Example of Process Screening

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Predictive and Specialized Modeling • Process Screening • Example of Process Screening

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Example of Process Screening

The Semiconductor Capability.jmp sample data table contains 128 columns of process measurements. Each column contains 1,455 measurements. You are interested in identifying unstable processes. Also, each column contains a Spec Limits column property. If a process is stable, it is appropriate to calculate its process capability. You proceed to assess both stability and capability for this data table.

1.

Select Help > Sample Data Library and open Semiconductor Capability.jmp.

2.

Select Analyze > Screening > Process Screening.

3.

Select the Processes column group and click Process Variables.

Notice that the Control Chart Type is set to Indiv and MR.

4.

Figure 18.2 Partial View of Initial Report

The Process Screening window appears, showing a table of results for each process. The table is sorted by Stability Ratio. This is a measure of the stability of a process, where a stable process has a stability ratio near 1. Higher values of the stability ratio indicate a less stable process. (The sorting is indicated by the caret beside Stability Ratio in the report.) You want to take a closer look at processes with a stability ratio greater than 1.05.

5.

In the report window, select processes PMS1 through NPN9.

Each of these first 10 processes has a value of 1.05 or larger in the Stability Ratio column.

6.

Right-click the selected processes and select Quick Graph for Selected Items.

Figure 18.3 Quick Graphs for Highest Alarm Rate Processes

You decide to take a closer look at IVP8 (row 3, column 1 in the Graphs of Selected Items).

7.

Select the second process in the Summary table, which corresponds to IVP8.

8.

Right-click the selected process and select Control Charts for Selected Items.

Figure 18.4 Control Chart Builder Report for IVP8

A Control Chart Builder report appears. Because IVP8 has a Spec Limits column property, the report also includes a capability analysis.

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Help created on 7/12/2018