Lead Frame Through Holes for Tape Position Detection
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Solution Overview
Problem
Existing methods for examining the position of a tape attached to a die pad in semiconductor devices using transmitted or reflected light are ineffective due to the die pad's non-transmissive nature and reduced light reflection, leading to difficulties in accurately determining the tape's position and potentially reducing the positional accuracy of the semiconductor chip.
Innovation Solution
A lead frame design that includes a die pad with through holes formed in the outer periphery of a film-like member, allowing for the detection of the tape's position using transmitted light, where the tape is attached at an appropriate position relative to the through holes, ensuring accurate placement and bonding of the semiconductor chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmitted light examination is used to detect the tape position on the die pad, then the detection capability is improved, but the method is ineffective because the die pad does not transmit light
Solution Approach 1:
The die pad is segmented by forming through holes in it, creating openings that allow transmitted light to pass through. This segmentation enables the examination system to detect the tape position by observing light transmission through the through holes, resolving the contradiction between wanting to use transmitted light for accurate detection and the die pad's non-transmissive nature.
2Measurement precision
If reflected light examination is used to detect the tape position, then the detection is possible due to reduced reflection at the tape, but the accuracy is reduced because fine scratches or tone unevenness on the die pad surface also reduce reflection
Solution Approach 1:
The through holes act as an intermediary structure that enables transmitted light examination. By creating these openings, the system can use light transmission as a mediator to detect the tape position accurately, avoiding the problems associated with reflected light examination where surface imperfections interfere with detection accuracy.
3Strength
If the die pad is made as a solid sheet-like structure, then the structural integrity is maintained, but the ability to transmit light for examination is lost
Solution Approach 1:
The die pad maintains solid structure in most areas to preserve structural integrity, but locally has through holes formed in it to enable light transmission for examination. This local quality change allows the die pad to simultaneously maintain its mechanical strength while enabling accurate tape position detection through transmitted light examination.
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 through holes enable precise detection of the tape's position using transmitted light, enhancing the accuracy of the tape's attachment and preventing reductions in semiconductor chip positional accuracy during the manufacturing process.
Implementation Method 1
a through hole that penetrates through the die pad is formed in an area in which a reference point or a reference line of the tape that is attached to an appropriate position is located
Implementation Method 2
in an examination using the reflected light, reflection of light at the position of the tape is reduced as compared to a surrounding metal portion
Data Source
AI summary
A lead frame includes a die pad that includes a mounting surface for a semiconductor chip, and a film-like member that is arranged on the mounting surface of the die pad. The die pad includes a through hole that is formed in an area that includes an outer periphery of the film-like member.