Titanium Oxide Layer for Semiconductor Package Marking
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Solution Overview
Problem
Conventional semiconductor package marking methods using laser processing on the encapsulant result in shallow uneven portions and reduced visibility due to lower laser output power to avoid heat influence on the semiconductor device, leading to degraded mark visibility and increased overall package thickness.
Innovation Solution
A semiconductor package structure incorporating a titanium oxide identification film with a first section containing divalent titanium oxide and a second section containing tetravalent titanium oxide, formed by laser irradiation, which changes color from black to white, ensuring improved visibility and EMI mitigation, and can be formed using existing equipment like sputtering and laser processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser processing is performed on the encapsulant to form a mark, then the mark is formed on the semiconductor package, but the visibility is degraded due to shallow uneven portions caused by lower laser output power
Solution Approach 1:
A titanium oxide layer is introduced as an intermediary material between the encapsulant and the mark formation process. This layer absorbs laser energy and undergoes color change (from black to white) at lower temperatures, enabling mark formation without directly heating the encapsulant and semiconductor device, thus resolving the contradiction between mark visibility and heat influence
Solution Approach 2:
The patent changes the physical-chemical parameters of the marking process by using laser irradiation to induce color change in titanium oxide from divalent (black) to tetravalent (white) state. This allows mark formation through optical property change rather than mechanical unevenness, improving visibility without requiring high laser power that would cause harmful heat influence
2Reliability
If lower laser output power is used to avoid heat influence on the semiconductor device, then heat damage is reduced, but the mark visibility is degraded due to shallow uneven portions
Solution Approach 1:
The patent utilizes color change properties of titanium oxide under laser irradiation. The titanium oxide layer changes from black (divalent) to white (tetravalent), creating high-contrast visible marks. This color change mechanism allows reliable mark formation with low laser power, simultaneously achieving both heat damage prevention and improved mark visibility
3Manufacturing precision
If laser processing is performed on the encapsulant, then the mark is formed, but the overall package thickness is increased
Solution Approach 1:
The marking function is segmented from the encapsulant structure and assigned to a separate titanium oxide layer. This layer is formed as a thin film through sputtering and can be selectively removed or modified by laser irradiation to form marks. This segmentation allows mark formation without adding significant thickness to the overall package, as the titanium oxide layer itself is very thin
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 solution enhances mark visibility and reduces the overall package thickness by allowing higher laser output for marking, mitigating heat influence on the semiconductor device and providing effective EMI shielding without degrading the encapsulant.
Implementation Method 1
a first section containing divalent titanium oxide and a second portion containing tetravalent titanium oxide
Implementation Method 2
can be formed using existing equipment like sputtering and laser processing
Data Source
AI summary
A semiconductor package includes a substrate, a semiconductor element disposed on the substrate, an encapsulating layer covering side surfaces and a top surface of the semiconductor element, an electromagnetic shield layer covering side surfaces of the substrate and side surfaces and a top surface of the encapsulating layer, and a titanium oxide layer formed above a top surface of the electromagnetic shield layer, and including a first portion containing divalent titanium oxide and a second portion containing tetravalent titanium oxide.