Semiconductor Base Separation via Selective Laser Irradiation
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor devices face issues such as damage to semiconductor chips due to laser irradiation over entire regions, increased manufacturing complexity and cost, and reduced throughput due to small beam spot irradiation, as well as heat-induced degradation of encapsulation resin and via plugs.
Innovation Solution
A method involving the formation of a removal layer and an interconnect layer over a base, with semiconductor chips mounted on the interconnect layer, and selective laser irradiation from the back side using a wavelength transparent to the base in unmounted regions to induce separation originating from the removal layer, reducing damage and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser is irradiated over the entire region right under the object-to-be-separated, then the separation effect is achieved, but the object-to-be-separated may be damaged
Solution Approach 1:
The patent applies local quality by selectively irradiating the laser only to unmounted regions without semiconductor chips, while avoiding mounted regions with chips. This localized approach ensures that the separation function is performed where needed without exposing sensitive semiconductor chips to harmful laser irradiation, thus resolving the contradiction between achieving separation and preventing chip damage.
2Reliability
If laser having a very small beam spot is used for irradiation, then the damage to object-to-be-separated is reduced, but the throughput is worsened
Solution Approach 1:
The patent segments the base into mounted regions and unmounted regions, and applies laser irradiation selectively only to unmounted regions. This segmentation allows the use of a small beam spot for precise, damage-free irradiation while limiting the total irradiated area to only where separation is needed, thereby maintaining both high reliability and acceptable throughput without requiring excessive irradiation time.
3Reliability
If laser is directly irradiated to via plug and interconnect layer, then separation is achieved, but heat conducts to encapsulation resin degrading package reliability
Solution Approach 1:
The patent applies local quality by selectively irradiating only unmounted regions without semiconductor chips, thereby avoiding direct laser irradiation to via plugs and interconnect layers in mounted regions. This prevents excessive heat conduction to the encapsulation resin and maintains package reliability while still achieving separation in unmounted regions where chips are absent.
4Reliability
If intermediate layer including metal reflective layer is added to suppress laser transmission, then damage is suppressed, but the process becomes complicated and cost increases
Solution Approach 1:
The patent applies preliminary action by pre-defining unmounted regions where no semiconductor chips are present, and selectively applying laser irradiation only to these regions. This preliminary identification of safe irradiation zones eliminates the need for additional intermediate layers with metal reflective coatings, as the selective irradiation strategy itself prevents damage without requiring extra protective structures or process steps.
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 approach enhances the reliability of semiconductor devices by minimizing chip damage, simplifies the separation process, and improves production efficiency by allowing for efficient separation of the base from the interconnect layer.
Implementation Method 1
irradiating a laser having a wavelength transparent with respect to the base from the back side thereof
Implementation Method 2
the laser irradiation induces a phase change in the light absorption layer
Implementation Method 3
a gas may be produced in the removal layer, by the selective irradiation of laser
Implementation Method 4
heating and decomposing the removal layer to thereby separate the seed metal layer of the semiconductor device from the support substrate
Data Source
AI summary
Provided is a method for manufacturing a semiconductor device which includes: forming a removal layer over a base (support base); forming an interconnect layer over the removal layer; mounting semiconductor chip(s) over the interconnect layer; and separating the base from the interconnect layer while inducing the separation so as to originate from the removal layer, by irradiating a laser having a wavelength transparent with respect to the support base from the back side thereof, selectively to an unmounted region having no semiconductor chip(s) mounted thereon.