory134can be non-transitory computer readable storage medium and may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage, local or remote. Charged species generation, heating, deposition and other processes are generally stored in the memory134, typically as software routine. The software routine may also be stored and/or executed by a second processor (not shown) that is remotely located from the system100being controlled by the processor132.

The memory134may be in the form of computer-readable storage media that contains instructions, which when executed by the processor132, facilitates the operation of the system100. The instructions in the memory134may be in the form of a program product such as a program that implements the method in accordance with embodiments of the present disclosure. The program code may conform to any one of a number of different programming languages. In one example, the disclosure may be implemented as a program product stored on a computer-readable storage media for use with a computer system. The program(s) of the program product define functions of the embodiments (including the methods described herein). Illustrative non-transitory computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. Such non-transitory computer-readable storage media, when carrying computer-readable instructions that direct the functions of the methods described herein, are embodiments of the present disclosure.

FIG.1also shows a substrate measurement system160in communication with the system100in accordance with embodiments of the disclosure. In some embodiments, the substrate measurement system160may be configured to measure the substrate108and send a feedback signal to the temperature controller126to adjust temperature control parameters (e.g., temperature setpoints) of the temperature controller126. In some embodiments, the substrate measurement system160may be configured to measure at least one of reflective index (RI) of a sputter-deposited surface of the substrate108, sheet resistance of the substrate108, film thickness of a sputter deposited film, or resistivity of a portion of the substrate108. Such measurements may be used to indicate defects of the sputter-deposited surface of the substrate108. The detected defects are those caused at least in part by substrate temperature during deposition processing in the process chamber102.

In some embodiments, the substrate measurement system160may include a measurement chamber162, at least one measurement device164configured to measure properties of the substrate108, and an analysis device166configured to determine whether the substrate108includes defects or defects resulting from deposition processing. In some embodiments, and as shown inFIG.1, the measurement chamber162may be separate from the process chamber102. For example, in some embodiments, the measurement chamber162and the process chamber102may be part of a common cluster tool180for processing substrates, such as a PVD Cluster tool available from Applied Materials of Santa Clara, California, in which the substrate108may be transferred between the process chamber102and the measurement chamber162. In some embodiments, and as shown inFIG.1, the substrate108may be supported in the measurement chamber162by a substrate support168so that the substrate108is disposed opposite the measurement device164.

Also, in some embodiments, the measurement device164and the analysis device166may be remote from one another. Also, in some embodiments, the measurement device164and the analysis device166may be combined together in a single device. In some embodiments, the measurement device164may include a non-contact measurement device.

Such non-contact measurement device may include an image acquisition device (e.g., a camera or a microscope) for acquiring images of at least one portion of the substrate108and an image processor for processing acquired images of the substrate108. In some embodiments, the acquired images may be processed and/or stored locally on the measurement device164or remotely (e.g., on a server or in the cloud) from the measurement device164.

In some embodiments, the measurement device164may be configured to measure at least one of reflective index of a deposited surface of the substrate108, a deposited film thickness, or resistivity of at least a portion of the substrate108.

The analysis device166may analyze acquired and/or processed images to measure and detect defects on the substrate108. In some embodiments, the analysis device166is configured to inspect acquired and/or processed images for the presence of a defect. For example, the analysis device166may be configured to compare measurements to predetermined measurements for determining the presence of a defect. In some embodiments, the analysis device166may be configured to inspect acquired images for the presence and clarity of an alignment mark on the substrate108. For example, in some embodiments, the substrate measurement system160may be configured to optically identify features (e.g., an alignment mark) on one or more portions of the substrate108to detect the presence of a defect and send feedback to the temperature controller126based on a detection of a defect.

For example, one or more alignment marks may be present along an outer edge of the substrate108. A blurry image of the alignment mark(s), which may be optically detected by the substrate measurement system160, may indicate that the temperature of the substrate108at or near the alignment mark was too high during deposition processing in the process chamber102.

Also, in some embodiments, the non-contact measurement device may be configured to measure resistivity of at least a portion of the substrate108. The analysis device166may compare the resistivity measurements to a predetermined range of acceptable resistivity. A measurement that exceeds a predetermined range of acceptable resistivity may be indicative of a defect caused by substrate temperature being too low during deposition processing, while a resistivity measurement that is less than the predetermined range may be indicative of a defect caused by substrate temperature being too high during deposition processing.

In some embodiments, the analysis device166may be configured to determine, for each detected defect, one or more zone of the plurality of zones109corresponding to a location of the defect on the substrate108. For example, in some embodiments, as described above, the analysis device166may determine that the temperature in one or more zones of the plurality of zones109are at least partial causes of the detected defect.

In some embodiments, to reduce or prevent the detected defects from occurring in subsequent substrates to be processed in the process chamber102, the analysis device may send a feedback signal to the temperature controller126to modify a temperature control parameter of the temperature controller126. In some embodiments, the temperature control parameter may include a temperature setpoint of one or more zones of the plurality of zones109that are determined to be at least partial causes of the detected defect. For example, where the analysis device166determines that a defect was the result of a temperature that was too high, the feedback signal may include temperature setpoints that are lower than those used during the substrate processing of substrate108. Similarly, where the analysis device166determines that a defect was the result of a temperature that was too low, the feedback signal may include temperature setpoints that are higher than those used during the substrate processing of substrate108.

In some embodiments, the temperature control parameters may include tuning parameters for tuning the driver128(e.g., heater driver) of the temperature controller126to control driver output to one or more of the plurality of temperature elements121. For example, where the temperature elements121include heating elements, the feedback signal may include a signal to adjust power output to one or more heater elements corresponding to a determined location of a detected defect of the substrate. The power output of the heating elements may be adjusted to change the control characteristics and responsiveness of the heater (e.g., control ramp rate, duty cycle, damping, and overshoot.)

In some embodiments, the analysis device166may include a processor170(programmable) that is operable with a memory172and a mass storage device, an input control unit, and a display unit (not shown), such as power supplies, clocks, cache, input/output (I/O) circuits176, and support circuits174coupled to the various components of the processing system to facilitate control of the substrate processing. Support circuits174may be coupled to the processor170for supporting the processor170in a conventional manner.

To facilitate control of the analysis device166described above, the processor170may be one of any form of general-purpose computer processor that can be used in an industrial setting, such as a programmable logic controller (PLC). The memory172coupled to the processor170and the memory172can be non-transitory computer readable storage medium and may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage, local or remote. Substrate measurement and inspection processes are generally stored in the memory172, typically as software routine. The software routine may also be stored and/or executed by a second processor (not shown) that is remotely located from the analysis device being controlled by the processor170.

The memory172may be in the form of computer-readable storage media that contains instructions, which when executed by the processor170, facilitates the operation of the analysis device166. The instructions in the memory172may be in the form of a program product such as a program that implements the method in accordance with embodiments of the present disclosure. The program code may conform to any one of a number of different programming languages. In one example, the disclosure may be implemented as a program product stored on a computer-readable storage media for use with a computer system. The program(s) of the program product define functions of the embodiments (including the methods described herein). Illustrative non-transitory computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. Such non-transitory computer-readable storage media, when carrying computer-readable instructions that direct the functions of the methods described herein, are embodiments of the present disclosure.

FIG.2shows a method200for controlling substrate temperature in accordance with embodiments of the present disclosure. In some embodiments, at202, the method begins when a substrate (e.g.,108) that has undergone a deposition process in process chamber102is received in the measurement chamber162and placed on the substrate support168in preparation for measurement of the substrate108. For example, in some embodiments, the substrate108may be processed in the process chamber102and then transferred within cluster tool180to the measurement chamber162to be measured. Thus, in some embodiments, the substrate108received in the measurement chamber162may have a sputter-deposited surface deposited in the process chamber102.

At204, the substrate108may be measured by the measurement device164. In some embodiments where the measurement device164includes an image acquisition device, such as a camera or microscope, the image acquisition device may acquire images of one or more portions (e.g., sputter-deposited surface) of the substrate108. As described herein, in some embodiments, the acquired images may be processed and stored locally on the measurement device164or remotely from the measurement device164. Measurements of portions of the substrate may be obtained from the processed images.

At206, the processed images may be analyzed by the analysis device166to detect one or more defects of the substrate108. For example, the analysis device166may inspecting the processed images for the presence of one or more defects of the substrate. In some embodiments, the processed images may be inspected for the presence and clarity of an alignment mark on the substrate. As discussed above, in some embodiments, the measurements may be compared to predetermined thresholds to determine whether one or more defects are present. For example, a defect may be determined to be present if an alignment mark is not visibly present or is measurably unclear. Also, in some embodiments, the analysis device166may use any type of image analysis techniques, including use of optical recognition and/or artificial intelligence to identify features and defects on the substrate108. Also, for each defect detected, one or more zone of the plurality of zones109corresponding to the location of the defect may be determined.

At208, if the analysis device166determines that a defect is present on the substrate108(e.g., an alignment mark at an edge of the substrate has become blurry), a feedback signal may be sent to the temperature controller126at210to the temperature control system111to modify a temperature control parameter of a temperature controller used in controlling a temperature of the substrate in the deposition process. For example, the temperature control parameter may include temperature setpoints of the one or more zones of the plurality of zones109that are determined to correspond to the detected defect. Also, as discussed above, the temperature control parameter may include tuning parameters for the driver128of the temperature controller126. Also, at210, after the substrate108has been measured in the measurement chamber162, the substrate108may be transferred out of the measurement chamber162(e.g., to another chamber of the cluster tool180) to make room in the measurement chamber162to measure another substrate that has been processed in process chamber102.

At212the temperature controller126may respond to the feedback signal by adjusting the temperature control system111, such as by adjusting temperature setpoints for one or more zones109or tuning the output of the driver128. The method200may then repeat202-212for multiple different substrates processed in the process chamber102until no defect is found at208.

At208, if the analysis device166determines that no defect is present on the substrate108, the method200may end at214, whereupon any substrate108in the measurement chamber162may be transferred out of the measurement chamber162(e.g., to another chamber of the cluster tool180).

The method200may be performed multiple times, such as periodically, or on demand as deemed desirable to maintain process control of deposition processing in the process chamber102.

The embodiments of the methods, systems, and apparatus described herein can provide substrate temperature control based on defects detected in a processed substrate. By sending feedback signals to the temperature controller126, temperature control of substrates undergoing processing in the process chamber102can compensate for the effects of AC bias induced surface degradation and electrostatic chuck contamination, thereby reducing defects and improving yield.