Processing for bonding two substrates

Abstract

The invention relates to a method for bonding two substrates, in particular two semiconductor substrates which, in order to be able to improve the reliability of the process, provides the step of providing a gaseous flow over the bonding surfaces of the substrates The invention also relates to a corresponding bonding equipment

1 .- 15 . (canceled) 
     
     
         16 . A method for forming a composite substrate which comprises:
 providing two substrates with bonding surfaces;   providing a flow of a gas over the bonding surfaces of the substrates; and   bonding the substrates together to form the composite substrate;   wherein the flow of gas is provided between the two substrates until the bonding surfaces come into contact.   
     
     
         17 . The method of  claim 16 , wherein the flow of gas is a laminar flow. 
     
     
         18 . The method of  claim 16 , wherein the flow of gas is provided in a direction that is essentially parallel to the bonding surfaces of the substrates. 
     
     
         19 . The method of  claim 16 , wherein the flow of gas is provided at a temperature of from room temperature to 100° C. 
     
     
         20 . The method of  claim 16 , which further comprises providing a heat treatment of one or both substrates and providing the flow of gas during the heat treatment. 
     
     
         21 . The method of  claim 16 , which further comprises heating the gas such that a heat treatment of one or both the substrates is at least partially carried out using heat from the heated flow of gas. 
     
     
         22 . The method of  claim 21 , wherein the heat treatment of both substrates is completely carried out using heat from the heated flow of gas. 
     
     
         23 . The method of  claim 16 , wherein the gas has a thermal conductivity of greater than 10×10 −3  W/m-K. 
     
     
         24 . The method of  claim 16 , wherein the gas comprises nitrogen or argon. 
     
     
         25 . The method of  claim 16 , wherein the gas comprises a mixture or argon with hydrogen, chlorine or fluorine. 
     
     
         26 . The method of  claim 16 , wherein the flow of gas is carried out over a time period of a few seconds to several minutes. 
     
     
         27 . The method of  claim 16 , wherein the flow of gas is provided in an oxidizing atmosphere. 
     
     
         28 . The method of  claim 27 , wherein the oxidizing atmosphere comprises air or 20% oxygen in nitrogen 
     
     
         29 . The method of  claim 16 , wherein the flow of gas is provided in a dry atmosphere with a low humidity rate. 
     
     
         30 . Equipment for bonding two substrates together to form a composite substrate comprising means for bonding the substrates together and means to provide a laminar flow of gas between the two substrates at least up until the time that the substrate surfaces contact each other for bonding. 
     
     
         31 . The equipment of  claim 30 , wherein the means to provide a flow of gas comprises a ventilation system having one or more gas inlets. 
     
     
         32 . The equipment of  claim 30 , wherein the means to provide a flow of gas comprises an aspiration system having one or more gas inlets. 
     
     
         33 . The equipment of  claim 30 , wherein the means to provide a flow of gas is configured to provide the flow of gas in a direction that is essentially parallel to the substrate surfaces. 
     
     
         34 . The equipment of  claim 30 , wherein the means to provide a flow of gas further comprises means for heating the gas wherein the heating means is capable of heating the gas to at least 100° C.