3 Step Verification

Three step verification approach

One of the main features supported by the XperiDesk Suite is the process design for manufacturing (DFM). To verify a process design, process DFM can be considered a three step approach using:

  • Process flow consistency assessment
  • Process flow simulation and calculation
  • Experimental verification

The XperiDesk Suite has been designed to enable this three step verification approach. The three steps are decribed in more detail in the following blocks.

Flow Chart Costs

Verification of Manufacturability

The first and least expensive step in the verification of high-tech manufacturing processes is a formal verification based on the process flow model: the consistency check. In this phase the process flow is checked using rules applied to the process steps of the flow. These rules consist of abstract process knowledge stored in the system by the process engineers. Each rule can demand or recommend the compliance with certain criteria while a single criterion can be the pre or post-processing of the process step. Additionally it is possible to forbid (NOT operation) or recommend against the usage of certain steps or parameter values.

Some rules are only valid if certain conditions are met. Conditions could be the usage of certain process steps or groups or the matching of certain parameter values. They can be used to activate or deactivate rules. Finally it is possible that a process step must comply with more than one rule or that only one of a set of rules must be met.

The XperiCipe system offers in this phase an easy to use interface to manage these rules. Completed process flows can be checked using the XperiFication system and the results are shown in understandable clear graphical output. If conflicts are detected, the conflicting steps are highlighted to provide the information where changes are necessary.

These functionalities are realized in the module XperiFication. Read more about this module »

 

Verification by Simulation

The verification of manufacturability only indicates the feasibility of the process flow and does not assess the physical results of the processing. To ensure that a process flow leads to the desired results, it is necessary to verify the flow either by simulation or experiment. Though experimental verification gives the most reliable results, it is also very expensive and time-consuming. Especially in early design stages, when the process designer still experiments with different process steps, parameters, and lithography masks, a fast feedback is of higher importance than physically exact results. During these stages, process simulation is the most appropriate method for verification as it is comparatively fast and inexpensive.

In this phase the XperiCipe system helps the designer by providing means to manage simulation models in an intelligent way. Interfaces to existing simulation tools are provided by the XperiSim system. This allows to use the available simulation tools to their full potential. Even non-experts can now gain the benefits of the simulation approach.

These functionalities are realized in the module XperiSim. Read more about this module »

 

Verification by Experiment

After the first two rule- and model-based verifications, the experimental verification proofs the manufacturability in a real fabrication line. Because this step implies the production of real prototypes, the verification by experiment is the most expensive one. This is due to the involved production costs themselves, as well as the time costs these experiments require. For thin film technologies the flow of the experimental verifications involves typically at least the following steps:

  1. Setting up an experiment plan, potentially supported by a Design Of Experiment (DOE) system.
  2. Defining different lots, their purposes, analysis and tests to apply, and the amount of wafers per lot.
  3. Processing of lots and their wafers where different wafers might receive slightly modified processing.
  4. Performing of different analysis during the processing sequence.
  5. Analysing and testing the wafers/devices.
  6. Performing failure analysis of the wafers and devices.
  7. Comparing experimental results with design expectations.

This list shows that there are relations between experiments, lots, wafers, process steps, and
process flows (all referred to as development dimensions) regarding the different assessments
and their results. The XperiLink system offers a way to manage all these data entities and relate
them to each other. It eases the search and reporting tasks and allows to keep track of all running
as well as finished lots, wafer, process, etc.

These functionalities are realized in the module XperiLink. Read more about this module »