Stack-Type Semiconductor Device Adhesive Film Dicing and Bonding
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Solution Overview
Problem
The existing methods for manufacturing stack-type semiconductor devices face challenges in preventing insulation failure and short circuits due to bonding wires coming into contact with upper semiconductor elements, particularly when using low-viscosity adhesive layers, which also lead to issues like adhesive sticking out, deformation of bonding wires, and unfilled resin portions, affecting the reliability of the semiconductor device.
Innovation Solution
A method involving a complex film formed by integrating a dicing film and an adhesive film with specific thickness and elastic modulus ranges, applied on the rear surface of semiconductor wafers, is used to prevent bonding wire contact. The adhesive layer is thermally cured while softening with radiant heat from the first semiconductor element and bonding wires, ensuring the wires are taken into the adhesive layer, thus maintaining the layered form and preventing contact with the upper element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-viscosity adhesive layer is used to facilitate bonding wire insertion, then wire deformation is prevented, but adhesive sticks out from end faces and layered form deteriorates
Solution Approach 1:
The patent dynamically adjusts the adhesive layer's viscosity through controlled heating. During bonding wire insertion, the heated adhesive layer has low viscosity for easy wire placement. After wire insertion, the adhesive layer cools and returns to high viscosity, maintaining the layered form and preventing adhesive extrusion.
Solution Approach 2:
The patent performs preliminary heating of the adhesive layer before bonding wire insertion to reduce its viscosity. This preliminary action prepares the adhesive layer in advance to facilitate smooth wire insertion without causing adhesive to stick out or deform the layered structure.
2Strength
If adhesive film is affixed on semiconductor wafer rear surface, then bonding is enabled, but picking up semiconductor element from dicing film becomes difficult
Solution Approach 1:
The patent segments the adhesive film from the dicing film by forming the adhesive layer only on the rear surface of the semiconductor wafer. After dicing and bonding wire formation, the adhesive film remains attached to the semiconductor element while the dicing film can be easily removed, facilitating element pickup without compromising bonding strength.
Solution Approach 2:
The patent uses the semiconductor wafer rear surface as an intermediary substrate to affix the adhesive film. This allows the adhesive film to be positioned precisely on the semiconductor element during dicing, enabling strong bonding while the dicing film serves as a temporary carrier that can be easily removed after bonding wire formation.
3Productivity
If conventional manufacturing processes are applied to low-viscosity thick adhesive layer, then production efficiency is maintained, but various failures occur including insulation failure and short circuit
Solution Approach 1:
The patent introduces a temperature parameter change step in the manufacturing process. By heating the adhesive layer to a predetermined temperature before bonding wire formation and then controlling the heating during sealing resin formation, the process maintains conventional manufacturing efficiency while preventing insulation failure and short circuit through optimized adhesive viscosity control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the success rate of affixing and picking up semiconductor elements, reduces failure incidence in the dicing process, and improves the reliability of the stack-type semiconductor device by preventing insulation failure and short circuits, while allowing for further thinning and higher manufacturing yields.
Implementation Method 1
softening or melting the adhesive layer by radiant heat from the heated first semiconductor element and by heat transferred from the first bonding wire
Implementation Method 2
softening or melting the adhesive layer by radiant heat from the heated first semiconductor element and by heat transferred from the first bonding wire
Implementation Method 3
placing the first semiconductor element bonded on the substrate, on a stage having a heating mechanism to heat the first semiconductor element
Implementation Method 4
applying a pressure to the second semiconductor element while continuing the heating by the heating mechanism, and thermally curing the adhesive layer to bond the first semiconductor element and the second semiconductor element
Data Source
AI summary
A first semiconductor element is bonded on a substrate. A complex film formed of integrated dicing film and adhesive film is affixed on a rear surface of a semiconductor wafer which is to be second semiconductor elements, the dicing film having a thickness within a range of not less than 50 μm nor more than 140 μm and a room temperature elastic modulus within a range of not less than 30 MPa nor more than 120 MPa, and the adhesive film having a thickness of 30 μm or more and a room temperature elastic modulus before curing within a range of not less than 500 MPa nor more than 1200 MPa. The semiconductor wafer together with the adhesive film is divided into the second semiconductor elements. The second semiconductor element is picked up from the dicing film to be bonded on the first semiconductor element.