Temperature detector probe with thermal isolation

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 longitudinally extending through the housing, and the pair of electrical connectors extend through the bore. The support cap is disposed at a first end portion of the housing. The sensor is provided on the support cap and is electrically coupled to the pair of electrical connectors. The support cap is positioned between the pair of electrical connectors and the support cap.

FIELD

The present invention relates to a surface temperature sensor device that detects a temperature of a surface.

BACKGROUND

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

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.

DETAILED DESCRIPTION

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 toFIG. 1a temperature detector probe100, which may also be referred to as a sensor device, is operable to detect the temperature of an object102, and more particularly, a surface104of the object102. The object102may be, for example, a chuck or pedestal used for processing semiconductor wafers. However, the temperature detector probe100may 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 probe100extends through the object102up to the surface104. In one form, a gap106is provided between the temperature detector probe100and the object102to reduce thermal conductivity between the object102and the probe100. The size of the gap can vary based on the application.

Referring toFIGS. 2 and 3, in one form, the probe100includes a housing110, one or more electrical connectors112(i.e.,1121and1122), a support cap114, and a sensor116. The housing110has a first end portion120and a second end portion122, and defines a bore124that extends longitudinally through the housing110between the first end portion120and the second end portion122. In one form, a cap125is provided at the first end portion120to prevent foreign matter from entering the probe100. The housing110may be viewed as having an extension portion130, which includes the first end portion120, and a sensor portion132, which includes the second end portion122. When located within the object102, the sensor portion132is positioned closer to the surface104of the object102than the extension portion130. In one form, the sensor portion132of the housing110includes one or more thermal breaks134provided as circumferential grooves defined along an exterior of the housing110to inhibit thermal conductivity between the object102and the probe100, and between the extension portion130and the sensor portion132. In one form, the thermal breaks134extend through the housing110, and in another form, a thin wall of the housing110is provided between the thermal breaks134and the bore124. The housing110may be made of plastic, such high-performance polyimide-based plastics, such as polyether ether ketone, or other suitable material.

The electrical connectors112extend through the bore124to the second end portion122of the sensor portion132. The electrical connectors112are configured to electrically couple and thus, communicably couple the sensor116to 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 probe100, and controls power to the heater system based on the signal and other inputs. This is just one example application,

The electrical connectors112extend longitudinally through the bore124and are electrically coupled to the sensor116. In one form, the electrical connectors112are a pair of pins, such as a pair of POGO pins, and each pin includes a lead portion140(i.e.,1401and1402) and a pin portion142(i.e.,1421and1422). The lead portion140extends through the first end portion120and is configured to electrically couple to a control system via a cable/wire connection. The pin portion142extends from the lead portion140to the second end portion122and is electrically coupled to the sensor116. The electrical connectors may be configured in other suitable ways, an example of which is provided below.

The support cap114is located at the second end portion122, and is configured to align and support the sensor116with the surface104of the object102. In one form, the support cap114has a disk like shape and is made of a low thermal conductive material, such as polyamide, to inhibit thermal conductivity between the sensor116and the housing110. Other materials may include elastomeric materials such as polydimethylsiloxanes. The support cap114includes a first surface that faces the bore124and a second surface that is exposed to the environment. The support cap114is configured in various suitable ways based on the size of the sensor116and packaging size of the probe100. For example, in one form, the thickness of the support cap114is approximately 0.001 to 0.005 inch. The support cap114is also configured to electrically couple the sensor116to the electrical connectors112. In one form, with the sensor116being a surface mount device, the support cap114includes plated through holes144(i.e.,1441and1442) that electrically couple to solder pads of the sensor116and to the electrical connectors112. Other suitable methods for electrically coupling the sensor116to the electrically connectors112via the support cap114may also be used while remaining within the scope of the present disclosure.

The sensor116is operable to measure a temperature of the surface104, and outputs a signal indicative of the temperature to the control system. In one form, the sensor116is a resistance temperature detector (RTD) type sensor that is located on the support cap114, and more particularly, along a second surface of the support cap114. InFIG. 3, the sensor116is 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 cap114via 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 sensor116is a thermocouple mounted to the surface of the support cap114.

Based on the application, the sensor116is configured to directly contact or be in proximity to the surface104of the object102to measure a temperature of the surface104. In one form, the support cap114has resilient or elastic qualities, such that the position of sensor116is flexible to contact the surface104of the object102. In addition, with the electrical connectors112being POGO pins, the pins provide a biasing force against the support cap114and the sensor116to have the sensor116contact the surface104.

In operation, the probe100is positioned in the object102, and is electrically coupled to the control system by way of the electrical connectors112and wires. The sensor116may be in direct contact with or is proximity to the surface104to measure the temperature of the surface104. The control system is communicably coupled to the sensor116, and receives a signal that is indicative of temperature from the sensor116.

By way of the support cap114and the housing110having the grooves, the thermal conductivity between probe100and the object and between the sensor116and the housing110is reduced or inhibited to potentially improve, for example, accuracy, response time, and offset errors of the sensor.

FIGS. 4A and 4Billustrate another variation of a temperature detector probe that has different electrical connectors and sensor. Specifically, in one form, a temperature detector probe200includes the housing110, a pair of electrical pins or leads202(i.e.,2021and2022), a pair of electrical connectors204(i.e.,2041and2042), a support cap206, and a sensor208. The electrical leads202are operable to electrically couple the probe200to the control system, and extend through the first end portion120of the housing110. The probe200further includes a cap210disposed at the first end portion120to prevent foreign material from entering the housing110.

The electrical connectors204are wires that are connected to the leads202, for example, solder or spot welding, and may be referred to as wires204. In one form, the electrical connectors204are small gauge wires, such as 36 to 40 gauge. Like the electrical connectors112of probe100, the wires204extend through the bore124and are electrically coupled to the sensor208via the support cap206.

In one form, the sensor208is a resistive element having a high TCR that is deposited on the support cap206. That is, in lieu of mounting a case having the resistive material disposed therein, the probe200provides the resistive material directly on the support cap206. 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 sensor208and reduce thermal shunting.

In one form, the support cap206is a rigid disk of low thermal expansion material such as quartz, silicon, aluminum oxide (Al2O3), aluminum nitride (AlN). In another form, the support cap206is made of a metal substrate such as stainless steel or Invar coated with a dielectric to insulate the resistive element (i.e. sensor208) from the substrate. Similar to the probe100, a plated through hole may be formed in the support cap206to electrically couple the sensor208(i.e., resistive material) to the electrical connectors204, and thus, to the control system. The support cap206could also be configured in a skeletonized structure to further reduce thermal loss between the sensor208and the support cap206.

Referring toFIG. 5, the temperature detector probe100,200may be provided with additional support for providing flexibility to the sensor and support cap. More particularly, a temperature detector probe300is configured in a similar manner as probe200, but includes the sensor116and support cap114of probe100. The probe300further includes a retainer ring302disposed at the second end portion122of the housing110and a temperature insulating material304(TIM) provided on the sensor116. The retaining ring302secures the support cap114to the housing110.

The TIM304is provided on the sensor116, such that the TIM304is between the sensor116and the surface being measured. The thickness of the TIM304may be based on the application using the probe300, and the structure of the support cap114and sensor116. For example, with the support cap114being 10 to 50 microns thick, the TIM304may be 50 to 250 microns thick. In one form, the TIM304is a sheet material or molded in place material that is deposited to the exposed surface of the sensor116. The TIM304is 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 TIM304improves the thermal interface of the sensor116to the surface of the object to improve the accuracy of the temperature measurement.

Referring toFIG. 6, a temperature detector probe400provides another configuration for supporting and providing flexibility to the sensor. In one form, the probe400includes the wires (i.e., electrical connectors204) and leads202of probe200to electrically couple the sensor116to the control system. Here, the probe400includes a support cap402provided at the second end portion122of the housing110. In one form, the support cap402is made of elastomer, and may be configured in various suitable ways to support the sensor116. For example, in one form, the support cap402includes a wall404that interfaces with an inner-wall of the housing110, and defines a cavity406for housing the sensor116and access ports408(i.e.,4081and4082) 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 toFIG. 7, a probe500is configured in a similar manner as probe200,300,400and includes wires, as the electrical connectors, and leads202. In one form, the probe500includes a signal processing circuit (SPC)502disposed in a chamber504defined within the housing110. The SPC702is electrically coupled to the sensor (not shown) with a first set of wires506(i.e.,5061and5062), and to the leads202via a second set of wires508(i.e.,5081and5082). Accordingly, the wires506and508form electrical connectors that electrically couple the sensor116to the SPC502, and the SPC502to the leads202.

The SPC502may be configured in various suitable ways to condition the original signal from the sensor116prior to transmitting the signal to the control system. For example, in one form, the SPC502includes 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 SPC502, the probe500can be customized for a particular control system to provide an enhanced signal based on the original signal from the sensor. In addition, SPC502is thermally interfaced to the housing110, and the housing110is thermally interfaced by direct contact such as an interference fit or through us of a TIM to the object102. The temperature of the object102is actively controlled and therefore, maintains SPC502at temperatures compatible with SPC circuitry and materials. In other words, a thermal path provided between the SPC502and the object102controls the temperature of the SPC502at temperatures substantially the same as that of the object102, which is controlled at temperatures compatible with electronic circuitry.

The various variations among the different probes may be interchangeable. For example, the probe100ofFIG. 1may include the leads202and the electrical connectors204in lieu of the electrical connectors112. Conversely, the probes200,300,400and500may include the electrical connectors112ofFIG. 1in lieu of the leads202and the electrical connectors204. I

In yet another variation, each of the probes100,200,300,400and500may be configured to hold an insulating gas. For example, with the grooves120separated from the bore124by a wall, the probe400may be filled with an insulating gas, such as Aragon, to further inhibit thermal conductivity between the housing110and the sensor116.

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.