Synaptics’ Under-Display Fingerprint Scanner Inside the VIVO X21 UD Smartphone

Vivo is the first smartphone manufacturer to integrate a fingerprint scanner under the display. Two different versions, one from Synaptics and one from Goodix, were found to have been supplied for the under-display fingerprint scanner integrated into the VIVO X21 UD smartphone.

This reverse costing study provides insight into technological data, manufacturing cost, and selling price of the fingerprint sensor supplied by Synaptics. This scanner uses optical fingerprint technology that allows integration under the display. With a stainless steel support and two flexible printed circuit layers, the Synaptics fingerprint sensor’s dimensions are 6.46 mm x 9.09 mm, with an application specific integrated circuit (ASIC) driver in the flex module. This image sensor is also assembled with a glass substrate where filters are deposited.

The sensor has a resolution of 30,625 pixels, with a pixel density of 777ppi. The module’s light source is providing by the OLED display glasses. The fingerprint module uses a collimator layer correspon-

ding to the layers directly deposited on the die sensor and composed of organic, metallic and silicon layers. This only allows light rays reflected at normal incidence to the collimator filter layer to pass through and reach the optical sensing elements. The sensor is connected by wire bonding to the flexible printed circuit and uses a CMOS process.

This report includes comparisons with the latest Huawei FPC1268 fingerprint touch sensor and a physical comparison with the Goodix Version of Vivo’s fingerprint scanner.

Overview/Introduction

• Executive Summary
• Reverse Costing Methodology

Company Profile

• Synaptics

Physical and Manufacturing Cost Analysis

• Summary of the Physical Analysis
• VIVO X21 UD Fingerprint Scanner Disassembly
  • Fingerprint Scanner Removal
• Synaptics Package Assembly
  • Fingerprint scanner views
  • Fingerprint scanner cross-section
  • Fingerprint scanner patents
• Sensor Die
  • Sensor die view and dimensions
  • Sensor delayering and main blocks
  • Sensor die process
  • Sensor die cross-section
  • Sensor die process characteristic
• ASIC Die
  • ASIC die view and dimensions
  • ASIC delayering and main block
  • ASIC die process
  • ASIC die cross-section
  • ASIC die process characteristic

Synaptics vs Goodix Versions of the Fingerprint Sensors

Sensor Manufacturing Process

• Sensor Die Front-End Process and Fabrication Unit
• ASIC Die Front-End Process and Fabrication Unit
• Final Test and Assembly Unit

Sensor Manufacturing Process

• Summary of the Cost Analysis
• Yields Explanation and Hypotheses
• ASIC Component
  • ASIC die front-end cost
  • Sensor die probe test, thinning and dicing
  • ASIC component cost
• Sensor Module
  • Sensor die front-end cost
  • Collimator filter front-end cost
  • Sensor die probe test, thinning and dicing
  • Sensor die wafer cost
  • Sensor die cost
  • Sensor module cost
• Complete Module Fingerprint
  • Assembled components cost
  • Summary of the assembly
  • Fingerprint component cost

Selling Price

Huawei’s fingerprint sensor vs Vivo’s

REVERSE COSTING WITH

• Detailed photos
• Precise measurements
• Materials analysis
• Manufacturing process flow
• Supply chain evaluation
• Manufacturing cost analysis
• Selling price estimate
• Comparison with Huawei FPC1268 fingerprint scanner and short comparison with the Goodix version