Dual-Thickness Backgrind Tape for Bumped Wafer Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing backgrinding processes face challenges with both thin and thick organic-adhesive backgrind tapes, where thin tapes may not fully cover bumps leading to substrate cracking due to vacuum loss, and thick tapes tend to adhere tightly to the substrate, making residue removal difficult.
Innovation Solution
A dual-thickness backgrind tape design featuring a thinner tape region framing the substrate and a thicker tape region at the periphery, which reduces the risk of substrate cracking by preventing vacuum loss and ensures easy residue removal by providing adequate coverage and compensation during the grinding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick BG tape is used to fully cover bumps, then bump coverage is improved, but adhesive residue removal becomes difficult
Solution Approach 1:
The BG tape is divided into two distinct thickness regions: a first thickness region (thinner) and a second thickness region (thicker). This segmentation allows different portions of the tape to serve different functions - the thinner region provides adequate bump coverage while the thicker region provides vacuum seal, eliminating the need to choose between complete coverage and easy removal.
Solution Approach 2:
Different regions of the BG tape have different thickness properties tailored to their specific functions. The first thickness region (thinner) is optimized for bump coverage and ease of removal, while the second thickness region (thicker) is optimized for vacuum sealing. This local differentiation resolves the contradiction by providing each region with the specific quality it needs.
2Ease of manufacture
If thin BG tape is used to enable easy residue removal, then adhesive residue removal is improved, but substrate cracking risk increases due to vacuum loss
Solution Approach 1:
The BG tape is segmented into two thickness regions where the thinner first thickness region enables easy residue removal while the thicker second thickness region provides the vacuum seal necessary to prevent substrate cracking. This segmentation allows both contradictory requirements to be satisfied in different locations.
Solution Approach 2:
The tape provides different thickness qualities in different locations: the thinner region (first thickness) provides ease of removal where needed, while the thicker region (second thickness) provides vacuum sealing capability at the periphery. This local quality differentiation resolves the contradiction between easy removal and crack prevention.
3Ease of manufacture
If uniform thin BG tape is used, then adhesive residue removal is improved, but vacuum loss occurs leading to substrate cracking
Solution Approach 1:
The uniform tape is segmented into different thickness regions - a thinner first thickness region for easy removal and a thicker second thickness region for vacuum sealing. This segmentation eliminates the need to choose between uniform thinness (easy removal) and uniform thickness (vacuum seal).
Solution Approach 2:
Different regions of the tape have different thickness qualities optimized for their specific functions. The thinner first thickness region provides ease of removal while the thicker second thickness region provides vacuum loss prevention. This local quality approach resolves the contradiction between easy removal and vacuum maintenance.
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
The dual-thickness tape effectively protects bumps during backgrinding, preventing substrate cracking and ensuring no significant adhesive residue remains after de-taping, thus enhancing the backgrinding process efficiency.
Implementation Method 1
the wafer is held by a chuck table that has a porous center chuck portion which allows applying a suction to the taped top side surface of the wafer
Implementation Method 2
the backside of the wafer is ground to a predetermined thickness
Data Source
AI summary
A backgrind (BG) tape includes an adhesive material having a thinner tape region with a first thickness having an area sized to accommodate a substrate therein including an active semiconductor top side surface including a plurality of chips each including at least one transistor and at least one metallization level with bond pads connected to nodes of the transistor and bumps on or coupled to the bond pads. The BG tape also includes a thicker tape region along at least a periphery of the BG tape having a second thickness that is greater than the first thickness.