Pacific Semiconductors, Inc. (PACSEM) came into being in February 1988, being the newest addition to the booming Philippine electronic industry. The company is primarily involved in contractual assembly work for the semiconductor industry. It is housed in a 70,000 square foot assembly house in Taguig, Metro Manila.

The facility boasts of the latest in equipment technology and facility to satisfy the myriad demand of the industry. PACSEM manufactures microchips such as PDIPs, CERDIPs, Flat Packs, and Metal Cans processed through an assembly house located in its plant in Metro Manila. PACSEM boasts of being a full SPC assembly house which makes quality its “first priority”.

Case Introduction:

Each microchip produced by PACSEM goes through a specific process flow appropriate for the type of device. At the final stage of the production process, microchips go through a marking and curing process known as electrophoresis (MCE) which may create variations that may affect the surface quality of the microchips produced due to increase and decrease in UV exposure. To ensure quality, the marking and curing process undergoes rigid statistical process control. The following table contains the curing time (in minutes) during one of its production run. The objective is to achieve statistical control of the cure times using X̅- and R-charts. Based on the table below:

Sample number	1	2	3	4	5	6	Mean	Range
1	.481	.494	.493	.511	.486	.499
2	.529	.509	.516	.494	.499	.506
3	.521	.504	.515	.488	.496	.500
4	.489	.492	.483	.487	.495	.506
5	.481	.490	.526	.469	.472	.502
6	.506	.495	.507	.493	.473	.495
7	.504	.494	.490	.471	.495	.512
8	.485	.497	.498	.474	.525	.501
9	.516	.507	.517	.506	.497	.501
10	.497	.505	.516	.511	.495	.505
11	.492	.486	.468	.492	.495	.482
12	.522	.499	.526	.506	.483	.459
13	.510	.512	.493	.525	.521	.512
14	.500	.503	.507	.501	.487	.521
15	.513	.506	.499	.511	.493	.516
16	.523	.492	.479	.480	.473	.506
17	.496	.491	.513	.484	.477	.485
18	.475	.492	.493	.485	.515	.493
19	.491	.504	.486	.497	.511	.536
20	.512	.497	.470	.504	.509	.490

Part I

1. Develop X̅- and R-charts using these data with the method described in your textbook. (show your work)
2. Plot the data on the chart and analyze the process flow. (show your work)
3. Does PACSEM achieve its objective on quality?
Part II

The following data is in the succeeding production run. Using the X?- and R-charts

you developed above, plot these data on the chart and give your comments.

Is the process in or out of control? If it is out of control, why, please identify which sample or samples are out of control.

Sample Number	1	2	3	4	5
21	0.481	0.486	0.493	0.499	0.511
22	0.529	0.499	0.516	0.506	0.494
23	0.544	0.529	0.515	0.53	0.533
24	0.489	0.495	0.483	0.506	0.487
25	0.422	0.472	0.526	0.434	0.469
26	0.506	0.473	0.507	0.495	0.493
27	0.504	0.495	0.49	0.512	0.471
28	0.485	0.525	0.498	0.501	0.474
29	0.516	0.547	0.517	0.555	0.506
30	0.497	0.495	0.516	0.505	0.511

Part III

Based on the production run above, quality control personnel reported defects

(indicated in the chart below) during their 100% inspection of the units.

Sample Number	1	2	3	4	5	6	7	8	9	10	11	12
Sample	100	100	100	100	100	100	100	100	100	100	100	100
	7	9	7	7	7	9	7	10	8	11	10	8




Develop a p-chart and a c-chart using these data and plot the data on the chart at a 95% confidence interval.

2. Give your comments regarding the process. Are the defects? Why or why not?

Answer rating: 100% (QA)

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