IC Test and Measurement - Wafer Preparation

Integrated Circuits Overview

• Integrated Circuits (IC) consist of a collection of electronic components and their wiring, compacted onto a tiny slice of monocrystalline semiconductor material.
• Silicon, the primary material used for ICs, ranks as the second most abundant element on Earth, following Oxygen.

IC Manufacturing Process Stages

• The IC manufacturing process includes:
  • Wafer Preparation
  • Wafer Fabrication
  • Wafer Sort
  • Integrated Circuit Assembly
  • Final Test

Wafer Preparation

• Wafer preparation is fundamental for IC production, focusing on silicon wafers as the main material.

Types of Silicon Crystals

• Monocrystalline Silicon:
  • Characterized by a continuous and unbroken crystal lattice with no grain boundaries.
• Polycrystalline Silicon:
  • Exhibits a more disordered structure, opposite the monocrystalline characteristics.

Subprocesses of Wafer Preparation

• Key subprocesses involve:
  • Zone Refining
  • Czochralski Pulling Technique
  • Ingot Surface Grinding
  • Ingot Slicing
  • Wafer Scrubbing
  • Wafer Rinsing
  • Wafer Final Polish
  • Resistivity Check and Inspection

Zone Refining

• Also known as zone melting or floating zone process, this technique allows for the purification of silicon.
• A narrow molten zone is moved along the crystal, melting impure solids at its leading edge and leaving behind purer material as it solidifies.

Czochralski Pulling Technique

• A crystal growth method used to produce monocrystalline semiconductors.
• Named after Jan Czochralski, who discovered this process in 1916 during experiments on the crystallization rates of metals.

Integrated Circuit Overview

• Integrated Circuit (IC) consists of electronic components and interconnections etched onto a small slice of monocrystalline semiconducting material.
• Silicon is the primary material for ICs and is the second most abundant element on Earth after oxygen.

IC Manufacturing Process

• Wafer Preparation is the first step, followed by Wafer Fabrication, Wafersort, Integrated Circuit Assembly, and Final Test.

Wafer Preparation

• Focuses on preparing silicon wafers.
• Essential sub-processes include:
  • Zone Refining
  • Czochralski Pulling Technique
  • Ingot Surface Grinding
  • Ingot Slicing
  • Wafer Scrubbing
  • Wafer Rinsing
  • Wafer Final Polish
  • Resistivity Check and Inspection

Types of Crystals

• Monocrystalline:
  • Continuous crystal lattice without grain boundaries.
• Polycrystalline:
  • Comprises multiple grains, contrasting with monocrystalline characteristics.

Zone Refining

• Also called zone melting or floating zone process.
• Involves melting a narrow region of a crystal, moving this molten zone to purify the material by leaving behind purer solid as it advanced through the ingot.

Czochralski Pulling Technique

• Crystal growth method for producing monocrystalline semiconductors.
• Discovered by Jan Czochralski in 1916.

Grinding and Slicing

• Ingot Surface Grinding: Smooths the outer surface of the crystal to create uniform ingots.
• Ingot Slicing: Uses a diamond-edged blade to slice the ingot into thin wafers while maintaining handleability.

Wafer Cleaning and Polishing

• Wafer Scrubbing: Ensures constant flatness and thickness by grinding both sides.
• Wafer Rinsing: Chemical etching to remove surface contaminants.
• Wafer Final Polishing: Achieves a mirror-like finish on one side, indicating contaminant-free status.
• Resistivity Check and Inspection: Ensures material quality before further processing.

Assignment

• Research paper should cover:
  • History of Integrated Circuits.
  • Various package types available.
  • Example IC from any manufacturer and its applications.
  • Advantages of using the selected IC.