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SP19456 - ams' d-ToF Proximity Sensor_1

ams’ Direct Time-of-Flight Detection SPAD-Based Proximity Sensor

Product code
EUR 6990
Mobile & Consumer
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The first ams d-ToF proximity sensor based on Single Photon Avalanche Diode (SPAD) technology in the Huawei Mate 20 Pro.

STMicroelectronics was the first company to provide Single Photon Avalanche Diode (SPAD) technology for proximity sensing. Back in 2016, Apple started to implement this technology for its high-end iPhone 7 Plus. At this time, the phone-making Original Equipment Manufacturers (OEMs) were looking for highly sensitive proximity sensors requiring low photon incidence to work. Several companies have followed this path and have developed their own SPAD technology. This year, ams started mass production of its proximity sensors based on SPAD technology and offer the solution to several customers. The very first customer is Huawei, with ams supplying a custom proximity sensor in the Huawei Mate 20 Pro. Following this, ams is expected to gain increasing market share with several design wins in other OEMs’ flagships this year.

 SP19456 - ams' d-ToF Proximity Sensor_1

In the Huawei Mate 20 Pro, the front optical hub is packaged in one metal enclosure featuring several cameras and sensors. The complete system features a red/green/blue (RGB) camera module, an ambient light sensor, a near-infrared (NIR) global shutter (GS) camera module, a flood illuminator, a proximity sensor and a dot projector.

This report focusses on analyzing the proximity sensor. Located in the front around the main speaker, the proximity sensor is contained in a Land Grid Array (LGA) package.  The device is probably a custom version of the new TMF8701 component made specifically for Huawei, and is the first on the market from ams. The component includes a SPAD detector featuring a 15 µm-wide SPAD, with 128 pixel resolution, and a single Vertical Cavity Surface Emitting Laser (VCSEL). The structure uses innovative optical LGA packaging with polymer lenses produced using a transfer molding process.

This complete analysis of the proximity sensor includes detailed analyses of the SPAD detector and the VCSEL, along with a cost analysis and price estimation for the module. It also includes a physical and technical comparison with the custom proximity sensor from STMicroelectronics in the Apple iPhone 8 and iPhone X/XR/XS.

SP19456 - ams' d-ToF Proximity Sensor_3SP19456 - ams' d-ToF Proximity Sensor_4SP19456 - ams' d-ToF Proximity Sensor_2
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Overview /Introduction

ams Company Profile and Time of Flight Technology

Huawei Mate 20 Pro Teardown

Physical Analysis

  • Physical Analysis Methodology
  • Package
    • View and dimensions
    • Package opening and wire bonding process
    • Package cross-section: adhesives, PCB, lens, FOV
  • VCSEL Die
    • View and dimensions
    • Wire bonding, cavity
    • Cross-section
    • Process characteristics
  • ASIC Die
    • View, dimensions and marking
    • Die overview: filters, active area, SPAD technology
    • Die delayering, main blocks ID and process
    • Cross-section: filters, metal layers, SPADs
    • Process characteristics

Physical Comparison with STMicroelectronics’ Custom Proximity Sensors

  • Package, Functions, FOV, Optical Blocking Package, ASIC and VCSEL, SPADs

Manufacturing Process Flow

  • Overview
  • ASIC Front-End Process
  • VCSEL Front-End Process
  • ASIC Wafer Fabrication Unit
  • VCSEL Wafer Fabrication Unit
  • Packaging Process Flow
  • Final Assembly Unit

Cost Analysis

  • Cost Analysis Overview
  • The Main Steps Used in the Economic Analysis
  • Yield Hypotheses
  • ASIC and VCSEL Die Cost
    • Front-end cost
    • Back-end: tests and dicing
    • Wafer and die cost
  • Component
    • Packaging cost
    • Packaging cost per process steps
    • Component cost

Estimated Price Analysis

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