Thermal exchange device with increased thermal exchange coefficient and method for production of such a device

Abstract

A heat exchange device including a first surface configured to be in contact with a source of heat to be discharged and a second surface configured to be in contact with a coolant. The device includes a plurality of recesses fluidically insulated from one another, each recess leading onto the second surface via at least one channel, each channel having a length and a transverse size that prevents the coolant from entering the recess. The second surface has better wettability properties with respect to the coolant and the inner surfaces of the channels and the recesses have wettability properties less than or equal to those of the second surface.

1 - 17 . (canceled) 
     
     
         18 . A thermal exchange device comprising:
 a first face configured to be in contact with a source of heat to be dissipated; and   a second face configured to be in contact with a cooling liquid;   wherein the device further comprises, all the way through it, between the first and second faces, multiple cavities of average radius, in which:   the cavities are isolated from one another in a fluid manner by walls, wherein each cavity emerges in the second face through at least one duct, wherein a length of each duct is greater than the average radius of the ducts, wherein the transverse dimension of the duct in an area of the connection with the cavity is such that it forms a restriction between the cavity and the duct, and wherein the second face is pierced with apertures formed by the ducts; and in which   the second face has properties of better wettability in relation to the cooling liquid, such that a contact angle of the liquid is less than 90° and a contact angle between the liquid and the inner surfaces of the ducts and cavities is greater than or equal to that between the liquid and the second face.   
     
     
         19 . A thermal exchange device according to  claim 18 , in which the ducts have a maximum diameter between 0.1D 1  and D 1 , and in which a number of ducts n is defined such that n>0.5×(D 1 /D 2 ) 2 . 
     
     
         20 . A thermal exchange device according to  claim 18 , in which
     V   total ducts >( P/P   atm )× V   cavity ,
   wherein V total ducts  is the volume formed by the sum of the volumes of each of the ducts penetrating into a cavity,   V cavity  is the volume of a cavity,   P is the absolute pressure of the cooling liquid, and   P atm  is the atmospheric pressure.   
     
     
         21 . A device according to  claim 18 , in which the walls separating the cavities have a minimum thickness of between 0.1 times and 0.2 times the average diameter of the cavities, and the apertures formed in the second face are separated by a smaller distance compared to the diameter of the apertures. 
     
     
         22 . A thermal exchange device according to  claim 18 , in which the ducts have a tapered shape, in which the smaller base is located in the area of the connection with the cavities. 
     
     
         23 . A thermal exchange device according to  claim 18 , including a matrix in which the cavities and the ducts are produced and a layer deposited on the second face, wherein the matrix has a lower wettability in relation to the liquid and the layer has a better wettability in relation to the liquid. 
     
     
         24 . A thermal exchange device according to  claim 18 , including areas with apertures formed by the ducts emerging in the second face, as structured areas, and areas without apertures, as unstructured areas. 
     
     
         25 . A thermal exchange device according to  claim 24 , in which the structured areas have a side measuring between 10 μm and 50 μm, wherein the areas are separated from one another by a distance of between 50 μm and 500 μm. 
     
     
         26 . A method for production of a thermal exchange device according to  claim 18 , in which the cavities are obtained by depositing discrete elements on a substrate, by burying the discrete elements in a layer of material forming the matrix of the thermal exchange device, to produce in the matrix of ducts until reaching the discrete elements, and to eliminate the discrete elements. 
     
     
         27 . A method for production of a thermal exchange device according to  claim 26 , including:
 a) depositing on a substrate of a barrier layer;   b) depositing a layer of discrete elements of greater average diameter, configured to demarcate the cavities;   c) depositing a layer on and between the discrete elements of greater average diameter, wherein the layer is configured to form the matrix of the device;   d) depositing discrete elements of smaller average diameter on the layer forming the matrix;   e) depositing a continuous layer on and between the discrete elements of smaller average diameter;   f) removing the discrete elements of smaller average diameter revealing apertures in the areas of which the layer forming the matrix is exposed;   g) producing ducts in the layer forming the matrix in the area of the apertures until reaching the discrete elements of greater average diameter;   h) eliminating the discrete elements of greater average diameter.   
     
     
         28 . A method for production of a thermal exchange device according to  claim 26 , in which the discrete elements are made of silica or polymer, or polystyrene, and the discrete elements are eliminated by dissolution of the discrete element by chemical attack. 
     
     
         29 . A method for production of a thermal exchange device according to  claim 27 , in which the discrete elements of smaller average diameter have an average diameter less than or equal to the average diameter of the discrete elements of larger diameter. 
     
     
         30 . A method for production of a thermal exchange device according to  claim 27 , further including reducing the size of the discrete elements of greater average diameter before the c) depositing and/or reducing, or dry etching, the size of the discrete elements of smaller average diameter before the e) depositing. 
     
     
         31 . A method for production of a thermal exchange device according to  claim 27 , in which the layer deposited in the e) depositing has better wettability in relation to the cooling liquid, or silica. 
     
     
         32 . A method for production of a thermal exchange device according to  claim 27 , in which the material forming the matrix is hydrogenated amorphous carbon. 
     
     
         33 . A method for production of a thermal exchange device according to  claim 27 , further including, before the b) depositing, depositing a preliminary layer of material forming the matrix. 
     
     
         34 . A method for production of a thermal exchange device according to  claim 27 , further including installing a mask on the stack before the f) removing the discrete elements of smaller diameter, so as to allow the discrete elements of smaller average diameter to be removed only in the area of the unmasked areas.