Optical Chip Rear Hollow Structure for Stable Planar Support

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing optical chip technology faces issues with mechanical strength and stability due to fragile silicon oxide suspension beams, limited flexibility in metal routing and waveguide design, and interference from adhesive filling in advanced packaging processes, which affect performance and reliability.

Innovation Solution

The optical chip design includes a rear substrate hollowed structure with a planar support system formed by stacked oxide layers, eliminating the need for front-side etching and allowing for flexible functional structure arrangements, enhancing mechanical strength and process compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If front substrate hollowing is used to improve component performance, then optical component performance is improved, but mechanical strength and stability deteriorate due to fragile silicon oxide suspension beams

Engineering Contradiction:
Improveoptical component performanceVSAvoidmechanical strength and stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent inverts the conventional approach by moving the substrate hollowing structure from the front side to the rear side of the optical chip. This inversion allows the front side to maintain a complete, solid substrate structure for mechanical support, while the rear side hollowing provides the necessary optical performance benefits without compromising front-side structural integrity.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions from two-dimensional planar support to three-dimensional spatial arrangement by creating a hollowed structure on the rear substrate. This dimensional change allows the support structure to extend vertically through multiple layers (first oxide layer, front functional structure layer, second oxide layer) while maintaining mechanical strength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If etched window is used for substrate hollowing, then substrate hollowing is achieved, but flexibility of metal routing and waveguide design is limited

Engineering Contradiction:
Improvesubstrate hollowing capabilityVSAvoidmetal routing and waveguide design flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent inverts the location of the hollowing operation from the front side to the rear side, which eliminates the need for etched windows in the front substrate. This inversion restores full flexibility to front-side metal routing and waveguide design, as these structures can now extend to the chip edge without being constrained by etched window boundaries.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If etched window is formed for substrate hollowing, then substrate hollowing is completed, but process compatibility deteriorates due to adhesive filling interference in advanced packaging

Engineering Contradiction:
Improvesubstrate hollowing completionVSAvoidprocess compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent resolves the process compatibility issue by inverting the hollowing location to the rear side. This eliminates the conflict between etched windows and adhesive filling processes, as the adhesive can now uniformly fill the entire front substrate surface without being blocked or interfered with by etched window structures, thereby enabling successful advanced packaging processes.

Inventive Principle:
Principle #13The other way round (Inversion)

4Ease of manufacture

If thin and long suspension beam is used to support front structure, then substrate hollowing is achieved, but mechanical strength and stability deteriorate

Engineering Contradiction:
Improvesubstrate hollowing structureVSAvoidmechanical strength and stability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent inverts the hollowing location from front to rear, which eliminates the need for thin and long suspension beams to support the front structure. The front substrate remains solid and continuous, providing inherent mechanical strength and stability without requiring fragile suspension beam structures.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent creates a three-dimensional hollowed structure on the rear substrate that extends vertically through multiple functional layers. This dimensional approach provides structural support through vertical stacking rather than relying on horizontal suspension beams, thereby improving mechanical strength.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4692874A1Optical chip, optical module and optical communication device
Publication Date: 2026.02.11 HUAWEI TECH CO LTD
  • EP4692874A1 patent drawingFigure 1~3
  • EP4692874A1 patent drawingFigure 4~5
  • EP4692874A1 patent drawingFigure 6~7

AI summary

An optical chip (10, 10a, 10b, 10c, 10d, 10e, 10f, 10g), an optical module (100), and an optical communication device (1000) are provided. The optical chip (10, 10a, 10b, 10c, 10d, 10e, 10f, 10g) includes a substrate (1), a first oxide layer (2), a front functional structure layer, and a second oxide layer (4) that are sequentially stacked. The front functional structure layer of the optical chip (10, 10a, 10b, 10c, 10d, 10e, 10f, 10g) covers a first region (21) on a first surface of the first oxide layer (2). The second oxide layer (4) covers the front functional structure layer and a region other than the first region (21) on the first surface of the first oxide layer (2). A rear substrate hollowed structure (11, 11a, 11b, 11c) is disposed on the substrate (1) of the optical chip (10, 10a, 10b, 10c, 10d, 10e, 10f, 10g). An inner surface of the substrate hollowed structure (11, 11a, 11b, 11c) extends to a second region (12) on a first surface of the substrate (1). The second region (12) includes a region that is opposite to the front functional structure layer, and a process window (13, 13a, 13b, 13c) of the substrate hollowed structure (11, 11a, 11b, 11c) is formed on a second surface of the substrate (1). A process window structure for hollowing the substrate (1) is disposed on a rear side of the optical chip (10, 10a, 10b, 10c, 10d, 10e, 10f, 10g), and the second oxide layer (4) and the first oxide layer (2) collectively form planar support, effectively improving mechanical strength and stability of the structure. In addition, another front functional structure may be arranged according to a requirement, and there is good process compatibility.