US 20080225926 A1
A vacuum processing chamber for measuring the temperature of a surface of an object comprising a cap is provided. The cap has a non-deformable end wall of thermally conducting material and a side wall connected thereto. An outside surface of the end wall is shaped to conform to a shape of the object surface to be measured. A surface on an inside of the end wall of the cap emits electromagnetic radiation having a detectable optical characteristic that is proportional to the temperature of the cap end wall. The vacuum processing chamber further comprises a light wave guide having one end held within the cap a distance from the radiation emitting element and in optical communication therewith.
25. A vacuum processing chamber for performing a processing step, the vacuum processing chamber comprising:
a test substrate, said test substrate having a surface, said surface having a recess therein;
a layer of luminescent material wholly contained within the recess of the test substrate, wherein the luminescent material emits electromagnetic radiation having a detectable optical characteristic that is functionally dependent on the temperature of the test substrate in response to a source of excitation radiation;
a support disposed within the chamber, the support horizontally or vertically supporting the test substrate;
a source of excitation radiation disposed in the support, the source of excitation radiation configured to pass excitation radiation to the layer of luminescent material within the recess of the test substrate; and
a waveguide disposed in the support, the waveguide having an end, the waveguide in optical communication with the layer of luminescent material, wherein the waveguide is configured to measure temperature dependent luminescent radiation emitted by the layer of luminescent material, and wherein the end of the waveguide does not touch the layer of luminescent material.
26. The vacuum processing chamber of
27. The vacuum processing chamber of
28. The vacuum processing chamber of
physical vapor deposition;
optical coating of glass substrates;
chemical vapor deposition;
metal organic vapor deposition;
low pressure chemical vapor deposition; and
atomic layer deposition
29. The vacuum processing chamber of
30. A vacuum processing chamber for measuring the temperature of a surface of an object, comprising:
a cap having a non-deformable end wall of thermally conducting material and a side wall connected thereto, an outside surface of the end wall being shaped to conform to a shape of the object surface to be measured;
a surface on an inside of the end wall of the cap that emits electromagnetic radiation having a detectable optical characteristic that is proportional to the temperature of the cap end wall; and
a light wave guide having one end held within the cap a distance from the radiation emitting element and in optical communication therewith.
31. The vacuum processing chamber of
32. The vacuum processing chamber of
33. The vacuum processing chamber of
34. The vacuum processing chamber of
35. The vacuum processing chamber of
This application is a continuation-in-part of application Ser. No. 10/452,551, filed May 30, 2003, which is a continuation of U.S. Pat. No. 6,572,265 filed Apr. 20, 2001, the contents of each are incorporated by reference herein.
This invention relates generally to optical temperature measuring techniques, and, more specifically, to devices and techniques for contact and non-contact methods of measurement of the surface temperature of an article during processing.
There has been a great deal written about various optical temperature measuring techniques, both in patents and the technical literature, as well as many commercial products utilizing this technology. In one aspect of this technology, a luminescent material is used as a temperature sensor because certain aspects of its luminescence are temperature dependent. Typically in the form of a sensor at the end of a fiber optic cable, the luminescent material is excited to luminescence by sending excitation radiation of one wavelength to the sensor through the optical fiber, and the resulting luminescence at a different wavelength is photo-detected after passing back along the optical fiber. The detected signal is then processed to determine the temperature of the luminescent material in the sensor. Basic concepts of luminescent temperature sensing, as well as many different forms of sensors, are described in U.S. Pat. No. 4,448,547. The measurement of the decay time of the luminescence after termination of an excitation pulse, as a measurement of temperature, is described in U.S. Pat. No. 4,652,143. Commercial products adopted the decay time measurement technique as a good measurement of temperature. One advantage and focus of luminescent temperature measurement techniques has been for applications in environments having strong electric and/or magnetic fields and the like, where metal sensors cannot be relied upon to provide accurate results because the metal is heated when immersed in the electromagnetic field, causing a bias in the readings.
Applications of these luminescent sensor measurement techniques are numerous, including the measurement of surface temperature. U.S. Pat. No. 4,752,141 describes an elastomeric luminescent sensor at the end of an optical fiber that deforms as it is pushed against a surface being measured in order to establish good thermal contact. Another embodiment employing a thin non-metallic disc with a layer of luminescent material between it and the end of an optical fiber is also described.
Another optical temperature measuring technique relies upon the infrared emissions of a black-body sensor, or one having the characteristics of a black-body. An example of such a system, generally used to measure higher temperatures than measured with luminescent sensors, is described in U.S. Pat. No. 4,750,139. The sensor is a black-body emitter formed at the end of an optical fiber. U.S. Pat. No. 5,183,338 describes several forms of a fiber optic sensor that includes both luminescent and blackbody temperature measuring elements. Each of the foregoing identified patents is expressly incorporated herein in its entirety by this reference.
There are also many other optical temperature sensing techniques that have been described in patents and the literature, as well as being used commercially. But the luminescent and black-body techniques have generally been preferred over those others.
Additional aspects, features and advantages of the present invention are included in the following description of exemplary embodiments thereof, which description should be taken in conjunction with the accompanying drawings.
A sensor for measuring the temperature of the surface of an object is disclosed. The sensor has a cap having an end wall of thermally conducting material that is shaped to conform to a shape of the object. The inside surface of the end wall of the cap emits electromagnetic radiation having a detectable optical characteristic that is proportional to the temperate of the end wall. The sensor further comprises a waveguide disposed generally orthogonal to the cap. The inside surface of the cap is in optical communication with the waveguide in order to transmit the electromagnetic radiation therefrom. The sensor also has a resilient member connected to the cap in a manner to urge the cap away from the waveguide a limited distance in a manner that allows a limited degree of axial and directional freedom with respect to the waveguide. In this respect, the cap can firmly engage the object surface when positioned in contact therewith.
In accordance with another embodiment of a temperature sensor, there is provided a sensor with a thermally conducting contact having a surface that emits electromagnetic radiation with a detectable optical characteristic that is proportional to the temperature of the contact. A resilient member is attached to the contact and configured to extend the contact toward the object to be measured. A first waveguide is attached to the contact and is configured to transmit the electromagnetic radiation from the contact. The sensor further has a guide with a bore formed therein. The first waveguide is insertable into the bore such that when the contact is moved, the first waveguide moves within the bore. A second waveguide is attached to the guide such that a variable gap is formed between the ends of the first waveguide and the second waveguide. Electromagnetic energy from the first waveguide traverses the gap such that it can be transmitted by the second waveguide. In this regard, the guide allows first waveguide to be able to move with the contact in order to ensure that the contact is filly engaged with the surface of the object.
In accordance with yet another embodiment, a temperature sensor having a tip and a contact is disclosed. The temperature sensor has a thermally conducting contact with a surface that emits electromagnetic radiation with a detectable optical characteristic that is proportional to the temperature of the contact. The tip has a barrel section and a mating section and is attached to the contact. The sensor further includes a shield with an opening formed in an end thereof and an annular ledge formed around the opening. The opening is configured such that the barrel portion of the tip passes through the opening and the annular ledge is shaped to be complementary to the mating section of the tip. The sensor has a resilient member attached to the contact and is configured to extend the barrel portion through the opening such that the contact is extended toward the object. A waveguide is disposed within the tip and is configured to transmit the electromagnetic radiation emitted from the surface of the contact. The opening and the ledge allow a limited degree of rotational freedom of the tip to thereby provide engagement between the contact and the object.
The surface temperature techniques and sensors of the present invention may be used in a wide variety of environments and applications. The temperature of surfaces on any of a large number of types of objects may be measured. These measurements can be made while the object is being subjected to some processing where knowledge of the temperature of its surface is desired, or, otherwise. The example application described herein is the measurement of the temperature of the surface of substrates during one or more steps of processing to form integrated circuits and/or visual display elements such as liquid crystal display devices (LCDs) thereon. The substrate is either a semiconductor wafer or that of a flat panel display, in the examples described.
In the example of
The optical temperature measuring element of the sensor 31 may be a luminescent material that has some aspect of its luminescence highly temperature-dependent. Measurement of the decaying characteristics of the luminescent radiation output signal is usually preferred, as described in the patents discussed in the Background section above. When a luminescent sensor is employed, an excitation source 36 and beam splitter 34 are added to the configuration of
A general form of sensor 31 is illustrated in
The cap 43 may be made of a very thin heat conducting metal, such as nickel, whose substrate-contacting end does not deform in shape during normal use. In this general example, the cap 43 has a cylindrical shape in side-view, a cross-sectional side view being shown in
Four different specific embodiments of the sensor generally shown and described with respect to
In the embodiment of
A difference with the embodiment of
The embodiment of
In the embodiment of
In the sensor of
A preferred form of a cartridge sensor according to any one of
The general form of the sensors described is shown in
A different form of luminescent temperature sensor is shown in
Interrogation of the sensor 103 occurs by positioning appropriate optics to communicate with it while the substrate 101 is positioned within the processing chamber 11 (
In addition to the foregoing,
In order to communicate the optical signal from the temperature sensor 200, an optical waveguide 216 is attached to the temperature sensor 200 and an optical connecter 214 outside of the chamber 204. The optical connector 214 is attached to an optical reading device 220 such as processing element 27 as previously described. The optical waveguide 216 can be a fiber composed of sapphire or other materials that can efficiently transmit and contain optical energy. The optical waveguide 216 is protected from the environment of the chamber 204 by the shield 208 that is constructed from a thermal and optical energy reflective material such as aluminum. Because the shield 208 and the optical waveguide 216 are bent to position the sensor 200 on the underside of the substrate 202, a thermally excited output signal from the sensor 200 proceeds down the waveguide 216 and changes axial direction while remaining within the waveguide 216. The thermally excited signal then proceeds through the optical connector 214 to the reading device 220.
As previously described for the temperature sensor of
The contact 304 is fixedly attached to a resilient member 310 which is enclosed by a shield 312. The resilient member 310 may be a spring manufactured from a high thermal and reactive gas resistant material. The resilient member 310 provides a biasing force against the contact 304 such that the contact 304 is urged toward the substrate 302. Furthermore, the resilient member 310 allows the contact 304 rotational freedom to fully engage the substrate 302. The resilient member 310 maybe manufactured from quartz, glassy carbon, nanotubes or other materials. The resilient member 310 provides variable axial positioning of the contact 304 of up to 10% in the axial direction such that the contact 304 maintains physical contact with the substrate 302 when the substrate 302 is moved or repositioned. Typically, the substrate 302 is held in position above the temperature sensor 300 during processing. Therefore, the contact 304 is urged downwardly by the substrate 302 and forced upwardly by the resilient member 310. The downward force of the substrate 302 is greater than the biasing force of the resilient member 310 such that the resilient member 310 is compressed when the contact 304 physically touches the substrate 302.
As previously described, the moveable fiber 308 is fixedly attached to the contact 304. Therefore, when the contact 304 is urged downward by the substrate 302, the fiber 308 also moves downwardly. As seen in
The end of the moveable fiber 308 that is opposite the end disposed within the cavity of the contact 304 is inserted into a guide 314. The guide 314 is fixedly attached to the shield 312 and an extension 316. The guide 314 and the extension 316 are formed from high temperature and reactive gas resistive materials such as alumina. The guide 314 contains a bore 318 through which the moveable fiber 308 is inserted into. Also disposed within the bore 318 is a fixed fiber 320 that is attached to the guide 314. The fixed fiber 320 may be a silica-silica optical fiber, sapphire or other material of high optical transmissivity as is well known in the art. The moveable fiber 308 is axially moveable within the bore 318 such that a gap is formed between the ends of the moveable fiber 308 and the fixed fiber 320. The gap between the moveable fiber 308 and the fixed fiber 320 varies depending on the axial position of the contact 304. In this respect, as the contact 304 is moved downwardly, the gap between the moveable fiber 308 and the fixed fiber 320 decreases. Transmitted optical radiation can traverse the gap between the moveable fiber 308 and the fixed fiber 320. In this respect, optical radiation from the moveable fiber 308 can be transmitted through the fixed fiber 320.
The fixed fiber 320 extends from the guide 314 to a ferrule 328 in the extension 316 that is rigidly attached to a mount 326. The ferrule 328 provides a way to optomechanically couple the fixed fiber 320 to a device for measuring the signals transmitted therethrough. The ferrule 328 is attached to a base 322 made from a high temperature and reactive gas resistive material such as stainless steel. The base 328 forms a vacuum and reactive gas tight seal with the mount 326. A keeper 324 is used to urge the base 328 against the mount 326 in order to provide the vacuum and gas tight seal.
The materials of the temperature sensor 300 have thermal expansion properties to allow thermal expansion capability at relatively high temperatures. In this respect, the temperature sensor 300 can function at temperatures from −200 to 600 degrees centigrade.
The contact 402 has a cavity 404 upon which a layer 406 of phosphorescent material or black body material is deposited. The contact 402 is attached to a moveable tip 408 that is inserted within a shield 412. An adhesive layer 410 bonds the contact 402 to the tip 408.
Disposed within a cavity of the tip 408 is an optical fiber 416 that can transmit optical radiation from the layer 406. In this respect, the optical fiber 416 is positioned at a distance whereby optical radiation generated by the layer 406 can be transmitted through the fiber 416.
The tip 408 is moveable within the shield 412 and is biased toward the substrate by a resilient member 414 such as a spring. The resilient member 414 urges the tip 408 toward an annular ledge 418 formed within the end of the shield 412. A complementary mating surface 420 is formed in the tip 408. The resilient member 414 biases the mating surface 420 against the ledge 418. As can be seen in
Although the various aspects of the present invention have been described with respect to exemplary embodiments, it will be understood that the invention is to be protected within the fill scope of the attached claims. The temperature sensors previously described are ideally suited for different types of applications such as physical vapor deposition (PVD), dielectric etching, optical coating of glass substrates, chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), low pressure chemical vapor deposition (LPCVD) and atomic layer deposition.