Abstract:
A sealed thermal interface component minimizes or eliminates the exudation of fluids, such as silicone oils, while preserving the excellent thermal conductivity of silicon-based thermal pad materials and enhancing the conformability of the component. In an example embodiment, one or more thermal pads are formed of conformable thermal management material that may exude fluid under elevated temperatures or over time. Film encapsulates the thermal pad or pads, forming a sealed and partially evacuated thermal interface component. In one embodiment of the invention, the thermal pad or pads are formed of an elastomeric silicon-based thermally conductive material and the film is made of polyurethane.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of application Ser. No. 11/704,005 filed Feb. 8, 2007, which is hereby fully incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to thermal management materials that conduct heat from a heat source to a heat-sinking component and, more particularly, components that interface between a heat source and a heat switch. 
         [0003]    During operation, IC devices produce heat. Efficient cooling systems are sometimes necessary to prevent the failure of IC devices due to this heat. Certain types of cooling systems work by transferring heat from the surface of a heat source to a heat-sinking component that dissipates the heat. Heat sinking components typically are metal, for example aluminum, and have expanded surface areas to transfer heat to the environment or may have other mechanical cooling means. When the surface of a heat source, such as an integrated circuit or a module or package containing such components, is directly engaged with the surface of a heat-sinking component, surface irregularities may prevent optimum contact and result in air spaces located in the interface between the surfaces. These air spaces can reduce the rate of heat transfer from the heat source to the heat-sinking component to unacceptable ranges. 
         [0004]    A key aspect of efficiently and effectively transferring heat from a heat source to a heat-sinking component, therefore, is maximizing heat transfer between the surfaces. To this end, an interface of thermally conductive material or a component formed from such thermally conductive material can be placed between the heat source and heat sink. Preferably, the material or compound should reduce or eliminate gaps or air spaces that resist heat transfer by maximizing contact with the surfaces of the heat source and heat-sinking components. 
         [0005]    One such material that may be used to facilitate heat transfer between a heat source and heat-sinking components is a viscous, thermally conductive paste or grease extending between the contact surfaces of the components. Such pastes or greases function by increasing surface area contact between the heat-dissipating and heat-sinking components. Furthermore, thermally conductive pastes and greases are difficult to apply and messy, and often bond to the surfaces to which they have been applied or may melt and flow under elevated temperatures. 
         [0006]    Products have been developed to avoid some of the problems associated with thermally conductive pastes and greases and still facilitate heat transfer through an interface. For example, thermal pads are now made from an elastomeric or foam matrix material loaded with a material that has favorable thermally conductive characteristics. Thermal pads, including those loaded with such materials, are further described in U.S. Pat. Nos. 6,054,198; 5,679,457; 5,545,473; 5,510,174; 5,309,320; 5,298,791; 5,213,868; 5,194,480; 5,137,959; 5,151,777; 5,060,114; 4,979,074; 4,869,954; 4,782,893; 4,685,987; 4,606,962; and 4,602,678. These patents are incorporated herein by reference. 
         [0007]    By combining the elastomeric-conforming properties of one material with the favorable thermally conductive properties of another, thermal pads loaded with a thermally conductive material can significantly reduce air spaces and facilitate heat transfer between the surfaces of a heat source and heat-sinking components. Silicone-based materials have come into favor in thermal management materials due to their excellent heat transfer capabilities and their high conformability under compression. Such compression can cause many of these silicone-based materials to effectively flow rather than to simply be compressed, essentially maintaining the original volume of the pad. Especially when used under conditions of continuous elevated temperatures, these silicone-loaded pads have a tendency to exude fluids, for example, silicone and other fluids and may out-gas. These fluids and gases, in turn, may contaminate the IC devices or other components or portions of the equipment. In some applications, this is not a concern, but in many applications, such exudation and/or outgassing is not acceptable. 
         [0008]    It is considered by many in the field that thermal pad materials based on or loaded with a non-silicone material are not as effective as other materials in transferring heat and in conformability. 
         [0009]    Thus, there is a need for an effective thermal interface component that has the performance characteristics of silicone-based or silicone-loaded thermal pad material but that does not exude silicone or oils under operating conditions. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention meets the aforementioned needs of the industry, in particular by providing a sealed thermal interface component that minimizes or eliminates the exudation of fluids, such as silicone oils, while preserving the excellent thermal conductivity of silicon-based thermal pad materials and enhancing the conformability of the component. In preferred embodiments, a foam frame surrounds a plurality of thermal pad portions formed of conformable thermal management material that may exude fluid under elevated temperatures or over time. In other embodiments, the sealed thermal interface component does not utilize a foam frame. Film encapsulates the foam-framed thermal pad portions, forming a sealed and partially evacuated thermal interface component. Alternatively, film may encapsulate one or more thermal pad portions that are not framed within foam. In a preferred embodiment of the invention, the thermal pads are formed of an elastomeric matrix material containing silicone, the foam frame is made of polyurethane, and the film is made of urethane. One skilled in the art will recognize that the foam frame is an optional feature of the thermal interface component. Utilization of the foam frame may depend, for example, upon the application of the thermal interface component and the preferences of manufacturers and end users of the thermal interface component. 
         [0011]    In preferred embodiments, in the encapsulation process, air is evacuated from the interior of the encapsulation, thus eliminating of minimizing air gaps or pockets from within the sealed thermal interface component. The encapsulating film is heat sealed around the foam-framed thermal pad portions. The minimal amount of air present in the evacuated component is conducive to excellent thermal transfer characteristics. 
         [0012]    Compression of thermal interface management materials between heat source and heat-sinking components generally causes some flowing of the conformable material. This increase in pressure causes the thermal pads to expand along axes perpendicular to the axis of compression. Such compression and the resultant flowage can rupture a simple encapsulation of the material due to the buildup of internal pressure caused by the flowage. The foam frame prevents rupture of the encapsulating film by compressing and allowing lateral expansion by the thermal pads within the component. In embodiments not having the foam frame, selecting a thickness and geometry for the thermal pad that permits compression while limiting lateral expansion within a resilient film can prevent rupture of the encapsulating film. The presence of a bolt hole designed to facilitate attachment of the sealed thermal interface component can also provide additional room for lateral expansion of the thermal pad. The present invention thereby provides a thermal interface material flow management system. 
         [0013]    Another feature and advantage of the preferred embodiments of the invention is the use of a heat-sealed encapsulating film. When heat-sealed, the encapsulating film prevents the exudation of silicone oils, maintains a vacuum within the sealed thermal interface component, enhancing thermal conductivity, and accommodates volumetric displacement of the foam-framed or non-framed thermal pad without rupture or leakage during compression. 
         [0014]    A further feature and advantage of preferred embodiments of this invention is presented relating to the optional use of foam as a framing component within the sealed thermal interface component. Components formed from a simple encapsulation of conformable heat transfer materials may not adequately contain fluids that may exude from the material, particularly when the component is severely compressed. The foam frame is available for absorbing the silicone oil exuded from the thermal management material in the component. In other applications, the film-encapsulated thermal pad may adequately contain fluids that may exude from the material, even when compressed, and the thermal interface component need not include the foam frame. The present invention thereby provides a thermal interface material fluid exudation management system through absorption and containment. 
         [0015]    Another feature and advantage of the preferred embodiments of this invention is the creation of a vacuum within the encapsulating film while simultaneously heat sealing the encapsulating film. This removes and maintains the absence of air spaces from the sealed thermal interface. Air may inhibit heat transfer and the vacuum-induced lack of air within the thermal interface component increases the thermal transfer performance. 
         [0016]    Another feature and advantage of the preferred embodiments of the invention is the presence of a control means for silicone oil in the thermal interface. Said means comprises a containment for the oil as well as an liquid-absorbing capability within the thermal interface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of a thermal interface component according to the invention. 
           [0018]      FIG. 2  is a cross-sectional view of the sealed thermal interface component of  FIG. 1  taken at line  2 - 2 . 
           [0019]      FIG. 3  is a cross-sectional view of the sealed thermal interface component of  FIGS. 1 and 2 . 
           [0020]      FIG. 4  is an enhanced cross-sectional view of the sealed thermal interface component shown in  FIG. 1  compressed between a heat source and a heat-sinking component. 
           [0021]      FIG. 5  a perspective view of a thermal interface component according to the invention. 
           [0022]      FIG. 6  is a cross-sectional view of the sealed thermal interface component of  FIG. 5  taken at line  6 - 6 . 
           [0023]      FIG. 7  is a cross-sectional view of the sealed thermal interface component shown in  FIG. 6  compressed between a heat source and a heat-sinking component. 
           [0024]      FIG. 8  is a perspective view of the apparatus and process used to encapsulate the thermal interface pad between two layers of film and remove air spaces from the encapsulation. 
           [0025]      FIG. 9  is a perspective view of the apparatus and process used to heat-seal the framed thermal interface pads between two layers of film. 
           [0026]      FIG. 10  is a perspective view of framed thermal interface pads components sealed between two layers of film. 
           [0027]      FIG. 11  is a cross-sectional view of the overlapping juncture of the heat-sealed upper and lower layers of film around the outer edge of the foam frame after having been trimmed. 
           [0028]      FIG. 12  is a cross-sectional view of the thermal interface component of  FIG. 11  after the loose edges are heat sealed to the side of the component overlapping juncture of the heat-sealed upper and lower layers of film after they have been folded so as to conform to the edge of the foam frame. 
           [0029]      FIG. 13  is a perspective view of a thermal interface component according to an embodiment of the present invention. 
           [0030]      FIG. 14  is cross-sectional view of the sealed thermal interface component shown in  FIG. 13 . 
           [0031]      FIG. 15  is a perspective view of a thermal interface component according to an embodiment of the present invention adapted to receive a fastening member through the shown bolt hole. 
           [0032]      FIG. 16  is a cross-sectional view of the sealed thermal interface component shown in  FIG. 15  having upper and lower films heat sealed in the bolt hole. 
           [0033]      FIG. 17  is a cross-sectional view of the sealed thermal interface component shown in  FIG. 16  with a fastening member inserted therethrough. 
           [0034]      FIG. 18  is a cross-sectional view of the sealed thermal interface component shown in  FIG. 17  compressed between a heat source and a heat-sinking component and the fastening member secured to the heat-sinking component. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0035]    The present invention includes a heat-sealed thermal interface component for facilitating heat transfer between a heat source and a heat-sinking component. Referring to  FIGS. 1 ,  2 ,  5 ,  6 , and  13 - 16 , different embodiments of the sealed thermal interface component  18 ,  19 ,  20 ,  21  are illustrated. The components generally have a top side  21 . 1  with a top surface  21 . 2 , a bottom side  21 . 3  with a bottom surface  21 . 4 , and a side  21 . 5  with a side surface  21 . 6 . In preferred embodiments the component is a sheet configuration with a maximum thickness of about 0.03 inches to about 0.50 inches (in the z direction of the x-y-z coordinate system) and surface area (in the x and y plane) of about 2 square inches to about 36 square inches. More preferably, the component has a thickness of 0.06 to 0.16 inches. The component may have a thickness that varies slightly due to different thicknesses of the base components and compression that occurs during manufacture, specifically the partial evacuation. When used herein, the terms “partial evacuation” and “vacuum” indicate that the component was sealed with the interior of the encapsulation at a negative pressure that is below the atmospheric pressure at the time and point of encapsulation. When used herein, the term “evacuation form fit” indicates a partial evacuation substantially conforming to the space occupied by object, such as, for example, the partial evacuation between an encapsulating film and a thermal pad. Such form fit may include some spatial compression of the object or portions of the object being compressed. 
         [0036]    Referring to  FIGS. 2-4 ,  6 - 7 , and  11 - 12 , detailed cross-sectional views of sealed thermal interface components  20 ,  21  are illustrated. Sealed thermal interface components  20 ,  21  are principally made up of foam frame  24 , thermal pads  22 , upper film  26 , and lower film  28 . In an example embodiment, sealed thermal interface components  20 ,  21  comprise thermal pads  22  situated inside frames  24 , preferably foam frames. Foam frames  24  and thermal pads  22  are sealed between an upper film  26  and a lower film  28 . The films  26 ,  28  are preferably transparent and encapsulated  29  or form an uninterrupted barrier around foam frame  24  and thermal pads  22 . 
         [0037]    Referring to FIGS.  14  and  16 - 18 , cross-sectional views of sealed thermal interface components  18 ,  19  are also illustrated. Sealed thermal interface components  18 ,  19  are principally made up of thermal pads  22 , upper film  26 , and lower film  28 . Unlike sealed thermal interface components  20 ,  21  illustrated in  FIGS. 2-4 ,  6 - 7 , and  11 - 12 , sealed thermal interface components  18 ,  19  illustrated in  FIGS. 13-18  do not have foam frame  24 . Although  FIGS. 13-18  illustrate thermal interface components that have only one thermal pad  22 , one skilled in the art would recognize that thermal interface components  18 ,  19  without foam frame  24  could have multiple thermal pads  22  without departing from the spirit or scope of the present invention. In an example embodiment, sealed thermal interface components  18 ,  19  each comprise a single thermal pad  22 . Thermal pad  22  is sealed between an upper film  26  and a lower film  28 . The films  26 ,  28  are preferably transparent and encapsulated  29  or form an uninterrupted barrier around foam frame  24  and thermal pads  22 . 
         [0038]    Thermal pad  22  is made from a compressible and conformable thermal management material suitable for transferring heat from an integrated circuit (IC) device to a cooling block. In one embodiment, the thermal management material is an elastomeric matrix loaded with silicone, metal composites, or other thermally conductive material. The thermal conductivity of thermal pad  22  is typically in a range of about 0.04 watts per meter per degree Kelvin (“w/m-K”) to 20.0 w/m-K, or more preferably a range of about 0.4 w/m-K to about 5.0 w/m-K, or about 0.74 w/m-K to about 2.3 w/m-K. The thermal resistance of thermal pad  22  is preferably in a range of about 50 degrees Celsius by square millimeters per watt (“C-mm 2 /w”) to about 200 C-mm 2 /w, or more preferably about 80 C-mm 2 /w to about 190 C-mm 2 /w. The dielectric breakdown strength of thermal pad  22  is preferably in a range of about 100 volts per millimeter (V/m) to about 1000 V/m, or more preferably a range of about 523 V/m to about 882 V/m. The Shore A hardness is preferably in a range of about 10 to about 200, or more preferably about 70 to about 100. A preferred material for the thermal pads is Thermagon T-flex 6100, manufactured by Laird (Cleveland, Ohio). Other materials with similar characteristics may also be used. Also Gap Pad® and Gap Filler® materials available from The Bergquist Company of Chanhassen, Minn. are believed to be suitable. These materials are typically silicon based 
         [0039]    As shown in  FIGS. 4 ,  7 , and  18 , sealed thermal interface components  18 ,  19 ,  20 ,  21  may be compressed between heat source  52  and heat-sinking component  54 . Compression of thermal pad  22  between heat source  52  and heat-sinking component  54  alters the shape and may change the volume of the components  18 ,  19 ,  20 ,  21  and of the thermal pads  22 , causing flowage of thermal pad  22  material. 
         [0040]    The thickness of foam frame  24  is preferably less than the thickness of thermal pads  22 . This optimizes the ability of foam frame  24  to accommodate expansion of thermal pads  22  without rupturing films  26 ,  28  during compression. In certain applications, however, foam frame  24  may not be necessary to accommodate expansion of thermal pads  22  without rupturing films  26 ,  28  during compression. The thickness of thermal pads  22  is preferably in a range of about 0.03 inches (in.) to about 0.50 in., or more preferably about 0.06 in. to about 0.16 in. In more preferred embodiments, the thickness of thermal pads  22  is about 0.10 in. thick and the thickness of foam frame  24  is about 0.045 in. thick. 
         [0041]    Thermal pads  22  may be of any suitable shape and the corresponding cooperating frame  24  any suitable complementary shape. In one embodiment, thermal pads  22  are substantially square in shape, as shown in  FIGS. 1 and 13 . In another embodiment, thermal pads  22  may be shaped to substantially match the shape of a particular heat source  52 . In another embodiment, thermal pads  22  contain an aperture or are slotted to provide volume-absorbing gaps  57  laterally (in the x-y plane) between for expansion due to compression of thermal pads  22 , as shown in  FIGS. 5 and 6 . In another embodiment, thermal pad  22  contains bolt hole  59 . 1  or other aperture through which fastening member  59 . 2  may be inserted. Fastening member  59 . 2  may be used for a variety of purposes, but principally facilitates attachment of sealed thermal interface component  19  to heat-sinking component  54  or heat source  52 .  FIGS. 15-18  depict bolt holes  59 . 5  in embodiments of the present invention not having  19  not having foam frame  24 . Though not shown, embodiments of the present invention having foam frame  24  could easily be adapted to comprise bolt hole  59 . 2 . 
         [0042]    Thermal pads  22  may be spaced in any suitable configuration. In one embodiment, thermal pads  22  are spaced substantially evenly in foam frame  24 , as shown in  FIG. 1 . In another embodiment, thermal pads  22  may be spaced and configured to align with specific heat sources  52 , as shown in  FIG. 5 . In another embodiment, thermal pads  22  are not placed in foam frame  24 , as shown in  FIGS. 13 and 15 . 
         [0043]    During compression, normally in the z direction, thermal pad  22  expands outward along axes perpendicular to the axis of compression, that is the x and y directions, as shown in  FIGS. 4 and 7 . As shown in  FIG. 4 , foam frame  24  may contract near edge  36  of the component to accommodate glacial expansion of thermal pads  22 . In one embodiment, lateral expansion of thermal pads  22  is accommodated by placing thermal pads  22  in foam frame  24  shaped like a window grille, as shown in  FIGS. 1 and 2 . In another embodiment, lateral expansion of thermal pads  22  is accommodated by removing material from thermal pads  22  to create volume-absorbing gaps  57  prior to encapsulation. As shown in  FIG. 7 , thermal pads  22  expand into volume-absorbing gaps  57  during compression and may cause expansion of the region  57 . 1  between the upper and lower films. There may also be the closed but unsealed two layers of film at the edges of the component that allows the thermal pad to push beyond the previous perimeter or edge of the component. For example in  FIG. 11 , the end  58 . 1  of the overlapping layers of film may be sealed but the adjacent portion  58 . 2  not sealed to allow the thermal pad to expand therein. 
         [0044]    The glacial expansion of thermal pads  22  that occurs under compression can also be contained without the use of foam frame  24 . Specifically, forming thermal pads  22  of a particular geometry and selecting thermal management material of a particular thickness can substantially limit displacement of the thermally conductive material from which thermal pads  22  are made. Selecting a resiliently expandable film for encapsulation of thermal pads  22  can further assist in limiting displacement of the thermally conductive material so that thermal interface component  18 ,  19  does not rupture under compression. A variety of dimensions and thicknesses of thermal pads  22  may permit embodiments of the present invention without foam frame  24  to be compressed without rupturing. In embodiments of the present invention without foam frame  24 , thermal pad  22  generally has a thickness in the range of about 0.010 inches to about 0.100 inches. Thermal pad  22  may also have a thickness in the range of about 0.30 inches to about 0.070 inches. In an example embodiment, thermal pad  22  has a thickness of about 0.040 inches.  FIGS. 13 and 15  depict thermal interface components having a generally square shape. Thermal interface components  18 ,  19  may, however, comprise any number of shapes that facilitate compression of thermal pads  22  without rupturing the encapsulation. Although foam frame  24  may still be used in these embodiments, their use may not be necessary. 
         [0045]    During compression of sealed thermal interface  20 , thermal pads  22  may exude fluid that was loaded into or that is part of thermal pads  22  to facilitate heat transfer. Thermal pads  22  comprising a filled silicone elastomer, for example, may exude silicone fluids. Surrounding thermal pads  22  and foam frame  24  with upper film  26  and lower film  28  sealed at overlapping juncture  34  may absorb and contain silicone fluids and other potential contaminants within sealed thermal interface components  20 ,  21 . Referring to  FIGS. 13-14 , the present invention also includes non-framed embodiments of thermal interface components  18 ,  19  having a single thermal pad  22  or multiple thermal pads  22  surrounded by upper film  26  and lower film  28  sealed at overlapping juncture. Such embodiments similarly contain silicone fluids and other potential contaminants within thermal interface components  18 ,  19 . 
         [0046]    The encapsulation formed by upper film  26  and lower film  28  completely surrounds and seals therein thermal pads  22  and, in certain embodiments, foam frame  24  as well. In preferred embodiments, interfaces  32  between films  26 ,  28  and foam frame  24  and interfaces  32  between films  26 ,  28  and thermal pad  22  are substantially free of air spaces. Films  26 ,  28  are substantially coextensive with the surface of thermal pads  22  and foam frame  24 . In embodiments of the present invention having bolt hole  59 . 1 , upper film  26  and lower film  28  may or may not dip into the cavity defined by bolt hole  59 . 1 . In an example embodiment, upper film  26  and lower film  28  overlap in at least a portion of bolt hole  59 . 1 , as depicted in  FIG. 16 . 
         [0047]    Upper film  26  and lower film  28  are integrally joined or otherwise hermetically sealed at overlapping juncture  34 . In one embodiment, overlapping junction  34  follows the circumference of foam frame  24  substantially coextensive with outer edge  36  of foam frame  24 . In another embodiment, overlapping juncture  34  follows the circumference of thermal pad  22  substantially coextensive with outer edge  37  of thermal pad  22 , as depicted in  FIG. 14 . Overlapping junction  34  may be folded upon itself to lie coextensive with upper film  26  or lower film  28 , as shown in  FIG. 12  thereby providing further reinforcement to the juncture  34 . 
         [0048]    Referring to  FIG. 16 , upper film  26  and lower film  28  may also be integrally joined or otherwise hermetically sealed at overlapping bolt hole juncture  59 . 3 . In one embodiment, overlapping bolt hole juncture  59 . 3  is substantially coextensive with the inner surface of thermal pad  22  defined by circumference bolt hole  59 . 2 . In another embodiment, a gap exists between holt hole juncture  59 . 3  and an interior edge of thermal pad  22  defined by circumference of bolt hole  59 . 2 . 
         [0049]    Generally, the heat-sealed or otherwise hermetically sealed portion of overlapping bolt hole juncture  59 . 3  comprises an area capable of receiving the shaft of a fastening member without compromising the integrity of the film seal around thermal pad  22 . In an example embodiment, a portion of overlapping bolt hole juncture  59 . 3  coextensively surrounds the perimeter of the shaft of fastening member  59 . 2 , such as is depicted in  FIG. 17 . To facilitate insertion of fastening member  59 . 2  through bolt hole  59 . 1  without destroying the vacuum within the encapsulation, overlapping bolt hole juncture  59 . 3  may be pre-cut or scored. To accommodate fastening member  59 . 2 , bolt hole  59 . 1  may comprise any number of shapes and sizes. Generally, bolt hole  59 . 1  is cylindrical and has a radius in the range of about 0.05 inches to about 0.50 inches. Bolt hole  59 . 1  may also have a radius in the range of about 0.10 inches to about 0.20 inches. In an example embodiment, bolt hole is large enough to accommodate a No. 6 screw (which has a diameter of approximately 0.1380 inches) without compromising the integrity of the film encapsulation. 
         [0050]    Films  26 ,  28  are suitably polyurethane. Films  26 ,  28  may be deformed, and are suitably elastic. When sealed thermal interface component  20  is compressed, such as, for example, between an integrated circuit (IC) device and a cooling block, films  26 ,  28  accommodate volumetric expansion of thermal pads  22  without rupturing. As shown in  FIGS. 3 ,  4 ,  6 , and  7 , the thickness of upper film  26  is substantially the same as the thickness of lower film  28 . The thickness of films  26 ,  28  is preferably in a range of about 0.5 thousandths of an inch (mil) to about 3.0 mils, or more preferably about 1.0 mils to about 2.0 mils. In a most preferred embodiment, the thickness of films  26 ,  28  is about 1.4 mils. A preferred film is Duraflex X1843, manufactured by Deerfield Urethane (South Deerfield, Mass.). Use of such films and such relatively thin films provide minimal additional heat transfer resistance to the component. 
         [0051]    In operation, sealed thermal interface component  20  facilitates heat transfer. As shown in  FIGS. 4 ,  7 , and  18 , sealed thermal interface component  19 ,  20  is compressed between heat source  52  and heat-sinking component  54  to achieve coextensive thermal communication between sealed thermal interface component  20  and adjacent surfaces of heat source  52  and heat-sinking component  54 . Heat source  52  generates heat, which is transferred through sealed thermal interface component  20  to heat-sinking component  54 . In preferred embodiments, heat source  52  may be an integrated IC device and heat-sinking component  54  may be a cooling block. Referring to  FIG. 2 , a pressure sensitive pad  54 . 2  may be applied to the component to facilitate attachment to the heat generating component or heat sink. 
         [0052]    In manufacturing sealed thermal interface component  20 , thermal pads  22  are cut from a sheet of thermal management material. In one embodiment of this method, thermal pads  22  are cut using a water-jet apparatus. Use of a water jet apparatus minimizes deformation of thermal management material during the cutting process. In another embodiment of this method, thermal pads  22  are cut using a die-cutting apparatus. Typically, there are layers of backing on the thermal management material that is preferably removed before encapsulating. 
         [0053]    In manufacturing sealed thermal interface component  20 , foam frame  24  may be cut from a sheet of foam material. This process includes cutting the outer shape and dimensions of foam frame  24  as well as apertures in foam frame  24  that will accept thermal pads  22 . In preferred embodiments of this method, foam frame  24  is cut using a water-jet apparatus. In another embodiment of this method, foam frame  24  is cut using a die-cutting apparatus. A preferred foam is Poron 4701-30, manufactured by Rogers Corporation (Woodstock, Conn.). The foam frames have a inner geometry, such as the windows  25 . 5 , and an outer geometry  25 . 6 . The thermal pads are sized for insertion in the inner geometry. 
         [0054]    In manufacturing sealed thermal interface components  20 ,  21  having foam-framed thermal pads  22 , thermal pads  22  are placed in apertures in foam frame  24 . In preferred embodiments of this method, thermal pads  22  are placed by hand in apertures cut in foam frame  24 . Inserting thermal pads  22  by hand into apertures in foam frame  24  minimizes deformation of thermal management material  36 . In another embodiment of this method, thermal pads  22  are placed into apertures in foam frame  24  by a machine. 
         [0055]    In manufacturing sealed thermal interface component  20 , upper film  26  and lower film  28  are cut from roll of film. In preferred embodiments, lower film portions  28  are cut so as to be narrower and shorter than upper film  26 , as shown in  FIGS. 8-10 . 
         [0056]    In manufacturing sealed thermal interface component  20 , lower film  28  is placed onto vacuum table  40  connected to vacuum hose  42 , as shown in  FIG. 8 . Thermal pads  22 , including thermal pads  22  contained in foam frame  24 , are placed onto lower film  28 , as shown in  FIG. 8 . In preferred embodiments, foam frame  24  already containing thermal pads  22  is placed onto lower portions film  28 . In another embodiment, thermal pads  22  are placed onto foam frame  24  and onto lower film  28  after foam frame  24  is placed onto lower film  28 . In another embodiment, foam frame is placed around thermal pads  22  and onto lower film  28  after thermal pads  22  are placed onto lower film  28 . In preferred embodiments, a plurality of foam frames  24  containing thermal pads  22  are placed over lower film  28 . In another embodiment, single foam frame  24  containing thermal pads  22  is placed over foam frame  24  containing thermal pads  22 . In another embodiment, a single thermal pad  22  is placed onto lower film  28 . In yet another embodiment, a plurality of thermal pads  22  are placed onto lower film  28 . 
         [0057]    In manufacturing sealed thermal interface component  20 , upper film  26  is adhered to rigid frame  58 . Rigid frame  58  is lowered and upper film  26  is thereby placed over foam frame  24  containing thermal pads  22  and over lower film  28 . In preferred embodiments, upper film  26  is placed over a plurality of foam frames  24  containing thermal pads  22 . In other embodiments, upper film  26  is placed over a plurality of thermal pads  22 . 
         [0058]    In manufacturing sealed thermal interface component  20 , the internal pressure of vacuum table  40  becomes lower than the ambient pressure when the vacuum is engaged. This pressure differential creates a negative force through an array of inner holes  38  and outer holes  60  in the top surface of vacuum table  40 . As shown in  FIG. 8 , when lower film  28  is placed on vacuum table  40 , the outer edge of lower film  28  is located between inner holes  38  and outer holes  60  at the position  58  defined by the dashed lines. The negative force through the array of inner holes  38  holds lower film  26  in place on vacuum table  40 . At this point, air continues to pass through outer holes  60 , but no longer passes through inner holes  28 . When upper film  26  is placed over thermal pads  22 , including thermal pads  22  contained in foam frame  24 , the outer edge of upper film  26  lies outside the array of outer holes  60 . As this point, all holes  38 ,  60  are substantially covered and air no longer passes through holes  38 ,  60 . The negative force through the array of outer holes  60  holds upper film  60  in place over foam frame  24  containing thermal pads  22  and over lower film  28 . Since upper film  26  is wider and longer than lower film  28 , vacuum table  40  holds upper film  26  in place over lower film  28  coextensively along overlapping juncture  34 . In preferred embodiments, upper film  26  is placed over a plurality of foam frames  24  containing thermal pads  22 . In another embodiment, upper film  26  is placed over a single foam frame  24  containing thermal pads  22 . In another embodiment, upper film  26  is places over a single thermal pad  22 . In yet another embodiment, upper film  26  is placed over a plurality of thermal pads  22 . 
         [0059]    In manufacturing sealed thermal interface component  20 , air spaces are removed from overlapping juncture  34  between upper film  26  and lower film  28  so that films  26 ,  28  are substantially coextensive with thermal pads  22  and foam frame  24 . Air spaces are also substantially removed from between upper film  26  and lower film  28  at overlapping juncture  34 . When necessary due to the geometry of thermal pads  22 , air is also removed from gaps  57 . In preferred embodiments, air spaces are removed by exerting downward pressure on the upper film  26  and foam frame  24  containing thermal pads  22 . 
         [0060]    In manufacturing sealed thermal interface component  20 , overlapping juncture  34  is sealed. In embodiments of the present invention having bolt hole  59 . 1 , overlapping bolt hole juncture  59 . 3  may also be sealed at this stage. In preferred embodiments of this method, overlapping juncture  34  and overlapping bolt hole juncture  59 . 3  are heat sealed. As shown in  FIG. 9 , heated sealing walls  46  are adapted to form cavities  62  that fit over and around foam frames  24  containing thermal pads  22 . Heated sealing walls  46  can also be adapted to form cavities  62  that fit over thermal pads  22  not having foam frame  24  and to fit into overlapping bolt hole juncture  59 . 3 . The height of cavities  62  is slightly larger than the height of thermal pads  22 . The shape of cavities  62  is substantially the same and slightly larger than the outer shape of foam frames  24  such that sealing walls  46  conform to foam frames  24  containing thermal pads  22 . The shape of cavities  62  may also be substantially the same and slightly larger than the outer shape of thermal pads  22  such that sealing walls  46  conform to thermal pads  22  or a plurality of thermal pads  22 . In preferred embodiments, heated sealing walls  46  are affixed onto a movable heating press. The movable heating press is lowered such that each cavity  62  surrounds foam frame  24  containing thermal pads  22  or thermal pads  22  without foam frame  24 . Films  26 ,  28  are pinched between contact surfaces of heated sealing walls  46  and vacuum table  40 . Movable heating press is raised after overlapping juncture  34  has been sufficiently sealed. In other embodiments, overlapping juncture  34  is sealed by alternative means, such as, for example, by application of an adhesive. In preferred embodiments, a package  64  of several foam frames  24  containing thermal pads  22  are independently sealed between upper film  26  and lower film  28 . In another, embodiment, a single foam frame  24  containing thermal pads  22  is sealed between upper film  26  and lower film  28 . In another embodiment, a package  64  of several thermal pads  22  are independently sealed between upper film  26  and lower film  28 . In yet another embodiment, a single thermal pad  22  is sealed between upper film  26  and lower film  28 . 
         [0061]    In manufacturing sealed thermal interface component  20 , excess upper film  26  and excess lower film  28  are removed. As shown in  FIG. 11 , a discrete portion of heat-sealed films  26 ,  28  remains around outer edge  36  of foam frame  24 . In preferred embodiments of this method, excess upper film  26  and excess lower film  28  are removed by a die-cutting apparatus. As shown in  FIG. 12 , the portion of heat-sealed films  26 ,  28  forming overlapping junction  34  that remains after excess upper film  26  and excess lower film  28  are removed is folded over sealed thermal interface  20  and sealed with heat and pressure. Overlapping junctions  34  may be folded or left unfolded both in embodiments of the present invention having foam frame  24  as well as embodiments of the present invention without foam frame  24 . 
         [0062]    The embodiments above are intended to be illustrative and not limiting. Additional embodiments are within the claims. Although the present invention has been described with reference to particular embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. 
         [0063]    Some embodiments of the invention may include a simple encapsulation of the thermal pads without the foam framing or utilizing another framing material such as rigid of soft polymers.