The SEMATECH Cost of Ownership Model

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The SEMATECH Cost of Ownership Model

• Mike Berman
• U of Arizona

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AGENDA

• Why use it?
• How to use it?
• What if?
• CoO of a new system
• Process 1 Vs Process 2
• Quality Improvement Tool
• Summary

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Purpose

• The SEMATECH Cost of Ownership (SCoO) model was
  developed to address the economic and productive
  performance of a tool while operating in
  pre-production or in production.

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Description

• The SCoO model is a calculator to perform a cost
  comparison of options for completing a step in a
  semiconductor wafer fabrication process

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Why is the SCoO so important?

• Manufacturing cost control is critical to
  survival in the market place.
• For cost control you must
  
• Know the cost of each step
• Understand the reasons for these costs
• Control and reduce the costs
• ASPs drop each year, So must costs!!!

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Why use the SEMATECH Model?

• Independent of OEM the Supplier
• Developed by SEMATECH
• It is the De Facto standard
• It permits Apples to Apples comparisons

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Cost of Ownership Calculation
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The SEMATECH Model is NOT

• A MEASURE OF THE PROCESS
• If the new process does not work or
• Has a lower yield, do not waste your time
• ABSOLUTE
• Able to make tools smaller!

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Model Description

• The Model is very comprehensive
• Up to 90 inputs 210 output parameters
• Can be used with as few as 10 inputs 1 output
• Once understood it produces simple and fast
  results
• The Rewards are enormous
• High benefit to effort ratio
• Detailed insight into the cost makeup of each
  step
• What if type questions can be addressed
• The SCoO is most useful as a comparison tool.

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Dos Do Nots

• Do not improve the technique used to find the
  values
• Do add spreadsheets within the spreadsheet
• See next page for examples

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Examples

• For sputter Target cost per wafer
• Target Life, Target cost, Avg. process dep
• Cost of gas per wafer(Etch/CVD)
• Volume cost of tank
• Usage, flow and time (all steps)
• Cmp
• Pad cost, life(in polish mins or wafers)

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Major parts of the Model

• Title Fill in more detail than you will need!
• In 1 year they will all look the same!
• VOLUME/THROUGHPUT DATA
• EQUIPMENT DATA
• PRODUCTION/RUNNING DATA (usage)
• MAINTENANCE COSTS
• PERSONNEL PER SYSTEM /STANDARD RATES
• ANNUAL COST PER GOOD WAFER ()
• MANAGEMENT SUMMARY
• PHOTO LITHOGRAPHY WORK SHEET

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E10-90 Equipment States Stacking Chart
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Title Fill in more detail than you will need!
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VOLUME/THROUGHPUT DATA
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EQUIPMENT DATA
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PRODUCTION/RUNNING DATA (usage)
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MAINTENANCE COSTS
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PERSONNEL PER SYSTEM /STANDARD RATES
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The Must have lines (only 7)
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The more you use, the better it is!
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How to use the SCoO

• Its in Excel-not PowerPoint!

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Standard Rates

• Burdened Salary
• Engineer 115,000
• Supervision 100,000
• Operator 30./Hr
• Maintenance 35./Hr
• Administrative Rates
• Insurance 0.47
• Personal Prop. Tax 1.34
• Interest 10.0
• Inflation Rate 3.0
• Life of Equipment 5 years
• Test Wafer Cost 80.00
• Value of incoming 100 to 1400
• Value of completed 1,500.

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Output (line 525)
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Output (line 357/382)
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SURPRISES !!

• Capital cost of the equipment may not be the
  driver for Cost of Ownership
• MTBF (gt75 hr.) impact on utilization cost
  reduction is not as significant as previously
  thought
• Defect density Line Yield are far more
  important then previously anticipated
• The cost of the wafer at the process step is more
  important than previously considered

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Defect Density

• Die area (Line 104) 1 cm2
• Probability of a failure (Line 105) 16.6
• Defect Density (Line 21) Vs Cost of Wafer
• .01 (defects/cm2) 8.49
• .05 15.06
• .10 23.27
• .2 39.69
• .5 88.95
• .9 154.64

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CoO Scrap () Calculation
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CoO of a New System

• Use your best numbers
• Be fair
• Use a run rate of Max. (for most models)
• This is NOT a measure of the Process
• This is only an estimate, your real cost may vary

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Process 1 Vs Process 2

• Be Fair
• Throughput Defect Density are the main Drivers.
  
• Use real numbers, not specs
• If you do not have Real Defect Density Data,
  use 0.

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Quality Improvement Tool

• Major use of the Model
• Only change key cells
• Changes in Throughput need changes in
  Production requirements
• This can be used for small changes

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How do I get my copy?

• SEMATECH stopped support on 4-15-95.
• Now it is call TWO COOL from Wright,
  Williams, Kelly
• 11875 Dublin Boulevard, Suite D262
• Dublin, CA 94568
• 1-510-803-5880
• Cost 7,190.00 (in 1995)

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SUMMARY

• You now know more than most users
• Use it, work with it
• Split your screen, place line 382 at the top of
  your screen, and make changes and see how they
  change the total CoO.