Wafer Dicing Using Passivation Film as Plasma Etch Mask
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Solution Overview
Problem
Current device chip manufacturing methods using plasma etching are costly due to the need for resist masks and cannot process die attach films, requiring separate removal methods for the die attach film along division lines.
Innovation Solution
A method involving a passivation film removal step, wafer supporting with a die attach film and dicing tape, followed by plasma etching using fluorine-based and oxygen-based gases to divide the wafer and remove the die attach film, eliminating the need for resist masks and separate die attach film removal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plasma etching using fluorine-based gas is used to cut the wafer, then the occurrence of chipping is suppressed and die strength is improved, but the die attach film cannot be processed and requires separate removal
Solution Approach 1:
The patent changes the gas parameter from fluorine-based gas to oxygen-based gas to enable processing of the die attach film. Oxygen-based plasma etching selectively removes the die attach film material while preserving the device chips, solving the limitation of fluorine-based gas that cannot process die attach films.
Solution Approach 2:
The patent segments the plasma etching process into two distinct steps: first using fluorine-based gas to cut the wafer and create grooves, then using oxygen-based gas to remove the die attach film. This segmentation allows each gas type to perform its specialized function without interference.
2Ease of manufacture
If photolithography is used to form a resist mask for plasma etching, then the wafer can be processed, but the manufacturing cost increases
Solution Approach 1:
The passivation film serves a dual function: it protects the device chips during processing and acts as a self-aligned mask for the plasma etching process. The grooves created in the passivation film automatically define the etching regions without requiring additional resist mask materials or photolithography steps.
Solution Approach 2:
The passivation film is given multiple functions: it protects the device chips from damage, defines the division lines through groove formation, and serves as the etching mask. This multi-functionality eliminates the need for separate resist mask layers and reduces manufacturing complexity.
3Productivity
If a cutting apparatus is used to cut the wafer along division lines, then the wafer can be divided into device chips, but mechanical crushing causes chipping and reduces die strength
Solution Approach 1:
The patent replaces the mechanical cutting system with a plasma etching system. Instead of using a rotating cutting blade that mechanically crushes and chips the wafer, the invention uses fluorine-based plasma to chemically etch grooves along the division lines, completely eliminating mechanical contact and associated damage.
Solution Approach 2:
The patent utilizes the phase transition properties of fluorine-based gas to plasma. The gas is ionized into plasma state, which then chemically reacts with the wafer material to create precise grooves without mechanical contact, avoiding the chipping and damage caused by mechanical cutting.
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 method allows for the cost-effective manufacturing of device chips with attached die films by using the passivation film as a mask for plasma etching, reducing the need for additional processing steps and enhancing die strength without mechanical damage.
Implementation Method 1
a laser beam 2a having an absorption wavelength is applied to the wafer 11 along each division line 13 to thereby form a groove 11c on the front side 11a of the wafer 11 along each division line 13, so that the passivation film 17 is removed along each division line 13
Implementation Method 2
performing plasma etching using a fluorine-based gas to the front side of the wafer in the condition where the passivation film is used as a mask after performing the passivation film removing step and the wafer supporting step, thereby dividing the wafer into the individual device chips along the division lines
Implementation Method 3
performing plasma etching using an oxygen-based gas to the front side of the wafer in the condition where the passivation film is used as a mask after performing the wafer dividing step, thereby removing a part or the whole of the die attach film along each division line
Data Source
AI summary
A device chip manufacturing method includes a passivation film removing step of removing a passivation film along each division line, a wafer dividing step of performing plasma etching using a fluorine-based gas to the front side of a wafer in the condition where the passivation film is used as a mask, thereby dividing the wafer along the division lines, and a die attach film removing step of performing plasma etching using an oxygen-based gas to the front side of the wafer in the condition where the passivation film is used as a mask, thereby removing a part or the whole of a die attach film along each division line.