Process for assembling substrates with low-temperature heat treatments

Abstract

The invention relates to a process for producing a bond between a first and a second substrate ( 2, 4 ), comprising: a) a step of preparing surfaces ( 6, 8 ) to be assembled, b) an assembly of these two surfaces, by direct molecular bonding, c) a heat treatment step involving at least maintaining the temperature within the range of 50° C. to 100° C. for at least one hour.

1 - 30 . (canceled) 
   
   
       31 . Process for producing a bond between a first and a second substrate, comprising:
 a) a step of preparing surfaces to be assembled,   b) an assembly of these two surfaces, by direct molecular bonding,   c) a heat treatment step involving at least maintaining the temperature within the range of 50° C. to 100° C. for at least one hour, then maintaining the temperature in the range strictly above 100° C. and below or equal to 500° C. for at least one hour.   
   
   
       32 . Process according to  claim 31 , said step c) comprising a passage through successive and/or cumulative temperature levels. 
   
   
       33 . Process according to  claim 32 , said temperature levels being successive, without a return to room temperature. 
   
   
       34 . Process according to  claim 32 , said temperature levels being cumulative, with, between two successive temperature levels, a return to a temperature below the temperatures of two levels. 
   
   
       35 . Process according to  claim 34 , the lower temperatures between two successive levels being all identical. 
   
   
       36 . Process according to  claim 35 , the lower temperatures between two successive levels being all equal to room temperature. 
   
   
       37 . Process according to  claim 32 , the temperature levels being produced at temperatures increasing over time. 
   
   
       38 . Process according to  claim 32 , at least one of the temperature levels comprising a rate of temperature increase below 5° C. per minute. 
   
   
       39 . Process according to  claim 31 , said step of preparing the surfaces being a hydrophilic or hydrophobic treatment step. 
   
   
       40 . Process according to  claim 31 , said assembly being produced by bonding, under a controlled atmosphere. 
   
   
       41 . Process according to  claim 31 , at least one of the two substrates being a semiconductor material. 
   
   
       42 . Process according to  claim 31 , at least one of the two substrates being made of silicon. 
   
   
       43 . Process according to  claim 31 , the two substrates being made of silicon. 
   
   
       44 . Process according to  claim 31 , the two substrates at least having a silicon dioxide surface. 
   
   
       45 . Process according to  claim 31 , one of the two substrates having at least a surface of silicon dioxide and the other is silicon. 
   
   
       46 . Process according to  claim 31 , the two substrates being made of materials with different heat expansion coefficients. 
   
   
       47 . Process according to  claim 31 , at least one of the two substrates comprising at least one component. 
   
   
       48 . Process according to  claim 31 , the bonding being performed under a controlled atmosphere, under controlled pressure, with or without thermalisation. 
   
   
       49 . Process according to  claim 31 , the temperature at the end of step c) being a heat treatment temperature for reinforcing molecular bonding and/or inducing a fracture in a substrate. 
   
   
       50 . Process according to  claim 31 , also comprising a step:
 d) of reinforcing the bonding by molecular adhesion and/or inducing a fracture in a substrate.   
   
   
       51 . Process according to  claim 50 , step d) being performed by a heat treatment at a temperature above the temperatures of step c). 
   
   
       52 . Process according to  claim 50 , wherein, during step c), the system is brought, for example by one or more temperature levels, to a temperature above 100° C., with step d) being performed at least at a temperature above, or equal, or below this temperature above 100° C. 
   
   
       53 . Process for producing a thin film on a first substrate, comprising a process for producing a bond between the first substrate and a second substrate according to  claim 31 , then a step of thinning the second substrate. 
   
   
       54 . Process according to  claim 53 , the thinning step being performed by chemical and/or mechanical thinning. 
   
   
       55 . Process according to  claim 54 , the thinning step being performed by fracturing the second substrate. 
   
   
       56 . Process according to  claim 54 , the second substrate being pre-implanted by one or more atomic or ionic species in order to create in it a weakness zone. 
   
   
       57 . Process according to  claim 56 , the atomic or ionic species being implanted at a dose above the minimum dose enabling the fracture, which is performed at a temperature below or equal to the temperature normally associated with the minimum dose. 
   
   
       58 . Process according to  claim 57 , the fracture being performed at one or more temperature(s) between 50° C. and 150° C., for at least 3 hours. 
   
   
       59 . Process according to  claim 57 , the ionic species, H + , being implanted in silicon at a dose above 6×10 16  H + ·cm −2 . 
   
   
       60 . Process according to  claim 53 , the thin film obtained having a thickness below 1 μm or 100 nm or 50 nm.