Semiconductor Bond Pad Marker for Optical Alignment Contrast
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor dies with highly reflective bond pads and high metallization density around bond pads are difficult to optically distinguish during alignment, testing, and bonding processes due to lack of contrast.
Innovation Solution
Incorporating an optical detection marker in the form of a groove that exposes a metal layer with different contrast from the bond pad metallization, allowing the underlying metal layer to be optically visible, thereby enhancing pad recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly reflective bond pads and high metallization density are used, then electrical contact performance is improved, but optical distinguishability deteriorates
Solution Approach 1:
The bond pad structure is segmented into multiple metallization layers with different optical properties. The top bond pad metallization provides electrical contact, while the underlying barrier metallization layer provides optical contrast when exposed through the groove, allowing both electrical performance and optical detectability to coexist.
Solution Approach 2:
Different regions of the contact pad structure are given different properties: the top bond pad metallization is highly reflective for electrical contact, while the exposed barrier metallization in the groove region provides contrasting optical appearance. This local differentiation allows the structure to serve dual purposes of electrical conduction and optical detection.
2Reliability
If high metallization density around bond pads is used, then electrical connectivity is improved, but optical contrast deteriorates
Solution Approach 1:
The metallization structure is divided into functionally distinct layers: the top bond pad metallization for electrical connectivity and the underlying barrier metallization for optical contrast. The groove exposes the barrier layer to provide visual detection capability while the top layer maintains electrical connectivity.
Solution Approach 2:
The barrier metallization layer acts as an intermediary element between the highly reflective bond pad metallization and the substrate. When exposed through the groove, it provides the optical contrast needed for detection while the bond pad metallization above it maintains the electrical connectivity function.
3Difficulty of detecting and measuring
If optical detection marker is added, then optical detectability is improved, but manufacturing complexity increases
Solution Approach 1:
The optical detection marker function is merged with the existing barrier metallization layer that is already part of the contact pad structure. By exposing this existing layer through a groove, the patent creates an optical marker without adding separate materials or complex structures, thus improving detectability while minimizing manufacturing complexity.
Solution Approach 2:
The barrier metallization layer serves multiple functions: it provides electrical barrier properties for the contact pad and simultaneously serves as an optical detection marker when exposed. This multi-functionality eliminates the need for separate marker structures, reducing manufacturing complexity while improving optical detectability.
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
Facilitates clear optical detection of bond pads by creating a visible contrast with the underlying metal layer, improving alignment and testing processes.
Implementation Method 1
a first barrier metallization below the first bond pad metallization, the first barrier metallization having a different contrast than the first bond pad metallization
Data Source
AI summary
A semiconductor die includes: a semiconductor substrate; a first contact pad structure above the semiconductor substrate, the first contact pad structure including a metal contact pad configured for electrical contact and a metal layer adjoining an underside of the metal contact pad and jutting out beyond an edge of the metal contact pad; and a first optical detection marker in a periphery of the first contact pad structure and having a different contrast than the metal contact pad. The first optical detection marker includes a region of the metal layer that is adjacent to the edge of the metal contact pad and unobstructed by the metal contact pad so as to be optically visible in a plan view of the semiconductor die. A method of producing the semiconductor die is also described.