How to Record Wafer Yield Variance (The 'Good Die' Adjustment)
Adjusting the value of inventory when a wafer produces fewer working chips (Die) than the theoretical maximum.
| Account Name | Type | Debit ($) | Credit ($) |
|---|---|---|---|
| Manufacturing Variance - Yield Loss | Expense (+) | 15,000.00 | - |
| Inventory - Work-in-Process (WIP) | Asset (-) | - | 15,000.00 |
💡 Accountant's Note
In semiconductors, 'Yield' is everything. If a wafer has 1,000 potential chips (dies) but a laser-test proves only 700 work, the 'Yield' is 70%. The cost of the 300 failed chips cannot be capitalized into the good ones indefinitely; the excess cost resulting from 'abnormal' yield loss must be expensed as a variance in the period it occurs.
Practitioner & Systems Framework
💻 ERP Architecture
Integration with a Manufacturing Execution System (MES) like Applied Materials or Camstar is vital. The 'Sort/Probe' test triggers the update from 'Gross Die' to 'Net Good Die' in the inventory sub-ledger.
⚠️ Audit Flags
Consistent Yield Fluctuations. High yield loss in a new production 'Node' (e.g., transitioning to 2nm) is common, but if it remains high, auditors will require an impairment of the entire WIP pool.
📄 Required Documentation
Wafer Sort Report (Probe Test), Production Lot Summary, and the Yield Target vs. Actual analysis.
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Expert Analysis by Qusai Ahmad
General Accountant Supervisor & IFRS Specialist
Specialized in SAP GUI automation and Middle Eastern tax compliance. Building digital tools for the next generation of finance leaders.
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