Driving Fab Performance Metrics from the Sub-Fab to the Cleanroom

By Alan Ifould This is the 10th post to this blog in a year where change has been an overriding theme.

By Alan Ifould

This is the 10th post to this blog in a year where change has been an overriding theme. In the previous posts we described how we use our Operational Excellence (OE) model to deliver value to our customers. Now I would like to review some of the key themes tying them together under the rubric of fab performance objectives – Safety, Quality, Delivery, Cost, People and Environment (SQDCPE), an essential model in the OE toolbox. A detailed explanation of SQDCPE for Semiconductor Manufacturing is available in this interactive e-book

A quick recap on Operational Excellence

We describe OE as a methodology to achieve the best possible outcomes and long-term profitability of our customers’ business. The approach is to create an environment where machines, people and processes reach their full potential. The focus builds on the principles of LEAN 6 sigma (6σ) manufacturing, but its emphasis is on creating a mindset and culture that ensures the long-term viability of the business. It has deep roots in business concepts developed in Japan (Shingo and Kaizen), but it seeks specifically to understand customer success and create collaborative feedback processes for continual improvement. 

Domain knowledge (people applying their expertise to data and technology to solve complex problems) and a culture of leadership are the main threads of the Operational Excellence model that provide long-term guidance to grow the organization. For the organization to succeed and prosper, every member must be empowered and motivated to see the flow of value and act to improve it.

The Shingo institute at the Jon M. Huntsman School of Business in Utah defines 10 core principles to guide leadership and domain knowledge: 

  1. Respect Every Individual – Every individual is worthy of respect, deserving of recognition, and able to contribute and improve.
  2. Lead with Humility – A leader’s willingness to seek input, listen carefully, and continuously learn creates an environment where associates feel respected and energized and give freely of their creative abilities.
  3. Seek Perfection – Perfection is an aspiration not likely to be achieved, but pursuing it creates a mindset and culture of continuous improvement.
  4. Embrace Scientific Thinking – Innovation and improvement are the consequence of repeated cycles of experimentation, direct observation, and learning. 
  5. Focus on Process – All outcomes are the consequence of a process. It is nearly impossible, even for good people, to consistently produce ideal results with a poor process. 
  6. Assure Quality at the Source – Perfect quality can only be achieved when every element of work is done right the first time. If an error occurs, it must be detected and corrected at the time and place it is created.
  7. Improve Flow & Pull – Value for customers is maximized when it is created in response to real demand in a continuous and uninterrupted flow. Avoid creating or having more products or services than are necessary to serve customer demand. Ensure that resources are available when and where they are required.
  8. Think Systemically – Understanding the relationships and interconnectedness within a system enables better decisions and improvements.
  9. Create Constancy of Purpose – Providing clear and unwavering direction about why the organization exists, where it is going, and how it will get there enables people to align their actions, and to innovate, adapt and take risks with greater confidence.
  10. Create Value for the Customer – Ultimately, value must be defined from the customer’s point of view: know what they want and are willing to pay for. Organizations that fail to deliver effectively and efficiently on this most fundamental outcome cannot be sustained over the long-term.

Source: https://shingo.org/shingo-model/

Through Operational Excellence, an organization can improve its company culture and performance and achieve long-term sustainable growth. An important question at this point is how this is guided by fab performance objectives to ensure the best results? 

Fab Performance Objectives – SQDCPE

SQDCPE is a tool used to support transparency within a working- or decision-making unit (DMU). It grew from the practice of posting key performance indicators (KPI) on a board in the work area for all to see. The boards arranged the KPIs in columns, each representing a category: safety, delivery, quality, people, cost, and the environment. Each column heading prominently displayed the first letter of the category name, thus begetting the rather awkward and unpronounceable acronym for the tool.

It is easy to get side-tracked by narrowly defined KPIs. They must be well chosen to have the desired effect. In keeping with the admonitions of the 8th and 10th principles of Shingo, “Think systematically” and “Create value for the customer”, we need to consider what success looks like for the customer. Otherwise, we might think we are successful, but the customer might have an entirely different view of the situation. For example, we often track pump and abatement uptime and MTBF (mean time between failure) as primary performance metrics. But we can easily achieve good numbers for these metrics and still have an unhappy customer. This is because they do not capture what the customer really cares about, things like wafer scrap, wafer yield, process tool uptime, mean-time-between-service, and number of unscheduled events, all of which can be heavily influenced by our performance. Our value proposition must focus on removing the risk and uncertainty in vacuum system operations that impact fab metrics.

Let us take a closer look at the SQDPCE performance metrics.

Safety – Common indicators of safety are time lost due to injuries (lost workday case rate or LWCR) and the total number of recordable safety incidents (total recordable case rate or TRCR). Examples of OE influence include creating a culture of safety throughout the organization, processes for incident reporting, closure of safety issues, implementation of work standards, and 6σ performance. In June 2020, Edwards achieved a world class LWCR performance, benchmarked against leading semiconductor manufacturers.

Quality – Yield improvement (increase in number of good wafers produced) is the most critical goal for all semiconductor operations. Even incremental increases in yield can significantly reduce the manufacturing cost per wafer and overall profitability. Using an OE approach to enable proactive management of the risks associated with unscheduled vacuum equipment faults that can potentially cause wafer scrap events is critical.

Delivery – Fab output is the number of good wafers completed in a certain period.  We must understand the impact vacuum and abatement have on process tool availability and throughput. A secondary but still important effect is the number of wafers scrapped due to unscheduled downtime. Here OE must focus on assessing the best strategy to service and manage the vacuum and abatement system to minimize risk and uncertainty for the cleanroom.

People – Managing vacuum systems requires many people with a wide range of skills and both theoretical and hands-on knowledge.  These skills range across physics and chemistry, materials science, electronics, mechanical engineering, control systems and more. The OE model provides several insightful measures that we use to track our efforts to develop our most important resource – our people. These include time to competency, training hours, certification levels and personnel retention. The ultimate goal is to help them combine domain knowledge with contextual information to truly understand why events happen and to then mitigate or eliminate root causes. 

Cost – Impact on wafer cost can be direct or indirect. Direct costs include consumables, spares, and labor used by the vacuum and abatement systems and also by the process tools they support. Indirect costs include the opportunity cost of production lost on a process tool. The indirect cost of lost production may far outweigh direct costs, especially if the down tool is a bottleneck tool that effectively meters flow through the entire process. OE seeks to eliminate the surprises that cause the indirect losses.

Environment – Environmental protection and sustainability is one of the fastest growing performance indicators for manufacturers across the whole semiconductor supply chain. Wafer fabs incur costs related to various environmental requirements. In some places these are external regulatory requirements: the fab cannot operate unless toxic or global warming gases are contained. But increasingly they relate to internal efforts to achieve corporate sustainability objectives, including energy efficiency programs, strategic renewable energy initiatives, reduction of greenhouse gas emissions, and established climate change countermeasures.  The shared aim of these measures is to ensure all resources and processes are used at maximum efficiency with minimal negative impact on our shared environment. This is driven by circular business models enabled by OE which consider any and all waste as a potential input back into the system.

Looking back now at previous posts, we can index them into the SQDPCE framework by their primary focus and see how sub-fab Operational Excellence is able to contribute to overall fab effectiveness. (you can explore previous article links to delve deeper into each topic). 

Safety (S)

#3 Managing and Influencing Sub-Fab Safety – Developing a Culture of Safety
The sub-fab is a more dangerous environment than the cleanroom. People interact closely with machines and potentially harmful materials. The management of safety impacts production and reputation. The solution requires a holistic OE approach to safety – involving people, processes, machines, and data. Read full article

Quality (Q)

#6 Data Sharing – The Cost of Inaction
Equipment selection and maintenance decisions in the sub-fab are increasingly impacting throughput. Data collection and analysis with a new service management app helps turn data into actionable insight. Read full article

Delivery & Cost (DC)

#1 Covid 19 – Challenges and the New Normal for Sub-Fab Support
We learned what works and what does not work to protect our people and our customers while maintaining business activity during the pandemic. We saw large scale adoption of tele-technologies and learned how to maintain the human interaction that is so critical in the value chain. Both the cleanroom and the sub-fab continue to embrace the wide-ranging use of data analytics and remote support.  Read full article

#2 Smart Manufacturing – Redefining the Semiconductor Sub-Fab
Smart manufacturing needs the essential subject matter expertise that generates actionable insights from data. Data analytics will help pinpoint root causes of faults more quickly, but domain knowledge is needed to get the best outcome.Read full article

#5 Cleanroom vs. Sub-Fab Vacuum – 5 Key Reasons to Align
Down events in the sub-fab cause production delays and wafer scrap. Without the sub-fab’s essential services and support, operations in the cleanroom come to a sudden and costly halt. We discuss how to align sub-fab and clean room to improve yields, reduce downtime, avoid scrapped wafers, decrease maintenance costs, and increase productivity and profitability. Read full article

#8 Shaping the Future – Innovations in Maintenance
How does maintenance in the sub-fab affect fab performance? What are characteristics of different approaches, and what are the challenges we face as we move from level to level in the service maturity hierarchy? Read full article

#9 Shaping the Future – Connecting the Creativity of Humans
Smart tool kits for maintenance empower faster and more effective decisions. New technologies can enable the full value of human creativity, but they must be steered by an out-come based business model. Revenue and cost saving opportunities are growing. Read full article

People (P)

#7 People and Skills in the Sub-Fab and Cleanroom
Human creativity must be the driving force to realize the benefits of Industrie 4.0. Human skills and knowledge remain essential throughout the sub-fab and cleanroom. The three Cs: competence, confidence, and commitment. Read full article

Environment (E)

#4 Circular Economy – 3 Ways to Drive Business Value
Applying circular economy principles for sustainable manufacturing processes: we offer 3 examples of the circular economy – designing out waste, prolonging useful life, and remanufacturing existing systems. Read full article

Summary 

In our previous posts, we have described various aspects of our efforts to deliver value to our customers under the umbrella of Operational Excellence. Here, in keeping with the OE directive to “Think systematically,” we have tried to organize those posts under the rubric of SQDPCE, an essential tool for promoting transparency (“Create constancy of purpose”). We hope we have given the reader some insight into how Edwards works every day to “Create value for the customer”. To review and share the topics discussed in this post an interactive e-book “Achieving Fab Performance Metrics from the SubFab to the Cleanroom” is available to download from the Edwards Innovation Hub.   

In future posts we will shift our focus to sustainability and minimizing the impacts of semiconductor manufacturing on the environment.

Acknowledgements – I want to thank my colleague Matt McDonald for his valuable insights and contributions to this discussion, and to thank again the many other contributors who have supported me through this blog series.

Website: edwardsinnovation.com

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