Equipment operators, production managers, and process engineers are all too familiar with the challenges that accompany a well-executed product flow. While the manufacturing execution system (MES) handles many aspects of product flow execution and is critical in many factories, recipe management capabilities like recipe body management and version tracking or recipe download and selection at the equipment level may not be available. Without these capabilities, recipe management becomes a complex task for shop floor personnel to contend with. For this reason, manufacturers tend to seek out automated recipe management solutions for their efficiency, accuracy, and ability to improve process controls. This is especially true for semiconductor fabs where recipe integrity and confidentiality are of paramount importance and recipe data must be captured for traceability to meet quality compliance requirements.
What is Recipe Management?
Before going much further, let’s briefly identify and define some terminology and logistics related to recipe management for the purposes of this discussion. When a production order is executed for a particular product, that product is manufactured based on a series of process steps, or a “product flow”. Each process step within the product flow is assigned to a specific machine and is associated with an instruction set, or “recipe”, detailing equipment-specific settings of its processing program for the product. To begin a process step, the product is identified for processing and the equipment is set up according to recipe specifications for that equipment and product (such as temperature, pressure, processing time, etc.). The product is then placed at the equipment, processed, and queued to the next process step.
Recipe management systems make the work of equipment operators, production managers, and process engineers easier, more efficient, and less error-prone by:
Automated recipe selection
Reduced equipment set-up requirements
Centralized storage and management of recipe bodies
Simplified recipe maintenance
Automated and digitized quality management efforts
Recipe management systems automate the recipe selection process, thereby eliminating the possibility of misprocessing related to recipe selection.
Recipe management systems are capable of determining the correct recipe to process material based on:
- equipment type
- processing context
- equipment capability
Advanced recipe management solutions may integrate equipment capability data along with processing rules to ensure that, even equipment with reduced capabilities, operates at maximum capacity. For example, consider a multi-chamber tool where one chamber isn’t functioning or has limited functionality. Rather than rendering the entire piece of equipment unusable, recipe adjustments can be made to maximize the utilization of the remaining viable chambers as well as any chambers with limited functionality.
Increase Yield and Quality
Recipe management systems can leverage information from advanced process control (APC) systems to enhance capabilities for real-time, automated process adjustments based on the outcome of a product at a particular stage in order to improve product quality and increase yield.
Increase Equipment Utilization and Throughput
Recipe management systems use rules to determine the best fitting recipe under given circumstances. An example is to avoid intermediate equipment conditioning steps using recipe groups that share similar processing requirements in order. When paired with event-driven dispatching systems, manufacturers achieve the greatest rewards in terms of reduced equipment setup times, maximized equipment utilization, and increased throughput.
Improve Quality Management Efforts
Quality management efforts exist to ensure that any recipe used in production has been appropriately tested, reviewed, and approved. Conducted manually, these efforts can be time-consuming and tedious. Recipe management systems automate and digitize efforts around recipe versioning and documentation of recipe review and approval processes.
Simplify Recipe Maintenance
Recipe maintenance is simplified with a recipe management system through parameterization and centralized recipe storage.
Product variations are abundant in manufacturing and often result in the creation of multiple recipes to produce variations of a single product. An alternative approach, using a recipe management system, involves reducing the overall number of recipes to a small number of baseline product recipes with parameters that allow values to be passed in to achieve the desired recipe variation for a given product. The benefit? There is only one recipe to maintain for a given product, so recipe modifications are easy.
Centralized Recipe Storage
Centralized recipe storage provides production equipment global access to recipes. A familiar scenario on the production floor may be the effort required to modify and/or maintain recipes when more than one piece of equipment accesses locally stored recipes. In that scenario, recipe maintenance is handled one-by-one, at each piece of equipment. Global accessibility eliminates the tedious task of local recipe maintenance.
Ultimately the features and functionalities of an automated RMS range from basic to highly sophisticated and are customizable based on the manufacturer’s requirements. In addition to automating recipe selection, RMSs function to accomplish the following:
- control and document recipe modifications
- maintain recipe states and versions
- manage user permissions
Recipe State and Version Controls
Recipe management complexities increase as the recipes themselves increase in complexity and/or when recipe modifications occur. For instance, in the execution of a product flow, certain process steps will call for some quality evaluation. Based on the results of the evaluation, recipe adjustments may be required. Automated recipe management ensures that once the recipe adjustments have been made and approved, the approved recipe version becomes “active”. The active recipe, commonly referred to as the “golden recipe”, is then used for all subsequent product flows at this process step.
Conversely, it may be determined that a particular recipe version produces a high amount of scrap and should not be used anymore. When integrated with shop floor equipment and an MES, an automated recipe management system (RMS) provides certainty that only the correct recipe will be used on a specific piece of equipment for the material being processed. Though these are some very basic examples, it is possible to see the value in automating the handling of recipe versioning and validations.
User Permission Management
Establishing user permissions is an important aspect of recipe management. User groups can be created with permissions to add, modify, and define golden recipes while other users may only have permission to view recipes and only select from approved or golden recipes. Establishing user permissions will prevent unintentional and unauthorized modifications recipe changes and provide a level of control to ensure that only golden recipes are selected.
Automated recipe management systems enable advanced features and functionality which are dependent upon existing automation infrastructure. At a minimum, your production environment should have the following systems in place before implementing an RMS with all of the features and functionality described above:
If the requirements of your factory don’t involve this level of complexity, a less sophisticated, scaled-down RMS solution can be implemented to provide recipe selection, version management, and other features as needed and supported by the existing software and hardware on the shop floor. As with all digital transformation efforts, it’s important to first carefully consider the short and long-term requirements for your production environment, then select the most fitting solution.
SYSTEMA provides customized recipe management solutions for the semiconductor industry which are tightly integrated with SYSTEMA’s Equipment Integration & Automation Suite (EI Suite). For more than 25 years, SYSTEMA has developed and implemented solutions designed around the unique requirements of semiconductor manufacturers.