FR2664684A1 - Device for controlling the temperature of an article by multiple contacts - Google Patents

Abstract

- Temperature control. - The device according to the invention comprises: . a series of point contact elements (3), which can be moved axially, each in permanent contact, by one of its ends, with the article to ensure transfer of heat, on the one hand, by thermal contact between the article and the point contact elements and, on the other hand, by thermal conduction and radiation all along their surface, . means (7) for applying an axial stress onto each of the contact elements in order to hold them in permanent contact with the article, . and means (5) for support and axial guidance of each of the contact elements. - Application to cooling an article subjected to a plasma treatment.

Description

DEVICE FOR CONTROLLING THE TEMPERATURE OF A PART BY CONTACTS
MULTIPLE
The present invention relates to the technical field of temperature control and, in particular, the cooling of a part of various nature and shape, subjected to a flow of energy, such as beams of particles (photons, ions, electrons for example) or plasma.

 The invention finds particularly advantageous applications for ensuring treatment, in the general sense, such as deposition, etching or ion implantation on parts of various natures, such as those made from silicon, and intended to form, for example, microelectronics components or flat screens or those made of plastic to be coated with a protective layer or treated in order to have particular properties, in particular optical reflection.

 In the field of microelectronics, the prior art has proposed a number of solutions for cooling a part subjected to a flow of energy on one of its faces, with a view to ensuring, for example, treatment , such as ion implantation or plasma etching.

 A first known solution consists in bringing the opposite face of the face subjected to the flow of energy into contact with a cooled gas. Such a technique requires providing a seal between the two faces of the part, so as to avoid degradation of the vacuum prevailing on the side of the treatment face. In practice, it appears difficult to obtain a satisfactory seal for parts having surfaces which are not perfectly flat and / or of large dimensions and at low temperatures (up to -2000 ° C.) which are usually used for such treatments.

 To remedy this sealing problem, the prior art has proposed replacing the cooled gas with a liquid fluid at low saturation vapor pressure which improves the thermal contact between the part and the part support, so that it does not 'appears more necessary to provide sealing means. Such a technical solution has, however, disadvantages in terms of cleaning such parts, when they are in an industrial production line. Furthermore, such a technical process can no longer be implemented at low temperatures, due to the solidification of the cooling fluid.

 Another solution, known from the state of the art, consists in using an artificial fluid consisting, generally, of balls intended to be brought into contact with the face opposite that of the part receiving the energy flow. Such a solution makes it possible to remedy the problems of sealing at low temperatures.

 However, this technique has drawbacks in terms of the quality of the cooling, since the heat exchanges, by conduction or by convection, are more difficult to ensure, since the conduction takes place through the points of contact between the balls and the convection requires transport of the balls. In addition, it turns out that this technique is difficult to implement in an industrial production line, insofar as it requires, for the treatment of each part, unloading and loading of all of the balls.

 The state of the art has proposed another solution, developed in particular in the context of the treatment of polymer films and, more generally, of flexible films, such as thin metallic sheets for example. This solution consists in ensuring the movement of the thin film on a cooled cylinder in the plasma exposure zone. If this solution makes it possible to obtain suitable cooling, it should be noted that such a method is in no way suitable for the treatment of a rigid part of any shape.

 It should therefore be noted that the state of the art does not offer any industrial solution making it possible to maintain, at a given temperature, pieces of various natures and shapes subjected to a flow of energy.

 The present invention therefore aims to solve this problem by proposing a temperature control device suitable for transferring calories from a room of various shape and nature subjected to an energy flow.

 The object of the invention is also to provide a control device designed to perform its function, even in the case where the part undergoes localized deformations, due to the temperature variations which it undergoes.

The object of the invention also aims to propose a device ensuring the temperature control of a room subjected to a flow of energy directed from top to bottom or from bottom to top
The object of the invention is, again, to provide a device particularly suitable for controlling the temperature of a room subjected to an energy flow, the implementation of which is carried out under vacuum or under low pressure.

To achieve the goals set out above, the control device according to the invention, adapted to transfer the calories from a room subjected to an energy flow, is characterized in that it comprises:
- a series of punctual contact elements,
axially mobile, in permanent contact each,
by one of its ends, with the part for
to transfer calories, on the one hand,
by thermal contact between the part and the
punctual contact elements and, on the other hand,
by thermal conduction and radiation
all along their surface,
- means of applying a request
axial on each of the contact elements for
keep them in permanent contact with the part,
- and means of support and axial guidance of
each of the contact elements.

 Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the object of the invention.

 Fig.l is a schematic sectional elevation view showing an alternative embodiment of the control device according to the invention.

 Fig. 2 is a view, similar to FIG. 1, showing another alternative embodiment of the object of the invention.

 Fig. 3 is a sectional view of a particular embodiment of a part of the invention.

 Fig. 4 is a cross section showing a characteristic detail of the invention.

 Fig. 5 is a sectional elevation showing another alternative embodiment of the device according to the invention.

 Fig. 6 is a cross section of another alternative embodiment of the invention.

Fig. 1 illustrates a first alternative embodiment of a temperature control device according to
The invention makes it possible to transfer the calories from a room 1, in the general sense, subjected to an energy flow E, such as a beam of particles or a plasma, to a cold or thermostatically controlled source 2.

It should be considered that the device according to the invention allows either the transfer of calories between room 1 and a source 2 of a thermostatically controlled nature, or the removal of calories from room 1 to a cold source 2. Room 1 constitutes , in the example illustrated, a plate having a face 11 oriented downwards and receiving the energy flow. The part 1 is supported by suitable means, such as a peripheral frame, not shown but known per se.

 According to the invention, the control device comprises a series of punctual contact elements 3, such as needles, tubes or rods, designed to be in permanent contact with the part, so as to ensure a transfer of calories, on the one hand, by thermal contact between the part 1 and the contact elements and, on the other hand, by thermal conduction and radiation all along their surface.

 Each contact element 3 is axially movable, so as to remain continuously supported on the surface of the part, even if this surface does not remain flat, due, in particular, to the stresses generated by the variations in temperature. Maintaining the elements 3 in permanent contact with the surface of the part makes it possible to ensure their transfer or heat removal function. To this end, the elements 3, which are constituted or coated, at least partially, by a material having a high power of thermal conduction, such as metals, are positioned on the part, in an accessible area and subject to variations and, more particularly, at temperature rises. In the example illustrated, the elements 3 are in contact with the face 12 opposite the face receiving the energy flow and are each provided with a part terminated on 31 having a contact surface. or support, for example flat, designed to provide suitable contact between the part and the elements. The elements 3 each have a limited bearing or contact surface, due to the surface deformations likely to appear, but sufficient to ensure maximum thermal transfer by contact. By way of example, as appears more precisely in FIG. 3, each element 3 can be provided with a terminated part consisting of a deformable tip mounted by any suitable means on the element.

 Another characteristic of the contact elements 3 lies in their generally elongated shape, making it possible to ensure the thermal transfer of calories by thermal conduction and radiation all along their surface.

 Each contact element 3, which is axially movable, is supported and guided in axial displacement by means of a suitable means 5. Each support and guide means 5 can be formed, as illustrated in FIG. 1, by a tube partially surrounding an associated element 3. In addition to their support and guiding function, the tubes 5 are designed to provide a transfer or evacuation function, by conduction, of the calories exchanged with the elements 3, by means of at least two guide bearings 51 5 of the sliding element. In addition, the tubes 5 ensure the transfer, by radiation, of the calories exchanged with the elements 3, insofar as these tubes form exchange surfaces extending in proximity relationship along the major part of the elements 3. Advantageously, the tubes 5 are mounted, at their end furthest from the part, in contact with the source 2 allowing, at least by thermal conduction, to cool the tubes or a transfer of calories. The tubes are mounted by any known means on this source, such as by brazing, welding, assembly, threading or gluing.

 Each contact element 3 is associated with a means 7 adapted to apply an axial stress to it, so as to keep the elements 3 in permanent contact with the surface of the part 1. In the example illustrated in FIG. 1, the means 7 for applying an axial stress are constituted by gravity naturally acting on the elements which are limited in downward movement by a stop 8 presented by the tube and formed by a localized deformation. In the example illustrated in fig. 2, each means 7 is constituted by a spring housed inside a tube 5 and mounted to exert a force, between the bottom of the tube and the end 32 of the rod, opposite that 31 in contact with the part .It should be noted that the use of springs makes it possible to carry out a treatment of a part whose surface, subjected to the flow of energy, is directed upwards. Of course, it is possible to envisage application means 7 of different nature for exercising such a function, such as those using a magnetic or electric force for example.

The control device described above therefore ensures the transfer of the calories received by a part to a source 2. This transfer is carried out, advantageously, by permanent thermal contact between the part 1 and the elements 3, by conduction and a thermal radiation along the elements 3, the calories of which are exchanged with the tubes 5 which ensure their transfer, essentially by conduction and by radiation, to the source 2. The control device according to the invention can therefore ensure evacuation of the calories received by a room towards a cold source. The device according to
The invention also offers the possibility of maintaining the room at a constant temperature from a thermostatically controlled source.

 The control device comprises elements 3 in number adapted to ensure a total contact surface with the part, as large as possible, so as to ensure optimum removal of the calories. By way of example, provision may be made to employ approximately one hundred contact elements 3 per square centimeter. Each element 3 has, for example, an outside diameter of the order of a millimeter and a length of 100 mm.

The device according to the invention therefore allows the transfer of the calories supplied to a room, while offering the advantage of being able to be easily implemented industrially, insofar as it suffices to bring the elements 3 into contact with the part to be treated. Another advantage of the device according to
The invention relates to its ability to be able to transfer significant heat fluxes even at low temperatures. In addition, it appears possible, by this device, to control a wide range of temperatures which can even drop below 770 Kelvin.

Furthermore, it should be noted that the device according to
The invention makes it possible to obtain a uniform temperature at the level of the part, even for large parts which can reach, for example, 1 or 2 meters on a side. However, it must be considered that it is possible to use parts of size smaller than the total area constituted by the contact elements. Furthermore, such a device, which does not pose sealing problems, offers the advantage of being able to control the temperature of non-planar parts.

 An advantageous characteristic offered by such a device is the possibility of polarizing the part (continuously, low frequency or radio frequency) in the case of making the contact elements 3 and the tubes 5 according to an electrically conductive material.

 Such a device is particularly suitable for controlling the temperature of a room, during a treatment requiring reduced pressure, such as a plasma treatment. This device can also provide, for example, the plasma treatment of flat screens or microelectronics parts, the cooling of rigid non-planar plastic parts, the treatment under vacuum or under partial pressure (treatment under photon flux, etc. ..) or uniform heating of rooms.

 Fig. 3 illustrates an alternative embodiment in which each element 3 is constituted in the form of a heat tube or "heat pipe" containing a heat transfer fluid L. Such an alternative embodiment makes it possible to increase the transfer of calories between the part 1 and source 2. Of course, a similar solution could be envisaged for concentric tubes 5.

 Fig. 4 illustrates another alternative embodiment making it possible to increase the transfer of calories by radiation between the contact elements 3 and the tubes 5. According to this variant, the elements 3 and / or the tubes 5 are provided with additional exchange surfaces 10 formed, for example, by ai Lettes extending radially all along the surface of the tubes 5 and / or contact elements 3 It should be noted that the use of fins, which come into contact with the tube 5 or Element 3, increases thermal contacts. In the same direction, the radiation transfer can be increased, by increasing the absorption coefficients of the facing surfaces and / or by using absorbent coatings or frosted surfaces.

The fiv. 5 illustrates another alternative embodiment of
The invention in which exchanger elements 12 are distributed regularly between the tubes 5. The exchanger elements 12, which are in the form of needle, rod or tube, expand in relation to the tubes 5 and are mounted , preferably, directly on the source 2, cold or thermostatically controlled, as shown in 121. Preferably, the exchanger elements are each constituted in the form of a tube 122 heat or "heat pipe" containing a heat transfer fluid L .

Advantageously, the exchanger elements are formed by a tube 123 intended to be associated with a circuit 13 for circulation of a fluid directly connected to the source 2 which contains a reserve of refrigerated or thermostatically controlled fluid R. According to an advantageous characteristic, the tubes 5 can be in thermal conduction with respect to each other, or by being attached to each other, as illustrated in FIG. 5 or either by means of a filling material placed between the tubes and having a high thermal conduction power.

 It can also be envisaged to associate the exchanger elements 12 in pairs to form a return circuit for a refrigerated or thermostatically controlled fluid.

 Fig. 6 illustrates another alternative embodiment particularly suitable for small parts. To this end, the tubes 5 are placed side by side to form a bundle surrounded by a thermostated or cooled envelope 13 making it possible to control the temperature of the tubes 5 by thermal conduction, from the periphery of the bundle.

 The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope.

Claims (15)

CLAIMS:  1 - Temperature control device suitable for transferring the calories from a part (1) subjected, on at least one of its faces (11), to an energy flow (E),  characterized in that it comprises  - a series of punctual contact elements (3),  axially mobile, in permanent contact each,  by one of its ends, with the part for  to transfer calories, on the one hand,  by thermal contact between the part and the  punctual contact elements and, on the other hand,  by thermal conduction and radiation  all along their surface,  - means (7) for applying a request  axial on each of the contact elements for  keep them in permanent contact with the part,  - And means (5) for support and axial guidance  of each of the contact elements.  2 - Device according to claim 1, characterized in that the elements (3) are in permanent contact with the opposite face (1z) of that subjected to the flow of energy.  3 - Device according to claim 1, characterized in that the means (5) for support and guidance also provide a transfer function, by conduction, of the calories exchanged with the contact elements.  4 - Device according to claim 1 or 3, characterized in that the means (5) for support and guidance ensure the transfer, by radiation, of the calories exchanged with the contact elements.  5 - Device according to claim 3 or 4, characterized in that the means (5) for support and guide consist of tubes each associated with a contact element and forming a heat exchange surface extending, at least partially, in relation to a corresponding contact element.  6 - Device according to claim 1 or 5, characterized in that the tubes (5) and / or the contact elements (3) are provided with surfaces (10) for additional heat exchange.  7 - Device according to claim 5, characterized in that the tubes (5) are in thermal conduction with respect to each other  8 - Device according to claim 5 or 6, characterized in that the tubes (5) are connected to a source of polarization of the part.  9 - Device according to claim 1 or 6, characterized in that at least some of the contact elements (3) are each provided, at their end in contact with the part, with a deformable tip (31) increasing the contact surface effective thermal with the part.  10 - Device according to one of claims 1 to 9, characterized in that exchanger elements (12) are distributed regularly between the contact elements (3).  11 - Device according to claim 5 or 6, characterized in that at least some of the tubes (5) are mounted, at their end furthest from the part, in contact with a source (2) of cooling or thermostatically controlled allowing control the temperature of the tubes by thermal conduction.  12 - Device according to claims 5 and 10, characterized in that the exchanger elements (12) and at least some of the contact elements (3) and / or some of the tubes (5) are adapted to be associated with a circulation circuit of a fluid.  13 - Device according to claim 11, characterized in that each fluid circulation circuit, associated with an exchanger element (12), a tube or a contact element, is connected to a cold source (2) or thermostatically controlled.  14 - Device according to claim 11, characterized in that the fluid circulation circuits, associated with the exchanger elements, are associated in pairs to form a fluid return circuit.  15 - Device according to claim 5, characterized in that the tubes (5) are joined to form a bundle surrounded by a cooled or thermostated envelope (13) for controlling the temperature of the tubes by thermal conduction from the periphery.