Thin-Film Encapsulation for Optoelectronic Semiconductors
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Solution Overview
Problem
Existing thin-film encapsulation methods struggle to effectively encapsulate optoelectronic semiconductor bodies with topographical unevenness, leading to structural weak points and inadequate sealing against aggressive liquids and gases.
Innovation Solution
A thin-layer encapsulation comprising a PVD layer and a CVD layer, where the CVD layer is applied to fill structural weak points in the PVD layer, forming a hermetically sealed interface suitable for surfaces with high aspect ratios, and optionally including directional etching to ensure precise filling of gaps, while allowing for the use of insulating materials to achieve an electrically conductive encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PVD layer is deposited on a surface with topographical unevenness, then the surface can be covered, but structural weak points and gaps form at edges and uneven areas leading to inadequate sealing
Solution Approach 1:
The patent uses a composite encapsulation structure combining PVD and CVD layers. The PVD layer provides initial coverage and electrical conductivity, while the CVD layer fills structural weak points and provides hermetic sealing. This composite approach leverages the complementary strengths of both deposition methods to achieve complete encapsulation of topographical unevenness.
Solution Approach 2:
The encapsulation process is segmented into two distinct stages: first depositing a PVD layer for base coverage and conductivity, then adding a CVD layer specifically to seal gaps and weak points. This segmentation allows each layer to perform its optimized function without compromising the other.
2Area of stationary object
If the surface has high aspect ratio structures, then more encapsulation coverage is needed, but conventional methods cannot effectively fill gaps and edges
Solution Approach 1:
The patent changes the deposition parameters by switching from PVD to CVD methodology. CVD processes operate at different temperature and pressure conditions that enable material to flow and conformally coat vertical sidewalls and high aspect ratio structures, achieving complete coverage where PVD fails.
Solution Approach 2:
The CVD layer acts as an intermediary that bridges the gaps and weak points created by the PVD deposition on high aspect ratio structures. It mediates the sealing function by filling edges and gaps that the PVD layer cannot cover, achieving hermetic sealing.
3Reliability
If insulating materials are used in the encapsulation layer, then hermetic sealing is improved, but electrical contact capability is lost
Solution Approach 1:
The patent applies different material properties to different regions and layers. The PVD layer uses conductive materials for electrical contact areas, while the CVD layer uses insulating materials for hermetic sealing regions. This local differentiation of material quality allows both electrical and sealing functions to coexist.
Solution Approach 2:
The encapsulation structure is segmented into functional zones: the PVD layer handles electrical conductivity and initial coverage, while the CVD layer handles hermetic sealing. This functional segmentation resolves the contradiction between electrical contact and hermetic sealing requirements.
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 provides a hermetically sealed, gas-tight encapsulation suitable for surfaces with high aspect ratios, effectively preventing diffusion of atoms or ions and ensuring reliable protection against environmental influences, including liquids, while allowing for electrical contact and mechanical protection of sensitive metallic elements.
Implementation Method 1
A PVD layer which was deposited by means of a PVD method
Implementation Method 2
a CVD layer which was deposited by means of a CVD method
Data Source
Figure 1A~1C
Figure 2
Figure 3A~3C
AI summary
A thin-film encapsulation (11) for an optoelectronic semiconductor body comprising a PVD layer (6) deposited by means of a PVD method and a CVD layer (10) deposited by means of a CVD method is specified. An optoelectronic semiconductor body comprising a thin-film encapsulation and a method for producing a thin-film encapsulation are furthermore specified.