SEMI International Standards
Standards New Activity Report Form (SNARF)
Date Prepared: 02/01/2016Revised (if Applicable): 11/05/2018

Document Number: 6007
SNARF for: New Standard: Guide for Use of Test Patterns for Characterizing a Deep Reactive Ion Etching (DRIE) Process

Originating Global Technical Committee: MEMS / NEMS
Originating TC Chapter: North America
Task Force (TF) in which work is to be carried out: MEMS Material Characterization Task Force
Note: If a new task force is needed, also submit a task force organization form (TFOF)

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1. Rationale:
a. Describe the need or problem addressed by this activity.
(Indicate the customer, what benefits they will receive, and if possible, quantify the impact on the return on investment [ROI] if the Document is implemented.)
Deep Reactive Ion Etching (DRIE) is widely used in MEMS processes for fabricating high-aspect ratio features. However, each tool type – and often each chamber – has unique recipe settings for optimum etch performance for each material. These settings include gas flows, duration, temperature profile, etc. A designer does typically not know these variables before bringing a design to the foundry. Further, the performance is dependent on open area (OA), i.e., the amount of area subject to the etch process. The OA can range from 1% to 100% (blanket etch). These variables lead to significant costs to both designer and foundry, as the process must be tuned to the specific design and material combination, before production can commence.

Currently, the designer may not have information on how a specific tool at their foundry of choice may perform and it is common that unexpected etch results lead to missed performance target on first silicon. That is, since the designer is limited to using best known methods to achieve the desired feature sizes, the results may not meet requirements.

The guide would provide a standard family of test patterns, with OA ranging from 1% to approximately 50%, to simplify process evaluation, allowing the designer to use the test pattern in a short-loop process. The results of the short-loop would allow the designer to modify their layout to ensure verify that they achieve the desired geometry, with a reduction in time and expense to first functional chips.

MEMS foundries can implement this test pattern, allowing them to incorporate the results into their design guidelines, eliminating the need for customers to use their design as a test pattern for the DRIE process.



b. Estimate effect on industry.
1: Major effect on entire industry or on multiple important industry sectors - identify the relevant sectors
Sector or Company Information: MEMS

c. Estimate technical difficulty of the activity.
III: Difficult - Limited expertise and resources exist and/or achieving consensus is difficult

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2. Scope:
a: Describe the technical areas to be covered or addressed by this Document development activity. For Subordinate Standards, list common concepts or criteria that the Subordinate Standard inherits from the Primary Standard, as well as differences from the Primary Standard:
This standard will describe a family of test patterns useful for characterizing the etch performance of a specific tool/test chamber. The OA of these test patterns are expected to cover the range from 1% to 50% to reflect the most commonly requested etch types from various MEMS device families (gyroscope, accelerometers, microphones, etc.).

In addition, since the use of test masks alone will not be able to provide guidance on the tilt requirement of devices such as gyroscope – one of the main drivers for DRIE in recent years – the task force will consider including test pattern elements that can be evaluated using electrical test methods.

MEMS foundries can implement this test pattern, allowing them to incorporate the results into their design guidelines, eliminating the need for customers to use their design as a test pattern for the DRIE process. In the absence of a standard test method for evaluating this pattern, this document will include a “Related Information” section to discuss metrology for this test pattern.


b: Expected result of activity
New Standard or Safety Guideline (including replacement of an existing Standard or Safety Guideline)

For a new Subordinate Standard, identify the Primary Standard here:




For Standards, identify the Standard Subtype below:
Guide

Miscellaneous (describe below):

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3. Projected Timetable for Completion:

a: General Milestones
a. Activity Start: 12/01/2015b. 1st Draft by: 04/01/2019
c. (Optional) Informational Ballot by: d. Letter Ballot by: 05/01/2019
e. TC Chapter Approval By:07/30/2019

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4. Liaisons with other Global Technical Committees/TC Chapters/Subcommittees/TFs:
a.
List SEMI global technical committees, TC Chapters, subcommittees, or task forces in your or other Regions/Locales that should be kept informed regarding the progress of this activity. (Refer to SEMI Standards organization charts and global technical committee charters and scopes as needed.)
3DP&I

b. List any planned Type I Liaisons with external nonprofit organizations (e.g., SDO) that should receive Draft Documents from Standards staff for feedback during this activity and be notified when the Letter Ballot is issued (refer to Procedure Manual § 7):


c. Intercommittee Ballots:
will be issued – identify the recipient global technical committee(s):

Identify the recipient global technical committee(s):
3D Packaging and Integration
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5. Safety Considerations:
The resulting document is expected:
NOT to be a Safety Guideline

NOTE FOR "to be a Safety Guideline": When all safety-related information is removed from the Document, the Document is NOT technically sound and complete - Refer to Section 15.1 of the Regulations for special procedures to be followed.

NOTE FOR "NOT to be a Safety Guideline": When all safety-related information is removed from the Document, the Document is still technically sound and complete.

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6. Intellectual Property Considerations:
a. For a new Standard or Safety Guideline and for any part to be modified or added in a Revision of published Standards and Safety Guidelines:
the use of patented technology is NOT required.

If "patented technology is intended to be included in the proposed Standard(s) or Safety Guideline(s) " is selected above, then also check one:


b. For Revision, Reapproval, Reinstatement, or Withdrawal of existing Standard(s) and Safety Guideline(s):


c. The body of the Document and any Appendices, Complementary Files, Related Information sections, or Various Materials that may or may not be a part of the Document by reference:



NOTE FORthe use of patented technology or the incorporation of Copyrighted Item(s) is NOT required’: If in the course of developing the Document, it is determined that the use of patented technology or Copyrighted Item(s) is necessary for the Document, the provisions of Regulations § 16 must be followed.

NOTE FORwill incorporate Copyrighted Item’: A copyright release letter must be obtained from the copyright owner prior to publication.

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7. Comments, Special Circumstances:
Original SNARF prepared February 1, 2016, went out for two-week review 03/17/2016 - 03/31/2016. SNARF was approved at the TC Chapter Meeting on 04/04/2016.

SNARF change from Spec to Guide was approved at NA Fall meetings 2018.

SNARF one-year extension made at NA Spring 2019.

Passed A&R Cycle 01-2021
Published as: SEMI MS13


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8. TC Member Review:
took place between (put dates below ) before approval at the TC Chapter Meeting, or

Member Review Start Date; 10/12/2018
Member Review End Date: 10/25/2018

NOTE FOR ‘TC Member Review’ is required by the Regulations for a period of at least two weeks
before approval of a new, or a major revision of an existing, Standard or Safety Guideline. (Refer to Regulations ¶ 8.2.1)
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9. SNARF Approval Dates:
TC Chapter or GCS11/05/2018
Recorded in TC Minutes11/05/2018

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10. SNARF Extension Dates:
TC Chapter Extension Granted on 04/01/2019
Extension Expires on03/30/2020
SNARF DRIE Test Patterns-Distribute(specification).docSNARF DRIE Test Patterns-Distribute(specification).docSNARF Revision 6007 (Specification to Guide).docxSNARF Revision 6007 (Specification to Guide).docxRevision SNARF 6007 (Spec to Guide)_clean.pdfRevision SNARF 6007 (Spec to Guide)_clean.pdfSNARF Revision 6007 (Specification to Guide)_redline.pdfSNARF Revision 6007 (Specification to Guide)_redline.pdf