Wafer level hermetic sealing method

Abstract

A device that is hermetically sealed at a wafer level or a method of hermetically sealing a device, which is sensitive to high temperatures or affected by heating cycles. Semiconductor devices are formed on a wafer. A lid wafer is formed. Adhesives are formed in a predetermined position over the wafer and/or the lid wafer. The wafer and the lid wafer are sealed by the adhesives at the wafer level. The sealing may be performed at a low temperature using a solder to protect the devices sensitive to heat. The sealed devices are diced into individual chips. In the wafer level hermetic sealing method, a sawing operation is performed after the devices are sealed. Therefore, the overall processing time is reduced, devices are protected from the effects of moisture or particles, and devices having a moving structure, such as MEMS devices, are more easily handled.

1 . An apparatus with a wafer level hermetic seal comprising: 
 a wafer;    a semiconductor device formed on a device side of the wafer;    a lid wafer with a front side facing the device side of the wafer; and    adhesives which adhere the device side of the wafer and the front side of the lid wafer in a predetermined position, wherein the adhesives seal the device in between the device side of the wafer and the front side of the lid wafer.    
   
   
       2 . The apparatus with the wafer level hermetic seal of  claim 1 , wherein the adhesives are formed of one selected from the group consisting of In, Sn, Ag, Pb, Zn, Au, Bi, Sb, Cd, Ga and Cu, or an alloy of two or more of these metals.  
   
   
       3 . The apparatus with the wafer level hermetic seal of  claim 2 , wherein the adhesives are formed of a material having a fusion point of 100˜300° C.  
   
   
       4 . The apparatus with the wafer level hermetic seal of  claim 2 , wherein the adhesives are formed by deposition or sputtering.  
   
   
       5 . The apparatus with the wafer level hermetic seal of  claim 2 , further comprising adhesive promoters formed over the device side of the wafer and/or the front side of the lid wafer to promote adhesion of the adhesives.  
   
   
       6 . The apparatus with the wafer level hermetic seal of  claim 5 , wherein the adhesives and the adhesive promoters are disposed to align the wafer with the lid wafer.  
   
   
       7 . The apparatus with the wafer level hermetic seal of  claim 5 , wherein the adhesive promoters are formed of metal or polymer.  
   
   
       8 . The apparatus with the wafer level hermetic seal of  claim 2 , wherein electrical connectors are formed on the wafer to transceive an electrical signal.  
   
   
       9 . The apparatus with the wafer level hermetic seal of  claim 8 , wherein the lid wafer comprises a through hole so that the electrical connectors are electrically connected to the outside via an interconnection line passing through the hole.  
   
   
       10 . The apparatus with the wafer level hermetic seal of  claim 2 , wherein the adhesives have a preformed shape.  
   
   
       11 . The apparatus with the wafer level hermetic seal of  claim 2 , wherein the lid wafer formed is a transparent material to exchange an optical signal.  
   
   
       12 . The apparatus with the wafer level hermetic seal of  claim 1 , wherein the adhesives are formed of a material having a fusion point of 100˜300° C.  
   
   
       13 . The apparatus with the wafer level hermetic seal of  claim 1 , further comprising adhesive promoters formed over the device side of the wafer and/or the front side of the lid wafer to promote adhesion of the adhesives.  
   
   
       14 . The apparatus with the wafer level hermetic seal of  claim 13 , wherein the adhesives and the adhesive promoters are disposed to align the wafer with the lid wafer.  
   
   
       15 . The apparatus with the wafer level hermetic seal of  claim 13 , wherein the adhesive promoters are formed of metal or polymer.  
   
   
       16 . The apparatus with the wafer level hermetic seal of  claim 1 , wherein electrical connectors are formed on the wafer to transceive an electrical signal.  
   
   
       17 . The apparatus with the wafer level hermetic seal of  claim 16 , wherein the lid wafer comprises a through hole so that the electrical connectors are electrically connected to the outside via an interconnection line passing through the hole.  
   
   
       18 . The apparatus with the wafer level hermetic seal of  claim 1 , wherein the adhesives have a performed shape.  
   
   
       19 . The apparatus with the wafer level hermetic seal of  claim 1 , wherein the lid wafer formed is a transparent material to exchange an optical signal.  
   
   
       20 . The apparatus with the wafer level hermetic seal of  claim 1 , wherein the adhesives are formed of an organic sealant.