In-situ temperature mapping for epi chamber

The present invention provides methods and apparatus for processing semiconductor substrates in an epitaxy chamber configured to map a temperature profile for both substrates and interior chamber components. In one embodiment, the semiconductor processing chamber has a body having ceiling and a lower portion defining an interior volume. A substrate support is disposed in the interior volume. A mounting plate is coupled to the ceiling outside the interior volume. A movement assembly is coupled to the mounting plate. A sensor is coupled to the movement assembly and moveable relative to the ceiling. The sensor is configured to detect a temperature location in the interior volume.

BACKGROUND

Field

The present disclosure relates to apparatus and method for mapping temperatures in a processing chamber. More particularly, the present invention relates to apparatus and method in-situ temperature mapping of substrates in an epitaxy processing chamber.

Description of the Related Art

Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and micro devices. Varieties of semiconductor processing systems and/or chambers are utilized to perform a variety of operations/methods in the formation of the devices on the semiconductor substrates. One method of processing substrates includes etching material on an upper surface of a substrate. Another method of processing substrates includes depositing a material, such as a semiconductor material or a conductive material, on the upper surface of the substrate.

Epitaxy is one example of a deposition process that deposits films of various materials on a surface of a substrate in a processing chamber. Epitaxy processes are able to produce such high-quality films on substrates under certain process conditions, such as temperature, pressures, and precursor flow rates, within the processing chambers. Any variations in process parameters such as temperature, pressure and precursor flows result in film thickness and profile's variation. During the deposition process, non-uniform gas flow, heat flow/transmission, or dopant gas concentration across the substrate surface may undesirably result in the resultant silicon epitaxial layer having different film properties at different locations. For example, sheet resistance as measured at an edge of the silicon epitaxial layer may be different from that measured at the center, as heat or process precursor gas may not be distributed uniformly across the substrate surface. In some cases, fluctuation of sheet resistance at different locations of the substrate surface may be significant, which may undesirably create device performance reliability issues, and even damage product yield.

To monitor various process conditions, sensors are used to determine the temperature of specific chamber components with each sensor measuring a specific location and thus a single component. Thus, multiple sensors are required to measure more than a single chamber component in addition to the substrate during processing. All of the sensor combine to provide feedback for properly processing the substrate.

Therefore, there is a need for apparatus and methods to monitor and control temperature of the substrate to ensure uniformity and identify potential issues related to wafer heating mechanism or wafer placement before the deposition step starts.

SUMMARY

The present invention provides methods and apparatus for processing semiconductor substrates in an epitaxy chamber configured to map a temperature profile for both substrates and interior chamber components. In one embodiment, the semiconductor processing chamber has a body having ceiling and a lower portion defining an interior volume. A substrate support is disposed in the interior volume. A mounting plate is coupled to the ceiling outside the interior volume. A movement assembly is coupled to the mounting plate. A sensor is coupled to the movement assembly and moveable relative to the ceiling. The sensor is configured to detect a temperature location in the interior volume.

In another embodiment, a sensor assembly for an epitaxy processing chamber is disclosed. The sensor assembly has a sensor coupled to movement assembly mounted outside of the epitaxy processing chamber. The sensor is configured to detect a temperature at a location disposed within an interior volume of the epitaxy processing chamber, wherein movement assembly is operable to direct the sensor to the location within the interior volume for temperature sensing.

In yet another embodiment, a method for mapping the temperature of a substrate in a processing chamber is disclosed. The method begins by placing a substrate on a substrate support assembly within a processing chamber, wherein the processing chamber has a ceiling disposed above the substrate support. The temperature of the substrate is detected with a sensor disposed above the ceiling of the processing chamber. The sensor is moveable relative to the ceiling to traverse the substrate with a plurality of temperature readings. A temperature map of the substrate is generated with the plurality of temperature readings.

DETAILED DESCRIPTION

For film deposition, e.g., in an epitaxy chamber, a substrate support assembly is often used to support the substrate as well as heat the substrate during processing. The substrate is heated by absorbing radiation from lamps positioned outside of the epitaxy chamber. The substrate support assembly and substrate are rotated to minimize temperature non-uniformities resulting from the direct radiation of the lamps. Ideally, the rotation makes the temperature profile axisymmetric. As discussed below, an articulating sensor is disclosed to provide real-time operational feedback for process parameters of the processing chamber. For example, a sensor measures the temperature of a substrate across a number of locations to assist in maintaining optimum processing conditions as well as identify potential issues, which may result in an asymmetric thermal profile on the substrate if not corrected. For example, the temperature sensor can detect temperature disparities on the substrate that are indicative of the substrate being out of the pocket (i.e., not properly seated and centered on the substrate support assembly). Additionally, the temperature sensor can be utilized to confirm the integrity of the process temperature across the whole substrate surface and other components of the epitaxy chamber.

At least two methods for measuring the temperature profile across the substrate are enabled through the use of an articulating sensor. In one example, a radial scanning pyrometer is utilized as the sensor. The pyrometer analyzes a wavelength at which Si is opaque and quartz is transparent (e.g., 2.4 um) and moves on a linear, arcing or rotating stage. The wafer pyrometer can be directed (e.g., articulated) to scan along the radius extending from the chamber body and ending at the center of the substrate. The scanned IR signal obtained by the wafer pyrometer, correlated with the rotational speed of the substrate support assembly, is logged as a function of radius. The radial scanning pyrometer may additionally be used for tuning chamber parameters to enable the real time thermal uniformity monitoring/control, or run to run control using a mapping feedback of measured temperature locations versus desired temperatures for the same locations in the processing chamber. The apparatus is also suitable for establishing a reference for chamber setup and chamber to chamber matching. In some embodiments, one or multiple sensors, e.g. thermometers or thermal cameras, can be mounted on a linear or curved motion controlled stage spanning across a top of the processing chamber. The sensor is suitable to monitor temperatures at the very edge of the chamber and the substrate which is not practical with current large spot pyrometers.

Signals collected from the sensor are logged as a function of polar coordinates on the process plane. The process plane can include preheat ring, substrate support assembly edge, as well as the substrate or even a chamber liner. Depending on the resolution required (e.g. n=49 sampling points (e.g., locations)) and the rotational speed of the substrate support assembly (ω), the speed of the stage (Vs) may be adjusted to collect the required number of data points in scanning the radius of the process plane in “m” complete rotations of substrate. The measurement can be repeated, if needed or desired, and an average of the data can be processed. If an equal distance temperature profile of the substrate in radial direction is desired, a variable speed on the linear (or curved) stage may be used. Alternatively, a variable rotational speed of the substrate support assembly can provide similar outcome for determining the equal distance temperature profile of substrate.

The mapping of the temperature of the substrate can be axisymmetric mapping in the two dimensional (2D) plane or in three dimensions (3D).

The sensor is mounted to a stage. In one example, the sensor is fixed mounted to the stage. In another example, the sensor is gimbal and/or rotationally mounted to a stage. The stage may offer additional movement to the sensor. For example, the sensor is mounted to a stage having a linear travel. In another example, the sensor is mounted to a stage rotated to target different spots across the process plane. In a yet another example, a combination of linear and rotational motion of the stage mounted sensor may be implemented to enhance the reach of the detection inside the chamber.

FIG. 1schematically illustrates a sectional view of one embodiment of an epitaxy process chamber100in accordance with embodiments of the present invention. In one embodiment, an epitaxy processing chamber100that may be adapted to benefit from the invention is an EPI CENTURA® near atmospheric chemical vapor deposition (CVD) System, available from Applied Materials, Inc., of Santa Clara, Calif. The epitaxy processing chamber100presented herein shown in schematic is one embodiment and is not intended to be limiting of all possible embodiments. It is envisioned that other substrate processing chambers can be used in accordance with embodiments described herein, including chambers from other manufacturers.

The epitaxy chamber100comprises a chamber body101, support system104, and a chamber controller106. The chamber body101includes the upper reflector module102and the lower lamp module103. The upper reflector module102includes the area within the chamber body101between a ceiling116and a substrate support assembly132disposed within the chamber body101. The ceiling116may be formed from a transparent quartz or other suitable material. In one example, the ceiling116may be an upper dome. The epitaxy chamber100additionally has an articulating sensor assembly200. The articulating sensor assembly200is coupled to the epitaxy chamber100. In one example, the articulating sensor assembly200is to a mounting plate190that is attached to the ceiling116. The mounting plate190may additionally be a reflector. The mounting plate190reflects back the energy to the substrate and may have openings only where the articulating sensor assembly200needs to have line of sight to the process volume. Alternately, articulating sensor assembly200may be attached directly to the ceiling116.

The lower lamp module103includes the area within the chamber body101between a lower portion130of the chamber body101and the substrate support assembly132. In one example, the lower portion130may be a lower dome. Deposition processes generally occur on an upper surface of a substrate125supported on the substrate support assembly132and exposed to the upper reflector module102. The substrate125is supported by support pins121disposed beneath the substrate125and extending from the substrate support assembly132.

An upper liner118is disposed within the upper reflector module102and is adapted to prevent undesired deposition onto chamber components. The upper liner118is positioned adjacent to a ring123within the upper reflector module102. The ring123(explain what is does).

The epitaxy chamber100includes a plurality of heat sources, such as lamps135, which are adapted to provide thermal energy to components positioned within the epitaxy chamber100. For example, the lamps135may be adapted to provide thermal energy to the substrate125and the ring123. The lower portion130may be formed from an optically transparent material, such as quartz, to facilitate the passage of thermal radiation therethrough.

The chamber body101also includes an outer inlet port198formed through a sidewall of the chamber body101and a central inlet port152formed on a center region of the upper dome where a center gas line154is coupled to. An outer gas line (not shown) and an inner gas line111may be coupled to the outer inlet port198and the central inlet port152respectively to deliver gases supplied from a gas panel module107. An exhaust port127may be coupled to the chamber body101to maintain the epitaxy chamber100at a desired regulated pressure range as needed. The outer inlet port198may be adapted to provide a gas, including doping gas, reacting gas, non-reacting gas, inert gas, or any suitable gas therethrough into the upper reflector module102of the chamber body101. Thermal decomposition of the gas onto the substrate125configured to form an epitaxial layer on the substrate125is facilitated by the lamps135.

The substrate support assembly132is positioned in the lower lamp module103of the chamber body101. The substrate support assembly132is illustrated supporting a substrate125in a processing position. The substrate support assembly132includes a plurality of support pins121and a plurality of lift pins133. The lift pins133are vertically moveable and are adapted to contact the underside of the substrate125to lift the substrate125from a processing position (as shown) to a substrate transfer position. The components of the substrate support assembly132can be fabricated from quartz, silicon carbide, graphite coated with silicon carbide or other suitable materials.

The ring123is removably disposed on a lower liner140that is coupled to the chamber body101. The ring123is disposed around the internal volume of the chamber body101and circumscribes the substrate125while the substrate125is in the processing position. The ring123can be formed from a thermally-stable material such as silicon carbide, quartz or graphite coated with silicon carbide. The ring123, in combination with the position of the substrate125, separates the volume of the upper reflector module102from the lower lamp module103. The ring123directs gas flow through the upper reflector module102when the substrate125is positioned level with the ring123. The separate volume of the upper reflector module102enhances deposition uniformity by controlling the flow of process gas as the process gas is provided to the epitaxy chamber100.

The support system104includes components used to execute and monitor pre-determined processes, such as the growth of epitaxial films in the epitaxy chamber100. The support system104includes one or more of the gas panel modules107, gas distribution conduits, power supplies, and process control instruments. A chamber controller106is coupled to the support system104and is adapted to control the epitaxy chamber100and support system104. The chamber controller106includes a central processing unit (CPU), a memory, and support circuits. Instructions resident in chamber controller106may be executed to control the operation of the epitaxy chamber100. The epitaxy chamber100is adapted to perform one or more film formation or deposition processes therein. For example, a silicon epitaxial growth process may be performed within the epitaxy chamber100. It is contemplated that other processes may be performed within the epitaxy chamber100.

During film deposition in the epitaxy chamber100, the substrate125is heated. The substrate125is heated by absorbing radiation from the lamps135. The substrate support assembly132and substrate125are rotated to minimize temperature non-uniformities resulted from the direct radiation of the lamps135.

The articulating sensor assembly200provides real-time operational feedback for process parameters in the epitaxy chamber100utilizing temperature sensing. The articulating sensor assembly200has one or more sensors201,202configured to provide temperature information which can be moved into an orientation that enables detecting temperature at a selected location within the epitaxy chamber100. For example, articulating sensor assembly200is operable to move the one or more sensors201,202into an orientation that enables temperature to be sensed for one or more of the upper liner118, the ring123, the lower portion130, the ceiling116, the substrate125, the substrate support assembly132or other internal chamber component. In one example, the sensor201measures the temperature of the substrate125to assist in maintaining optimum processing conditions as well as identify potential issues, which may result in an asymmetric thermal profile on the substrate125. For example, the sensor201can detect when the substrate125is not properly positioned on substrate support assembly132and confirm the integrity of the process temperature across the whole surface of the substrate125. The articulating sensor assembly200may be configured to move the sensor201in a linear fashion and/or rotate the sensor201.

FIG. 2Ais a side view schematically illustrating the mounting plate190with one embodiment of the articulating sensor assembly200suitable for use in the epitaxy process chamber100ofFIG. 1. A reflector292is attached to the mounting plate190and shown figuratively to encompass the bounded area of the upper reflector module102. In some example, the mounting plate190is a reflector and reflector292is part of the mounting plate190. Similarly, the substrate support assembly132is illustrated as a solid body when the substrate support assembly132may be either solid as shown inFIG. 2Aor hollow as shown inFIG. 1. The operation of the articulating sensor assembly200is not limited by the configuration of the epitaxy process chamber100, or other processing chambers.

The articulating sensor assembly200includes a stage290to which the sensor201is attached. The stage290is disposed on a linear rail210. The linear rail210may be a track, or other suitable mechanism for ensuring linear movement of the stage290attached to the linear rail210. A movement assembly260may control the stage location along the linear rail210. The movement assembly260may be a linear motor, a servo motor, stepper motor, pneumatic cylinder, hydraulic cylinder, or other type of actuator suitable for creating movement of the stage290along the linear rail210. In this manner, movement of the stage290can be precisely limited to the length and direction of the linear rail210. Thus, the sensor201disposed in stage290moves relative to the mounting plate190and the ceiling116. The linear rail210may have a length284sufficient to move the stage290from a center280of the epitaxy process chamber100to the reflector292.

A window294is formed in the mounting plate190and/or the reflector above the ceiling116. Turning briefly toFIG. 4,FIG. 4is a top view schematically illustrating the window294in the mounting plate190of the epitaxy process chamber100. The sensor201is configured to move with the stage290and while maintaining alignment with the window294such that the sensor201may detect temperatures within the epitaxy process chamber100while moving along with the state290. The window294may be formed from quartz or other material transparent to the sensing signal of the sensor201.

The sensor201is configured to detect a temperature at a selected location in the interior volume of the epitaxy process chamber100. The sensor201may be a pyrometer, camera, or other suitable device for measuring temperature. In one example, the sensor201is a camera operating at a wavelength of between about 8 um to about 14 um. In one example, the sensor201is a pyrometer operating at a wavelength such as 2.4 um where the quartz material in the window294is transparent, i.e., less than about 4 um. The wavelength of the sensor201may be modified or changed to measure temperature of the ceiling116below the window294. The sensor201may be fixed to the stage290such that the orientation of the sensor201relative to the mounting plate190is unchanged as the sensor201moves along the linear rail210. The sensor201emits a sensing beam250that is directed through the window294into the epitaxy process chamber100. The sensing beam250may be moved from the center282the outer limits, i.e., reflector292, of the epitaxy process chamber100for measuring parameters of the epitaxy process chamber100or the substrate125disposed within the epitaxy process chamber100.

FIG. 2Bis a top view schematically illustrating a view path240of the sensor201along a top surface225of the substrate125disposed in the epitaxy process chamber100. The view path240is created by the sensing beam250emitted by the sensor201traversing over the top surface225of the substrate125. The substrate125is rotated at an angular velocity (ω) by a rotation232of the substrate support assembly132. The combination of the rotation232of the substrate support assembly132and a linear velocity211of the sensor201along the linear rail210may be adjusted in forming a variety of different view path240. For example, the sensor201may extend along first radius284project the beam250on a first sample location241. The combination of rotation232and linear velocity211and a sample interval connect together in forming the view path240. For example the first sample location241, a second sample location242, ⅓ sample location243, fourth sample location244, a fifth sample location245, a sixth sample location246, and a seventh sample location247all combine in the formation of view path240. It should be appreciated that if an equal distance in a radial direction is needed the linear velocity211may be set to zero, i.e., no movement, while the rotation232is performed. In the manner described above an asymmetric mapping or actual 3D map can be generated which illustrate the temperature of the substrate125.

It should also be appreciated, that the beam250can be focused on the substrate support assembly132while the substrate125is not present to determine the temperature of the substrate support assembly132. Likewise, the beam250can be focused past the substrate support assembly in determining a temperature of the lower dome114or other chamber component. Additionally can be shown, by sampling at an equal distance in a radial direction along the outer perimeter of the substrate125, that it can be determined if the substrate125is outside the pocket of the substrate support assembly132. For example, the temperature profile of the substrate125along the outer edge may show a cold or hot arc where the substrate support assembly132is actually being sampled by the beam250instead of the expected substrate125.

FIG. 3Ais a side view schematically illustrating the mounting plate190with another embodiment of the articulating sensor assembly200that may be utilized in the epitaxy process chamber100ofFIG. 1. The epitaxy process chamber100is substantially similar to that discussed above with respect toFIG. 1andFIG. 2A. The articulating sensor assembly200has the sensor201attached to a stage300.

FIG. 3Bis a side view schematically illustrating the stage300coupled to the sensor201. The stage300may be fixed, i.e., non-moveable, or have a rotational bracket310. The stage300has a base312and an upright support314. The sensor201may be fixed or movably attached to the upright support314. For example, the sensor201may be attached to the to the upright support314by a pivot370extending through the upright support314. The pivot370may be fixedly attached to the sensor201such that rotation of the pivot370will rotate the sensor201, which in turn orientates the sensor201to enable temperature information to be obtained from different locations within the epitaxy process chamber100. Alternately, the pivot370may freely extend through the sensor201such that the sensor201may be rotated about the pivot370and independent of rotation of the pivot370. For example, the pivot370may be a smooth rod which fits through an oversized whole in the sensor201such as the sensor201may move independently of the smooth rod.

The sensor201may be moved about one or more axis of rotation. For example the sensor201may rotate (as shown by arrow372) along a centerline380orthogonal to the mounting plate190. Additionally, or alternately, the sensor201may rotate (as shown by arrow374) along the pivot370extending parallel to the mounting plate190. One or more movement assembly260may provide the rotation, as depicted by arrow372and/or arrow374, for directing a beam350of the sensor201to different selected locations within the epitaxy process chamber100.

In one example, the sensor201rotates about the pivot370and the stage300is stationary. The rotation of the sensor201about the pivot370is controlled by the movement assembly260. The movement assembly260may be a cylinder, motor or other actuator suitable for moving either the pivot370and sensor201together, or or moving the sensor201about the pivot370. The base312may have a slot or other feature which prevents interruption of the beam350as the beam350is directed into the epitaxy process chamber100. In another example, the base312may be formed from a quartz material transparent to beam350. Thus, as the sensor201rotates about the pivot370, the beam350is controllably directed form the center280to the reflectors292. As the substrate support assembly132rotates the substrate125, the beam350pivoting through an angle386traverses a length384linearly along the substrate125such that temperature information across the entire substrate125may be obtained utilizing a single sensor201. This configuration allows for a beam path similar to what is shown and described inFIG. 2B.

In another example, the sensor201is fixed about the pivot370and the stage300is rotatable by way of the rotational bracket310. Turning briefly again toFIG. 4,FIG. 4schematically illustrates a window295in the mounting plate190of the epitaxy process chamber100ofFIG. 1. The window295is curved to match the rotation of the sensor201on the rotational bracket310. The movement assembly260may be part of the rotational bracket310, or alternatively mounted to the mounting plate190or the stage300to rotate the rotational bracket310. The rotational bracket310may move through about 180° to about 360° of rotation. The rotational movement of the sensor201coupled with the rotation of the substrate support assembly125results in orienting the beam across a path that scans the entire surface of the substrate125for mapping the temperature of the substrate. Rotation of the sensor201at the extremes, i.e., near 180° and 0°, may move the sensor beam350off the substrate125for measuring temperatures of chamber components such as the lower portion130of the epitaxy chamber100, among others.

In yet another example, the sensor201may rotate about the pivot370while also being rotated by the rotational bracket310. These two axes of rotation allows for the beam350to be directed in a manner that increases the locations in which temperature may be sensed by the sensor201. Thus, processing conditions in the epitaxy chamber environment can be more closely monitored and maintained. Through controlling of the movement of the beam350along with the movement of the substrate support assembly132, a comprehensive mapping for the temperature along the top of the substrate125and substrate support assembly132can be obtained. The comprehensive mapping enables more precise control over the epitaxial process.

In yet another example the sensor201may rotate about the pivot370, rotate by the rotational bracket310, and linearly travel along the linear rail210. Such an arrangement allows for the sensor201to reach and detect temperatures of nearly all surfaces in the interior volume of the epitaxy chamber100, such as the upper liner118, the ring123, the lower portion130, the ceiling116, the substrate125, the substrate support assembly132or other internal chamber component.

FIG. 5is a flow diagram for a method500for mapping the temperature of a substrate in a processing chamber. The method500begins at operation510by placing a substrate on a substrate support assembly within an epitaxy process chamber. The epitaxy process chamber has an upper dome enclosing an interior volume and the upper dome is disposed above the substrate support assembly. In one example, the epitaxy process chamber is as described with respect to the Figures above.

At operation520, the temperature of the substrate is detected using an articulating sensor disposed above the upper dome of the processing chamber. In one example, the sensor is a pyrometer. In another example, the sensor is a camera.

At operation530, the sensor is moved relative to the upper dome to obtain a plurality of temperature readings across the surface of the substrate. The sensor may linearly move along a linear rail coupled to the lid. Alternately, or additionally, the sensor is coupled to a rotating and/or linearly movable stage supporting the sensor and the stage is coupled to the lid. In other alternatives, or additions to prior examples, the sensor may be pivoted on a stage supporting the sensor.

At operation540, a temperature map of the substrate is generated utilizing the plurality of temperature readings. The temperature map be of a substrate disposed in the epitaxy processing chamber. The temperature map may additionally or alternatively be of chamber components which may be utilized for monitoring the health of the epitaxy processing chamber. The temperature map may be indicative of process skew. The temperature map may additionally provide an indication of a fault condition such as the substrate being miss positioned on the substrate support assembly. The temperature map may include calculated and/or measured temperature locations. In one example, a computer having a processor and memory may run a software routine that takes as input the measured temperatures locations and interpolate between the locations to provide calculated temperatures in formation of the temperature map. The temperature map may be compared to acceptable ranges of temperatures for one or more location on the temperature map. A message may be sent in response to a determination that the temperature map has sampled or calculated temperature at one or more locations that are outside of acceptable ranges.

The 3D map constructed by the disclosed invention can further be used in conjunction with a supervised or unsupervised machine learning algorithm where some of the fault scenarios are automatically identified and notification issued to the user. For example, a set of cases where the substrate is out of susceptor pocket can be mapped and the set can be used to train the algorithm. In another example, anomalous temperature of other parts in the chamber, such as susceptor, preheat-ring, upper or lower dome may also be identified by an artificial intelligence and machine learning algorithm which is trained by intentionally engineered faults such as issues with lamps, dome coating, cracks, or susceptor coating degradation. Each of these training sets can be used to augment the algorithm to intelligently identify the issue and either notify the user immediately or depending on the severity of the issue automatically schedule for relevant inspection and/or maintenance procedure during next planned maintenance.

Advantageously, in the examples described above, the sensor201is movable relative to the ceiling116and able to precisely monitor processing conditions such as temperature skew as well as potential error conditions such as substrates125not properly situated on the substrate support assembly132. Thus, a single sensor can replace a multitude of sensors while providing a greater benefit and understanding of processing conditions for reducing defects on the substrates.