SEMI E168 – Specification for Product Time Measurement

Introduction to the SEMI E168 Standard Suite

SEMI E168 — the Specification for Product Time Measurement (PTM) — is the semiconductor industry’s authoritative standard for tracking how time is spent on every product unit moving through a factory. The suite of PTM standards E168 gives semiconductor manufacturers and equipment suppliers a rigorous, vendor-neutral framework for measuring and categorizing product time across the entire factory life cycle.

• Originally developed from the Sematech “Wait Time Waste” initiative
• Does for product material what OEE (Overall Equipment Effectiveness – SEMI E10) does for equipment; in other words, accounts for every minute of a product unit’s time in the factory and allocates it to a unique category
• Uses existing events defined in GEM300 standards to categorize time usage
• Product units can be entire lots (factory level) or individual substrates (equipment and factory level)
• Concepts directly apply to wafer fab process equipment, automated material handling systems (AMHS), and material control systems (MCS)
• Detailed visibility afforded by the PTM standards provides an objective basis for significant throughput and productivity improvements
• Central to modern smart manufacturing and Industry 4.0 strategic principles

Purpose of the SEMI E168 Standard

The core mission of SEMI E168 is to eliminate product time waste. The standard provides a common, unambiguous methodology for identifying exactly where time is lost as a product unit travels through the factory — producing results that are comparable across manufacturing processes, equipment suppliers, and production lines. Moreover, applying this standard in real time enables manufacturers to identify changes in throughput that may occur during production for a variety of reasons, catching so-called “productivity excursions” before they cause serious losses in capacity. This is especially relevant for “bottleneck” equipment (e.g., lithography), because lost production for these processes can never be recovered.

• Replaces proprietary, ad hoc measurement approaches with a uniform methodology
• Structures factory and equipment data for systematic waste detection
• Enables both systematic and situational reduction of waste in the product life cycle

Delivers measurable business outcomes: shorter cycle times, higher throughput, and more efficient

Key Concepts and Features of SEMI E168

SEMI E168 defines a Product Time Measurement (PTM) methodology built around three foundational concepts:

Complete Time Accounting

• Breaks the entire timespan of a product unit’s life in the factory into contiguous, non-overlapping segments – no minute goes unexamined
• This is the “dual” (orthogonal view) of productivity that has traditionally been applied to the equipment

Granular “Time Elements”

• Explicit time elements tied to specific sets of factory events (start, stop) and associated context data
• Leverages GEM/GEM300 begin/end triggering events for precise measurement
• Produces a structured, analysis-ready dataset for downstream analysis

Active vs. Wait Time Classification of Time Elements

• Active time — product is being processed, moved, or otherwise acted upon
• Wait time — product is idle, queued, or waiting on equipment, an equipment component, some external system, logistics, or (in rare cases) personnel

Additional Design Characteristics

• Companion standards extend the concepts and analysis framework defined in the primary standard further:
  • 300mm production equipment
  • Material Control Systems (MCS)
  • Automated Material Handling Systems (AMHS)

• These specifications map standard events from each of the equipment/system categories above into specific active and wait time elements for subsequent analysis by their respective domain experts.

Why SEMI E168 Is Important to the Industry

In an industry where a single fab represents billions of dollars in capital investment, even seemingly minor throughput gains translate directly to additional revenue, return on invested capital (ROIC), and overall competitive advantage.

For Chipmakers (foundries and IDMs)

Collecting the events prescribed by the PTM standards to generate the set of active and wait time elements that result

• Provides structured data to reduce cycle time and improve on-time delivery
• Enables evidence-based capacity decisions. Industry experts estimate complex multi-chamber equipment may hold 5–7% untapped capacity — invisible without a standardized measurement framework like E168.

For Equipment Suppliers

PTM standards compliance

• Gives customers the visibility needed to optimize tool utilization
• Accelerates fab acceptance and qualification
• Signals a serious commitment to smart manufacturing

For Software and Automation Suppliers

The PTM standards establish the semantic and data model framework for high-value analytics applications, such as

• Fault detection and classification (FDC)
• Advanced process control (APC)
• Throughput optimization
• AI/ML-driven factory intelligence and ensure that the related analytics are built on a reliable, standards-aligned data foundation.

Cross-Industry Benefit

• Enables apples-to-apples benchmarking of production line performance across facilities, suppliers, and regions
• Eliminates the need for expensive custom integration work previously required for cross-site comparison

PDF Solutions Products that Support SEMI E168

PDF Solutions offers a comprehensive portfolio of equipment connectivity and smart factory software solutions that provide the foundational data infrastructure needed for SEMI E168 implementation.

• Cimetrix® CIM300 — GEM300 Software Development Kit: implements the SEMI GEM300 standards referenced in the time element definition tables: E40 (Process Job Management), E87 (Carrier Management), E90 (Substrate Tracking), E94 (Control Job Management), and E157 (Module Process Tracking). Generates the triggering events and state machine data on which E168 time element calculations directly depend
• Cimetrix® CIMConnect — SECS/GEM Connectivity: Enables equipment to communicate the event and status data that feeds PTM analysis. Enables Robust, production-proven connectivity for semiconductor manufacturing environments
• Cimetrix® CIMPortal Plus — Equipment Data Acquisition (EDA/Interface A): Delivers high-speed EDA capabilities compliant with E164 metadata standards and Supports real-time data collection plans (DCPs) to capture the complete set of E168 time elements at production speed and scale

All three products are deployed and proven in 300mm fabs worldwide, giving equipment suppliers and chipmakers the connectivity, data quality, and standards compliance needed to unlock the full productivity potential that SEMI E168 makes visible.