ECE6450L11-Etching especially Plasma Etching

ECE6450L11-Etching especially Plasma Etching - Lecture 11...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 6450 - Dr. Alan Doolittle Georgia Tech Lecture 11 Etching Techniques Reading: Chapter 11
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 6450 - Dr. Alan Doolittle Georgia Tech Characterized by: 1.) Etch rate (A/minute) 2.) Selectivity: S=etch rate material 1 / etch rate material 2 is said to have a selectivity of “S” for material 1 over material 2. Rate Etch Vertical Rate Etch Lateral 1 = A 3.) Anisotropy: 4.) Under cut: If 0.8 um lines result from an etch using 1 um photoresist lines as a mask, it is said that the process bias is 0.1 um for that particular etch. Etching Techniques
Background image of page 2
ECE 6450 - Dr. Alan Doolittle Georgia Tech General Increasing Anisotropy* * Some wet and plasma chemistries can have high anisotropy by using the chemistry to etch preferred crystalline planes. Increasing Mean Free Path Anisotropy can depend on mean free path, or on DC plasma bias. Increasing mean free path (generally) increases anisotropy Increasing DC bias (generally) increases anisotropy Controlling Anisotropy
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 6450 - Dr. Alan Doolittle Georgia Tech Etching can be characterized by how much of the process is: Chemical: Using the chemistry of the etch to remove material into a solution (liquid or gaseous solution) Sputtering: In plasma systems, Ions can be accelerated fast enough so as to “Ram” into the surface, “knocking out” atoms/molecules Many etching techniques use both chemical and sputtering. 1.) Wet Chemical Etching: Advantages: Cheap, almost no damage due to purely chemical nature, highly selective Disadvantages: poor anisotropy, poor process control (temperature sensitivity), poor particle control, high chemical disposal costs, difficult to use with small features (bubbles, etc. ..). Advantages Common to all of the following: Low chemical disposal, temperature insensitivity, near instant start/stop (no drips, etc. .), applicable to small features (gas permeation of small features). 2.) Plasma Etching: Advantages: Moderately anisotropic using sidewall polymerization techniques (discussed later) , can be selective Disadvantages: Ion damage, residue 3.) Reactive Ion Etching: Advantages: Highly anisotropic using sidewall polymerization techniques, can be selective but less so than plasma etching due higher DC bias and longer mean free path.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 12

ECE6450L11-Etching especially Plasma Etching - Lecture 11...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online