Semiconductor device and a manufacturing method of the same

Abstract

A semiconductor device having a structure in which the structure is laminated in many stages is made thin. A reforming area is formed by irradiating a laser beam, where a condensing point is put together with the inside of the semiconductor substrate of a semiconductor wafer. Then, after applying the binding material of liquid state to the back surface of a semiconductor wafer by a spin coating method, this is dried and a solid-like adhesive layer is formed. Then, a semiconductor wafer is divided into each semiconductor chip by making the above-mentioned reforming area into a division origin. By pasting up this semiconductor chip on the main surface of the other semiconductor chip by the adhesive layer of the back surface, a semiconductor device having a structure in which the semiconductor device is laminated in many stages is manufactured.

1 . A method of manufacturing a semiconductor device, comprising the steps of:
 (a) providing a wiring substrate including a main surface, a plurality of wirings formed on the main surface, a plurality of first electrodes formed on the main surface, a back surface opposite to the main surface, and a plurality of second electrodes formed on the back surface;   (b) disposing a first adhesive material on the main surface of the wiring substrate;   (c) after the step (b), mounting a first semiconductor chip over the main surface of the wiring substrate via the first adhesive material such that a first rear surface of the first semiconductor chip faces the main surface of the wiring substrate, and such that the wirings formed on the main surface of the wiring substrate are overlapped with the first semiconductor chip via the first adhesive material, and whereby a part of the first adhesive material is overflowed from a first side surface of the first semiconductor chip in a cross-sectional view, and whereby a part of the first side surface of the first semiconductor chip is covered with the part of the first adhesive material, the first semiconductor chip including a first front surface, a plurality of first bonding pads formed on the first front surface, the first rear surface opposite to the first front surface, and the first side surface located between the first front surface and the first rear surface;   (d) after the step (c), stacking a second semiconductor chip over the first front surface of the first semiconductor chip via a second adhesive material formed on a second rear surface of the second semiconductor chip, such that the second rear surface of the second semiconductor chip faces the first front surface of the first semiconductor chip, and such that an entirety of the second semiconductor chip is located inside the first bonding pads, the second semiconductor chip including a second front surface, a plurality of second bonding pads formed on the second front surface, the second rear surface opposite to the second front surface, and a second side surface located between the second front surface and the second rear surface;   wherein the second semiconductor chip is formed by following steps (d 1 )-(d 3 ),
 (d 1 ) providing a semiconductor wafer having a third front surface, and a third rear surface opposite to the third front surface; 
 (d 2 ) forming an adhesive layer on the third rear surface of the semiconductor wafer; and 
 (d 3 ) cutting the semiconductor wafer and the adhesive layer, whereby the second semiconductor chip having the second adhesive material formed on the second rear surface is obtained; and 
   (e) sealing the first semiconductor chip and the second semiconductor chip with a resin;   wherein a thickness of the second adhesive material is thinner than a thickness of the first adhesive material located directly under the first semiconductor chip.   
     
     
         2 . The method according to  claim 1 , further including providing the main surface of the wiring substrate to have a greater surface irregularity as compared to a surface irregularity of the first front surface of the first semiconductor chip. 
     
     
         3 . The method according to  claim 1 , further including forming the second adhesive material using a spin coating method. 
     
     
         4 . The method according to  claim 1 , further including disposing a paste-like material as the first adhesive material on the main surface of the wiring substrate. 
     
     
         5 . The method according to  claim 1 , further including after the step (d) and before the step (e), electrically connecting one of the first bonding pads of the first semiconductor chip with one of the first electrodes of the wiring substrate via a wire. 
     
     
         6 . The method according to  claim 1 , further including after the step (d) and before the step (e), electrically connecting one of the second bonding pads of the second semiconductor chip with one of the first bonding pads of the first semiconductor chip via a wire. 
     
     
         7 . The method according to  claim 1 , further including forming the second adhesive material on the second rear surface of the second semiconductor chip to have a thickness that is less than 10 μm. 
     
     
         8 . The method according to  claim 7 , further including forming the second adhesive material on the second rear surface of the second semiconductor chip to have a thickness that is less than or equal to 5 μm. 
     
     
         9 . The method according to  claim 1 , further including disposing the first adhesive material on the main surface of the wiring substrate to have a thickness that is greater than or equal to 10 μm.