Establishing a Baseline for Measuring Defects Introduced by Process-critical Components through SEMI SCIS Special Interest Group

By Paul Trio, SEMI

The Semiconductor Components, Instruments, and Subsystems (SCIS) is a SEMI Special Interest Group chartered to address process-critical components challenges to meet the demands of high-volume manufacturing (HVM) at advanced process nodes. SEMI Special Interest Groups (SIGs) connect SEMI members to discuss and advance specific issues that are important to SEMI Member's business development interests. These SEMI communities provide members a collaborative platform and a collective voice within the electronic industry globally; allow SEMI members access to information on parts of the extended electronic supply chain; and, the SEMI standards and requirements platform to develop the community’s worldwide capability.

There is a great sense of urgency in preparing the supply chain to enable HVM at 7nm and beyond. To date, there is no industry alignment on how defects are measured on various components and sub-components and on how these results are reported. This is especially alarming when several yield excursions are linked to a wide range of component- and subcomponent-induced defectivity. Furthermore, current component and subcomponent defect traceability lack the rigor for advanced technologies, particularly with regard to detectability, sensitivity, and methodology. Finally, while some standards exists, they are often inadequate for addressing advanced process control requirements. In order for the industry to determine what the particle and defectivity limits will be at advanced nodes, there first needs to be an understanding of the current contributions of various process-critical components. Therefore, SCIS activities are focused to establish a baseline for measuring defects introduced by these critical components.

SCIS is structured to address the defectivity issue at both strategic and tactical levels. Subteams were established, based on key stakeholder inputs, to work on component characterization as well as developing a framework for measuring defects.

 

Meanwhile, the SCIS Steering Committee, which includes device maker & foundries as well as major equipment OEMs, provides guidance to these subteams, helps resolve escalated issues, and assists in the recruitment of key stakeholders. Finally, the SCIS Executive Steering provides an oversight and roadmapping functions as well as assists in managing stakeholder engagement.

Each SCIS working group has identified key parameters of their components, particularly those that contribute to defects, while also taking into consideration the applicability to various applications and process areas. The Seals Group is currently working on a method for measuring leak rate for FFKM, a consideration for a seal’s ability to hold vacuum. Once the development of this measurement method is completed, the group plans to focus on chemical resistance, which takes into consideration a seal’s performance when exposed to harsh chemistries.

The Dry Pumps Group is developing a method for measuring vibration & noise as these could potentially be attributed to a pump’s health and, in turn, could potentially lead to component failure. The group also plans to address leak rate as well as exhaust pressure once their work on pump vibration & noise has been completed.

The RF Group is chartered to focus on defectivity parameters related to RF generators. The group is currently focusing on measuring the transient response of RF generators used in semiconductor equipment. The SEMI E135 Standard already provides a test method for RF generator transient response. However, the SCIS RF Group has determined that the Standard will need to be significantly updated to address real world conditions and having this consideration will help in determining the RF generator’s worst case condition response time.  Once the group has completed its major revision of SEMI E135, it will then focus on power measurement on strongly modulated plasma loads. This will ultimately result in the creation of a new standard, as there are currently no industry specifications in place.

As SCIS subteams complete the framework for measuring component defect parameters, these are funneled to the SEMI Standards Program for formal standards development. SCIS members will continue to support document development as these proposals go through the SEMI Standards process.

One of the first accomplishments for SCIS led to the successful major revision of SEMI F51 - Guide for Elastometric Sealing Technology. Published in November 2015, this revision established methods for measuring leachable, ash, outgassing, and total organic content. In 2016, the Seals Group focused on seal cleaning, packaging, and handling. While process controls are established to ensure dimensional accuracy and specification, there is no industry standard on how seals are cleaned, packaged, and handled after they are manufactured. The lack of industry alignment on these final production steps often results in contaminants being introduced into the wafer manufacturing process. By the end of 2016, the group completed the development of the seal cleaning & packaging proposal and transitioned the activity into the SEMI Standards infrastructure, specifically to the F51 Revision Task Force, under the North America (NA) Facilities Technical Committee (TC) Chapter. In early 2017, the proposal (SEMI Draft Document 6105) was issued in the Cycle 1 voting period and will be adjudicated in spring 2017.

The SCIS Gas Delivery Group completed its development of proposed test methods for measuring metallic contamination as well as hydrocarbon contamination for gas delivery systems. The proposal establish a method to extract and measure metallic elements present on the wetted surfaces. The group took a similar approach for hydrocarbon compounds. Their aim was for these test methods to employ out-of-box and as-built components and systems thereby making these approaches more widely accessible. While particle limits for gas delivery components have not yet been clearly defined, these test methods would help establish a baseline on current contribution levels. These proposals were transitioned to the SEMI Standards infrastructure, particularly to the Materials of Construction of Gas Delivery Systems Task Force under the NA Gases TC Chapter.

While some SCIS activities have been completed and are now going through the formal standardization process, there is still much work to be done. For example, the SCIS Liquid Delivery Group is addressing particle, metallic, as well as ionic defect sources. This effort is also coordinated with the High Purity Polymer Materials and Components Task Force which is working on revisions to F57 (addition of filters) and F104 (dynamic particle testing) Standards. Revision to SEMI C79 for particle shedding for high performance filters is also anticipated, but will be carried out by a different SEMI Standards task force.

The SCIS Critical Chamber Components Group is developing measurement approaches for showerhead process characterization and quality check. These include hole diameter/roughness, flatness as well as metrology for particles and metals. The SCIS Valves Group is looking into operational cleanliness and other critical areas for wafer transfer valves, while the Defect Traceability Group is fine-tuning their Information Exchange Model proposal that ensures Key Characteristics are controlled with compliance information easily accessed via a cloud based application.

SCIS subteams meet on a bi-weekly to monthly basis via teleconference while face-to-face meetings convening all SCIS groups are held every quarter. The next SCIS face-to-face meeting is scheduled for May 18 in conjunction with the SEMI Advanced Semiconductor Manufacturing Conference (ASMC) in Saratoga Springs, New York. A face-to-face meeting is also planned during SEMICON West 2017.

Participation in SCIS is open to all SEMI Members. Companies participating in SCIS include (in alphabetical order): Advanced Energy, Applied Materials, Applied Seals, AP Tech, ASM, ASML, Busch Vacuum, CKD, DuPont, Ebara, Edwards, Entegris, Festo, GLOBALFOUNDRIES, Greene Tweed, Horiba, Intel, Kashiyama, KLA-Tencor, Lam Research, Micron, Pall, Parker, PPE, Tokyo Electron, Valqua America, VAT.

 

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March 2, 2017