SEMI E157: Specification for Module and Substrate Process Tracking

Introduction to the SEMI E157 Standard

SEMI E157, titled as Specification for Module and Substrate Process Tracking, is the industry standard for communicating the progression of recipe-step execution to the factory host. Equipment reports when recipe steps start, complete, or fail — on process modules, and on substrates when the tool has no process chamber.

Purpose of SEMI E157

SEMI E157 defines a common way for production equipment to communicate recipe-step execution to factory automation systems — when a step starts, completes, or fails — together with context such as the process job, the recipe, and the affected substrates. Module process tracking reports recipe-step execution in a process module. Substrate process tracking is for equipment that does not have a process chamber and still needs to report recipe-step execution at the substrate level.

E157 standardizes:

• Module and substrate process tracking for recipe-step execution.
• Recipe steps, which are defined by the equipment.
• Each step has a step ID, so execution can be reported with a unique id.
• If a step fails, it can be repeated; Step Count records how many steps have been executed.
• Execution is reported for process modules, and for substrates when the equipment has no process chamber.
• By reporting a collection event at the start and end of each process step, users can configure targeted data collection for specific process activities, reducing unnecessary data capture and storage.

The result is that a factory system can collect recipe-step execution reports from every equipment in the production floor that implements E157.

Key Concepts and Features

Module Process State Model

The state model is intentionally lean with four states and seven state transition events making it straightforward to implement independently per process chamber. It tracks what each process chamber is doing at any given moment whether it’s idle or actively running a recipe. The core state models are:

• Not Executing
• Executing
• General Execution
• Step Active

As a recipe executes, the equipment reports state transitions together with key contextual information, including the active recipe and recipe component, the current recipe step definition, the equipment module where processing is occurring, the associated substrate(s) and process job(s), any recipe parameter settings applied for that execution, a running step count indicating the sequence of executed steps, a substrate process tracking identifier, and the current processing location or process area. Together, this information provides traceability of what recipe is running, where processing is taking place, what material is being processed, and the progression of execution through the recipe.

Substrate Process Tracking State Model

Substrate process tracking reports recipe-step execution for a substrate. It is used when the equipment has no process chamber but still needs to report which recipe step is running. The host follows each substrate with its own tracking instance. The Substrate Process Tracking State Model is how E157 reports recipe execution for a substrate (or a batch of substrates), instead of for a process chamber. The host sees whether that substrate is idle or running a recipe, and — if the equipment defines steps — which step is active. It is especially useful when there is no distinct process module (for example a conveyor or process area where wafers enter and leave independently). Each substrate that can run a recipe gets its own instance of the model, so staggered processing can be reported one substrate at a time. Equipment may implement this model, the Module Process State Model, or both. An equipment can implement both state models for the same substrate activities.

Conditional Data Tracing with GEM and EDA

With E157, factories can enable or disable GEM and EDA (Interface A) high-speed process data collection during the critical recipe steps using conditional trace requests which are designed specifically to take advantage of the SEMI E157 collection events and data. This keeps data volumes manageable. This approach:

• Reduces overall data volume.
• Maximizes the relevance of collected data
• Focuses analytical resources that matter most

Importance of SEMI E157 standard to the industry

E157 standard provides deeper visibility into what happens inside manufacturing equipment process modules and the substrates during material processing.

1. Consistent recipe and recipe-step reporting

E157 defines standard events for the start and end of recipe execution, with granularity down to the recipe step. The same events and data parameters apply across suppliers, so a host can interpret step execution the same way on every tool that implements the standard.

2. Context for process data

E157 events carry context such as the recipe, recipe component, step ID, step count, process job, and affected substrates. That context is what lets a factory link sampled trace data and summary process data to the exact part of the recipe that produced it.

3. Dual Interface Compatibility

E157 is designed to work across both major factory communication architectures:

• SECS/GEM (SEMI E5 and E30) — traditional equipment communication.
• Equipment Data Acquisition (EDA) / Interface A (SEMI E125 and E134) — high-speed data collection

4. Required by SEMI E164 for EDA

SEMI E164 calls for the inclusion of E157 and other GEM300 standards in the EDA equipment metadata model, so any E164-compliant equipment automatically includes E157 module process tracking as part of its interface. In other word, E164 defines the required EDA metadata representation for equipment that implements E157.

Products for SEMI E157 Compliance

PDF Solutions offers a comprehensive product suite purpose-built for SEMI E157 compliance, helping equipment suppliers implement the standard faster and with less risk.