Patent Publication Number: US-2022214225-A1

Title: Temperature detector probe with thermal isolation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/360,669 filed Mar. 21, 2019, which claims the benefit of and priority to U.S. Provisional Application No. 62/647,094 filed on Mar. 23, 2018. The content of the above applications are incorporated herein by reference in their entirety. 
    
    
     FIELD 
     The present invention relates to a surface temperature sensor device that detects a temperature of a surface. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Surface temperature detectors are designed to be close to or even contact a surface to measure the temperature of the surface. Such temperature detectors are used to provide temperature measurements in temperature sensitive processes. For example, semiconductor processes depend on accurate temperature measurements to control the temperature of various components within a processing chambers, such as chuck/pedestal used for forming semiconductor wafers. 
     Typically, a surface temperature detector includes a thermal sensing device, such as a resistive temperature device, that is positioned in a housing. The accuracy of the thermal sensing device varies based on, for example, the thermal conductivity between the housing and the sensing device, the position of the thermal sensing device relative to the surface being measured, the material properties of the thermal sensing device, and other factors. These and other issues are addressed the teachings of the present disclosure. 
     SUMMARY 
     This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features. 
     The present disclosure is directed toward a temperature detector probe that includes a housing, a pair of electrical connectors, a support cap, and a sensor. The housing defines a bore extending longitudinally through the housing. The pair of electrical connectors extend longitudinally through the bore. The support cap is disposed at a first end portion of the housing, and the sensor is provided on the support cap and electrically coupled to the pair of electrical connectors. The support cap is positioned between the pair of electrical connectors and the sensor. 
     In one form, the temperature detector probe further includes a pair of electrical pins extending through a second end portion of the housing and electrically coupled to the pair of electrical connectors. 
     In another form, the pair of electrical connectors are POGO pins that are electrically coupled to the sensor via the support cap. 
     In yet another form, the pair of electrical connectors are a pair of wires that are electrically coupled to the sensor via the support cap. 
     In one form, the support cap is made of polyamide. 
     In another form, the support cap includes two plated through-holes to electrically couple the pair of electrical connectors and the sensor. 
     In yet another form, the sensor is a resistance temperature detector sensor chip. 
     In one form, the sensor is a thin film resistive element deposited on the support cap, and the thin film resistive element has a high temperature coefficient of resistance. In one variation, the thin film resistive element is one of copper, nickel, nickel-iron, or platinum. 
     In another form, the temperature detector probe further includes a temperature insulating material disposed on a surface of the sensor. 
     In yet another form, the sensor is configured to directly contact a surface of an object to measure a temperature of the object. 
     In one form, the housing defines one or more circumferential grooves along an exterior of the housing. 
     In another form, the sensor is a thermocouple. 
     In one form, the temperature detector probe further includes a signal processing circuit that is communicably coupled to the sensor to condition a signal from the sensor. In one variation, the housing defines a chamber at a second end portion of the housing, and the signal processing circuit is disposed at the chamber. The pair of electrical connectors are electrically coupled to the signal processing circuit to communicably couple the sensor and the signal processing circuit. 
     In another form, the present disclosure is directed toward a system comprising an object, and the temperature detector probe of the present disclosure. The temperature detector probe is disposed in the object, and the sensor of the temperature detector probe directly faces the surface of the object. 
     In one form, the present disclosure is directed toward a temperature detector probe that includes a housing, a pair of electrical connectors, a support cap, and a sensor. The housing defines a bore extending longitudinally through the housing. The housing has one or more circumferential grooves along an exterior of the housing. The pair of electrical connectors extend longitudinally through the bore. The support cap is disposed at a first end portion of the housing. The support cap includes a first surface facing the bore and a second surface exposed to environment. The sensor generates a signal indicative of a temperature. The sensor is electrically coupled to the pair of electrical connectors, and is disposed on the second surface of the support cap away from the bore. 
     In yet another form, the temperature detector probe further includes a pair of electrical pins extending through a second end portion of the housing. The pair of electrical connectors are a pair of wires that are electrically coupled to the pair of electrical pins and to the sensor via the support cap. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG. 1  is a partial cross-sectional view of an object with a temperature detector probe in a first form in accordance with the teachings of the present disclosure; 
         FIG. 2  is a perspective view of the temperature detector probe of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the temperature detector probe of  FIG. 2 ; 
         FIG. 4A  is a cross-sectional view of a temperature detector probe in a second form in accordance with the teachings of the present disclosure; 
         FIG. 4B  is a front view of the support cap and the sensor for the temperature detector probe of  FIG. 4A ; 
         FIG. 5  is a partial cross-sectional of a temperature detector probe in a third form in accordance with the teachings of the present disclosure; 
         FIG. 6  is a partial cross-sectional of a temperature detector probe in a fourth form in accordance with the teachings of the present disclosure; and 
         FIG. 7  is a partial cross-sectional of a temperature detector probe in a fifth form in accordance with the teachings of the present disclosure. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     The present disclosure is directed toward a temperature detector probe that reduces or inhibits thermal conductivity between the probe and an object, and also reduces thermal shunting of the temperature measurement. More particularly, as described herein, the temperature detector probe includes a housing that has grooves circumferentially extending along its exterior at a portion of the probe closest to the surface being measured. The grooves may form a thermal breaker to reduce the transfer of heat between the object and the probe. In addition, the probe includes a sensor that is disposed outside of the housing and is positioned in proximity of or in some forms, directly contacting the surface being measured. This arrangement may improve the response time of the sensor while minimizing thermal shunting. It should be readily understood that the temperature detector probe of the present disclosure addresses other issues, and should not be limited to the examples provided herein. 
     Referring to  FIG. 1  a temperature detector probe  100 , which may also be referred to as a sensor device, is operable to detect the temperature of an object  102 , and more particularly, a surface  104  of the object  102 . The object  102  may be, for example, a chuck or pedestal used for processing semiconductor wafers. However, the temperature detector probe  100  may be used to detect the temperature of other objects and should not be limited to the examples provided herein. 
     In one form, the temperature detector probe  100  extends through the object  102  up to the surface  104 . In one form, a gap  106  is provided between the temperature detector probe  100  and the object  102  to reduce thermal conductivity between the object  102  and the probe  100 . The size of the gap can vary based on the application. 
     Referring to  FIGS. 2 and 3 , in one form, the probe  100  includes a housing  110 , one or more electrical connectors  112  (i.e.,  112   1  and  112   2 ), a support cap  114 , and a sensor  116 . The housing  110  has a first end portion  120  and a second end portion  122 , and defines a bore  124  that extends longitudinally through the housing  110  between the first end portion  120  and the second end portion  122 . In one form, a cap  125  is provided at the first end portion  120  to prevent foreign matter from entering the probe  100 . The housing  110  may be viewed as having an extension portion  130 , which includes the first end portion  120 , and a sensor portion  132 , which includes the second end portion  122 . When located within the object  102 , the sensor portion  132  is positioned closer to the surface  104  of the object  102  than the extension portion  130 . In one form, the sensor portion  132  of the housing  110  includes one or more thermal breaks  134  provided as circumferential grooves defined along an exterior of the housing  110  to inhibit thermal conductivity between the object  102  and the probe  100 , and between the extension portion  130  and the sensor portion  132 . In one form, the thermal breaks  134  extend through the housing  110 , and in another form, a thin wall of the housing  110  is provided between the thermal breaks  134  and the bore  124 . The housing  110  may be made of plastic, such high-performance polyimide-based plastics, such as polyether ether ketone, or other suitable material. 
     The electrical connectors  112  extend through the bore  124  to the second end portion  122  of the sensor portion  132 . The electrical connectors  112  are configured to electrically couple and thus, communicably couple the sensor  116  to a control system (not shown) that receives signals indicative of the surface temperature of the object. In one example application, the control system is configured to control a heater, such as a pedestal heater. The control system receives the signals from the probe  100 , and controls power to the heater system based on the signal and other inputs. This is just one example application. 
     The electrical connectors  112  extend longitudinally through the bore  124  and are electrically coupled to the sensor  116 . In one form, the electrical connectors  112  are a pair of pins, such as a pair of POGO pins, and each pin includes a lead portion  140  (i.e.,  140   1  and  140   2 ) and a pin portion  142  (i.e.,  142   1  and  142   2 ). The lead portion  140  extends through the first end portion  120  and is configured to electrically couple to a control system via a cable/wire connection. The pin portion  142  extends from the lead portion  140  to the second end portion  122  and is electrically coupled to the sensor  116 . The electrical connectors may be configured in other suitable ways, an example of which is provided below. 
     The support cap  114  is located at the second end portion  122 , and is configured to align and support the sensor  116  with the surface  104  of the object  102 . In one form, the support cap  114  has a disk like shape and is made of a low thermal conductive material, such as polyamide, to inhibit thermal conductivity between the sensor  116  and the housing  110 . Other materials may include elastomeric materials such as polydimethylsiloxanes. The support cap  114  includes a first surface that faces the bore  124  and a second surface that is exposed to the environment. The support cap  114  is configured in various suitable ways based on the size of the sensor  116  and packaging size of the probe  100 . For example, in one form, the thickness of the support cap  114  is approximately 0.001 to 0.005 inch. The support cap  114  is also configured to electrically couple the sensor  116  to the electrical connectors  112 . In one form, with the sensor  116  being a surface mount device, the support cap  114  includes plated through holes  144  (i.e.,  144   1  and  144   2 ) that electrically couple to solder pads of the sensor  116  and to the electrical connectors  112 . Other suitable methods for electrically coupling the sensor  116  to the electrically connectors  112  via the support cap  114  may also be used while remaining within the scope of the present disclosure. 
     The sensor  116  is operable to measure a temperature of the surface  104 , and outputs a signal indicative of the temperature to the control system. In one form, the sensor  116  is a resistance temperature detector (RTD) type sensor that is located on the support cap  114 , and more particularly, along a second surface of the support cap  114 . In  FIG. 3 , the sensor  116  is provided as a RTD surface mount device that generally includes a case and a resistive element having a high temperature coefficient of resistance (TCR) disposed within the case. For example, the resistive element may be, but is not limited to, copper, nickel, nickel-iron, or platinum. The RTD surface mount device is mounted to the support cap  114  via reflow solder. In one example implementation, the RTD surface mount device follows an industry standard 0603 size (0.8×1.6 mm) for surface mount devices, and has a 0.45 mm thickness and has a mass of 1.9 mg. In another form, the sensor  116  is a thermocouple mounted to the surface of the support cap  114 . 
     Based on the application, the sensor  116  is configured to directly contact or be in proximity to the surface  104  of the object  102  to measure a temperature of the surface  104 . In one form, the support cap  114  has resilient or elastic qualities, such that the position of sensor  116  is flexible to contact the surface  104  of the object  102 . In addition, with the electrical connectors  112  being POGO pins, the pins provide a biasing force against the support cap  114  and the sensor  116  to have the sensor  116  contact the surface  104 . 
     In operation, the probe  100  is positioned in the object  102 , and is electrically coupled to the control system by way of the electrical connectors  112  and wires. The sensor  116  may be in direct contact with or is proximity to the surface  104  to measure the temperature of the surface  104 . The control system is communicably coupled to the sensor  116 , and receives a signal that is indicative of temperature from the sensor  116 . 
     By way of the support cap  114  and the housing  110  having the grooves, the thermal conductivity between probe  100  and the object and between the sensor  116  and the housing  110  is reduced or inhibited to potentially improve, for example, accuracy, response time, and offset errors of the sensor. 
       FIGS. 4A and 4B  illustrate another variation of a temperature detector probe that has different electrical connectors and sensor. Specifically, in one form, a temperature detector probe  200  includes the housing  110 , a pair of electrical pins or leads  202  (i.e.,  202   1  and  202   2 ), a pair of electrical connectors  204  (i.e.,  204   1  and  204   2 ), a support cap  206 , and a sensor  208 . The electrical leads  202  are operable to electrically couple the probe  200  to the control system, and extend through the first end portion  120  of the housing  110 . The probe  200  further includes a cap  210  disposed at the first end portion  120  to prevent foreign material from entering the housing  110 . 
     The electrical connectors  204  are wires that are connected to the leads  202 , for example, solder or spot welding, and may be referred to as wires  204 . In one form, the electrical connectors  204  are small gauge wires, such as 36 to 40 gauge. Like the electrical connectors  112  of probe  100 , the wires  204  extend through the bore  124  and are electrically coupled to the sensor  208  via the support cap  206 . 
     In one form, the sensor  208  is a resistive element  210  having a high TCR that is deposited on the support cap  206 . That is, in lieu of mounting a case having the resistive material disposed therein, the probe  200  provides the resistive material directly on the support cap  206 . Accordingly, when disposed in the object, the resistive material is directly in contact with or in close proximity to the surface of the object, and thus, may increase the response time of the sensor  208  and reduce thermal shunting. 
     In one form, the support cap  206  is a rigid disk of low thermal expansion material such as quartz, silicon, aluminum oxide (Al2O3), aluminum nitride (AlN). In another form, the support cap  206  is made of a metal substrate such as stainless steel or Invar coated with a dielectric to insulate the resistive element (i.e. sensor  208 ) from the substrate. Similar to the probe  100 , a plated through hole may be formed in the support cap  206  to electrically couple the sensor  208  (i.e., resistive material) to the electrical connectors  204 , and thus, to the control system. The support cap  206  could also be configured in a skeletonized structure to further reduce thermal loss between the sensor  208  and the support cap  206 . 
     Referring to  FIG. 5 , the temperature detector probe  100 ,  200  may be provided with additional support for providing flexibility to the sensor and support cap. More particularly, a temperature detector probe  300  is configured in a similar manner as probe  200 , but includes the sensor  116  and support cap  114  of probe  100 . The probe  300  further includes a retainer ring  302  disposed at the second end portion  122  of the housing  110  and a temperature insulating material  304  (TIM) provided on the sensor  116 . The retaining ring  302  secures the support cap  114  to the housing  110 . 
     The TIM  304  is provided on the sensor  116 , such that the TIM  304  is between the sensor  116  and the surface being measured. The thickness of the TIM  304  may be based on the application using the probe  300 , and the structure of the support cap  114  and sensor  116 . For example, with the support cap  114  being 10 to 50 microns thick, the TIM  304  may be 50 to 250 microns thick. In one form, the TIM  304  is a sheet material or molded in place material that is deposited to the exposed surface of the sensor  116 . The TIM  304  is made from low hardness polymers or gels often silicone based and a combination of solid powder materials such as boron nitride, various metal oxides or metals to provide the thermal conductivity. The polymer is essentially a binder that holds this sophisticated combination of solids in usable form typically a sheet available in various thicknesses to fit the application or a dispensable liquid or paste form which may cure into a more stable soft solid material. Examples of TIM materials are Fujipoly, Sarcon, SPG20A, Sarcon GTR or Sarcon QR. The TIM  304  improves the thermal interface of the sensor  116  to the surface of the object to improve the accuracy of the temperature measurement. 
     Referring to  FIG. 6 , a temperature detector probe  400  provides another configuration for supporting and providing flexibility to the sensor. In one form, the probe  400  includes the wires (i.e., electrical connectors  204 ) and leads  202  of probe  200  to electrically couple the sensor  116  to the control system. Here, the probe  400  includes a support cap  402  provided at the second end portion  122  of the housing  110 . In one form, the support cap  402  is made of elastomer, and may be configured in various suitable ways to support the sensor  116 . For example, in one form, the support cap  402  includes a wall  404  that interfaces with an inner-wall of the housing  110 , and defines a cavity  406  for housing the sensor  116  and access ports  408  (i.e.,  408   1  and  408   2 ) for receiving the wires. 
     In one form, the temperature detector probe of the present disclosure may also include additional circuitry to process the signal from the sensor prior to providing the signal to the control system. For example, referring to  FIG. 7 , a probe  500  is configured in a similar manner as probe  200 ,  300 ,  400  and includes wires, as the electrical connectors, and leads  202 . In one form, the probe  500  includes a signal processing circuit (SPC)  502  disposed in a chamber  504  defined within the housing  110 . The SPC  702  is electrically coupled to the sensor (not shown) with a first set of wires  506  (i.e.,  506   1  and  506   2 ), and to the leads  202  via a second set of wires  508  (i.e.,  508   1  and  508   2 ). Accordingly, the wires  506  and  508  form electrical connectors that electrically couple the sensor  116  to the SPC  502 , and the SPC  502  to the leads  202 . 
     The SPC  502  may be configured in various suitable ways to condition the original signal from the sensor  116  prior to transmitting the signal to the control system. For example, in one form, the SPC  502  includes one or more electrical components to, for example, filter noise from the original signal, increase the strength of the signal, convert the signal to a particular to format utilized by the control system, convert the signal to a digital value, and/or perform a sensor offset correction. With the SPC  502 , the probe  500  can be customized for a particular control system to provide an enhanced signal based on the original signal from the sensor. In addition, SPC  502  is thermally interfaced to the housing  110 , and the housing  110  is thermally interfaced by direct contact such as an interference fit or through us of a TIM to the object  102 . The temperature of the object  102  is actively controlled and therefore, maintains SPC  502  at temperatures compatible with SPC circuitry and materials. In other words, a thermal path provided between the SPC  502  and the object  102  controls the temperature of the SPC  502  at temperatures substantially the same as that of the object  102 , which is controlled at temperatures compatible with electronic circuitry. 
     The various variations among the different probes may be interchangeable. For example, the probe  100  of  FIG. 1  may include the leads  202  and the electrical connectors  204  in lieu of the electrical connectors  112 . Conversely, the probes  200 ,  300 ,  400  and  500  may include the electrical connectors  112  of  FIG. 1  in lieu of the leads  202  and the electrical connectors  204 . 
     In yet another variation, each of the probes  100 ,  200 ,  300 ,  400  and  500  may be configured to hold an insulating gas. For example, with the grooves  120  separated from the bore  124  by a wall, the probe  400  may be filled with an insulating gas, such as Aragon, to further inhibit thermal conductivity between the housing  110  and the sensor  116 . 
     The temperature detector probes of the present disclosure are configured to inhibit thermal conductivity between the sensor from the surrounding components, such as the housing, to improve the accuracy of the measured temperature of a surface. Additional improvements to the measurement are also provided by having the sensor interface directly with the surface being measured. The addition of a TIM to the sensor surface improves thermal interfacing and sensor repeatability with the surface being measured. The flexible support cap provides a constant force against the sensor, the TIM, and the surface being sensed. 
     The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections, should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer and/or section, from another element, component, region, layer and/or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section, could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. Furthermore, an element, component, region, layer or section may be termed a “second” element, component, region, layer or section, without the need for an element, component, region, layer or section termed a “first” element, component, region, layer or section.