Semiconductor Substrate Dicing with Rear Grooves and Protective Film
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Solution Overview
Problem
Conventional semiconductor manufacturing methods face challenges in attaching die attach films (DAF) to substrates, leading to issues such as increased adhesive force due to heating, peeling difficulties, sagging, and the generation of cutting whiskers during dicing, which can cause chipping and short circuits.
Innovation Solution
A manufacturing method involving half-cutting the substrate from the rear surface with the film attached, followed by attaching a protective member and forming stepped grooves through dicing, which supports the film during cutting and reduces the occurrence of cutting whiskers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the substrate is heated to increase adhesive force during DAF attachment, then the adhesive strength is improved, but the film sags and positioning accuracy deteriorates
Solution Approach 1:
The substrate is heated in advance before DAF attachment to increase adhesive strength, allowing the film to be firmly bonded. The heating is completed prior to the attachment process, so the temperature is maintained at an optimal level during bonding without causing sagging during the actual attachment operation.
Solution Approach 2:
The heating process is applied periodically or in stages - heating the substrate before attachment to enhance adhesive properties, then maintaining or reducing temperature during attachment to prevent film sagging. This periodic temperature control resolves the contradiction between needing high temperature for strength and low temperature for precision.
2Productivity
If dicing is performed from the front surface to create grooves, then the substrate is divided into units, but cutting whiskers are generated causing chipping and short circuits
Solution Approach 1:
Instead of dicing from the front surface, the method performs half-cutting from the rear surface of the substrate. This inverted approach allows the blade to cut through the substrate thickness without exposing the front surface to cutting whiskers, thereby preventing chipping and short circuits while maintaining efficient substrate division.
Solution Approach 2:
The dicing process is divided into two stages: first, half-cutting from the rear surface to create a groove without completing the cut; second, finishing the cut from the front surface. This segmentation allows the harmful cutting whiskers to be generated only in the groove area rather than on the device surface, maintaining both productivity and reliability.
3Area of stationary object
If the film is attached to the entire rear surface including outer peripheral portions, then coverage is maximized, but peeling occurs during handling and processing
Solution Approach 1:
The film attachment is differentiated by region: the outer peripheral portion of the rear surface has reduced or no film coverage, while the inner peripheral portion maintains full film coverage. This local quality variation prevents peeling at the vulnerable edges while preserving the bonding strength and coverage needed in the central device area.
Data Source
AI summary
In a manufacturing method of a semiconductor device including a substrate having a front surface and a rear surface, and a film attached to the rear surface, the film is attached on the rear surface, a rear surface side groove is provided by half-cutting the substrate from the rear surface together with the film, a protective member is attached to the film after the rear surface side groove is provided, and a front surface side groove connected to the rear surface side groove is provided by dicing the substrate from the front surface after the protective member is attached.