High-Frequency Electronic Device Impedance Matching via Grounded Conductor
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Solution Overview
Problem
In high-frequency device substrates, the characteristic impedance at coupling parts between conductor lines and signal lines is not adequately adjusted, leading to deteriorated operation characteristics, especially at frequencies above 100 GHz.
Innovation Solution
The electronic device incorporates a semiconductor chip with a first grounded layer, a first wiring layer forming a transmission line with a predetermined characteristic impedance, a mold resin, an insulating layer, a second grounded layer, and a second wiring layer with specific line widths and a via that couples these layers, along with a grounded conductor within the insulating layer to maintain impedance matching across microstrip lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the characteristic impedance is not adjusted at coupling parts between conductor lines and signal lines, then the device complexity is reduced, but the operation characteristics deteriorate at high frequencies (100 GHz to several hundreds of GHz)
Solution Approach 1:
The patent applies local quality by creating a grounding conductor with variable width specifically at the coupling part between the conductor line and signal line. The grounding conductor has a first width in the coupling region and a second width (different from the first width) in other regions, allowing localized impedance adjustment without changing the entire grounding structure. This resolves the contradiction by improving operation characteristics at high frequencies through localized modification rather than global structural changes.
2Reliability
If a grounding conductor with variable width is introduced to adjust characteristic impedance, then the operation characteristics improve, but the manufacturing precision requirements increase
Solution Approach 1:
The patent implements parameter changes by varying the width of the grounding conductor along its length. The grounding conductor has a first width when viewed from the conductor line side and a second width (different from the first width) when viewed from other directions, particularly at coupling regions. This parameter variation allows continuous impedance adjustment to achieve optimal impedance matching (e.g., 50 ohms) without requiring extremely tight manufacturing tolerances, as the design can compensate for variations through the width modulation.
Data Source
AI summary
An electronic device includes a semiconductor device including a semiconductor chip, a first grounded layer formed on a surface of the semiconductor chip, a mold resin arranged on a side of the semiconductor device, an insulating layer arranged over the semiconductor device and the mold resin, a second grounded layer formed between the semiconductor device and the insulating layer, and the resin mold and the insulating layer, a second wiring layer formed over the insulating layer and includes a first area disposed at a part overlapping with the second grounded layer and a second area disposed on a side of an end part of the second grounded layer, a via that couples the first wiring layer and the second area of the second wiring layer, and a grounded conductor formed inside the insulating layer at a position overlapping with the second area of the second wiring layer.