The Winding Road to Automation


Automation is touted as the “magic bullet” to preventing contamination problems. We often assume that automation improves the process by removing the people. We know that humans generate contamination, both particulate and thin-film. While removing the people may eliminate one contamination source and one source of variability, there is far more to automation than, well, automating. You may have removed the human factor from the operation, but notfrom the process design.

Automation typically requires a substantial investment in capital equipment and facilities modification. Therefore, automated critical cleaning is reserved for true, value-added applications, such as removal of process chemicals or achieving the desired surface characteristics. Because the automation process is designed by people, investing plenty of up-front time can result in a more effective automated assembly.

UNDERSTAND THE PROCESS
Automation brings consistency. Too often, processes are automated without fully grasping the nuances of the process in question and of the overall production environment. When this happens, the automated process may be consistent,but it can be consistently incorrect.

Process understanding has been divided into eight stages of knowledge.1 In Stage 1, we know the product works, but have no idea of how to achieve the desired output. In Stages 2 through 5, we begin to recognize major variables, grasp the relevance of variables, engage in metrics, and then begin to exert local control over the variables. In Stages 6 and 7, we understand how the variables impact the output. Stage 8 is complete knowledge; a lofty goal rather than a status achieved by mere mortals. Table 1 describes the relationship of these stages to cleaning and contamination control processes.

Stage

Stage of Knowledge

Comments

1

Complete ignorance

Can be a pathway to innovation

2

Awareness of parameters,
ignorance of relative importance

Assembly as art, process steps
kept secret, not written

3

Understand parameters, can’t control them

Environmental or customer mandates
can restrict options & advancement

4

Control of mean, uncontrolled parameters

Beginning of process control

5

Process capability

• Cleaning recipes
• May reveal over-cleaning,
over-purification of chemicals
• Cost savings

6

Process characterization

• Understanding “how” process works
• Fine-tune, optimize output
• Reduce costs
• Must reach this stage for successful
automation

7

Understanding “why” the process works

Rarely achieved in surface
preparation

8

Complete process understanding

A goal to approach

Table 1. Automation journey applied to surface cleaning and contamination control

OBSERVE THE PEOPLE
In our experience, the shortest route from Stage 1 to Stage 5 is to work directly with the technicians. In eliminating the human operator without good understanding of the cleaning process, primary sources of knowledge may be inadvertently ignored. Even if technicians follow every step of supposedly well-documented fabrication and cleaning processes, the first step in automation should be to determine what the process steps actually are, not how steps are written in the work instructions. Understanding people involves observing and questioningin a retribution-free environment.

Related Topics: Contamination Control In and Out of the Cleanroom April 2007 Contamination Control