SEMI International Standards
Standards New Activity Report Form (SNARF)
Date Prepared: 04/01/2012Revised (if Applicable):

Document Number: 5409
SNARF for: New Standard: Guide for Metrology for Measuring Thickness, Total Thickness Variation (TTV), Bow, Warp/Sori, and Flatness of Bonded Wafer Stacks

Originating Global Technical Committee: 3DS-IC
Originating TC Chapter: North America
Task Force (TF) in which work is to be carried out: 3DS-IC Inspection and Metrology
Note: If a new task force is needed, also submit a task force organization form (TFOF)

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.)
Bonded wafer stack (BWS) thickness, total thickness variation (TTV), bow, warp/sori, and flatness metrology is essential before, during, and after the wafer bonding process. These parameters provide meaningful information about the quality of the wafer thinning process (if used), the uniformity of the bonding process, and the amount of bow and warp/sori induced on the wafer stack by the bonding process. The quality of lithography is also dependent on having uniformly flat wafers. Total thickness variation is also critical in bonded wafer manufacturing, since intermittent TSV contact to M2 will occur due to non-planarity. Non-planarity may also affect overlay quality. Subsequently this study can assist producers and users of other wafer bonding processes to develop robust products and conduct meaningful substrate evaluations.

The proposed guideline will provide guidance on key bonded wafer dimensional metrology metrics, along with any limitations and/or issues and needs particular to that technology. The guide will also include applicable ranges for valid measurements where possible.

b. Estimate effect on industry.
2: Major effect on an industry sector - identify the relevant sector
Sector or Company Information:

c. Estimate technical difficulty of the activity.
II: Some Difficulty - Disagreements on known requirements exist but developing consensus is possible

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:
A number of technologies have been developed to measure bonded wafer stack (BWS) thickness, total thickness variation (TTV), bow, warp/sori, and flatness metrology. Examples include, but are not limited to IR laser profiling, white light confocal microscopy, visible and IR interferometry, opto-acoustic metrology, and capacitance metrology. Each technology has unique strengths and weaknesses—some rely on front-side illumination, others on back-side illumination. Some techniques can measure the thicknesses of individual layers in the bonded wafer stack, and some are capable of measuring surface topography. In this activity, we will provide examples of the capabilities and limitations of these technologies and prepare a guide to the use and suitability of these tools for different applications. Recent studies and reports conducted at SEMATECH will be used as part of this guide.

This guide will cover both temporary and permanent bonded wafer stacks.

b: Expected result of activity
New Standard

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

For Standards, identify the Standard Subtype below:

Miscellaneous (describe below):

3. Projected Timetable for Completion:

a: General Milestones
a. Activity Start: 04/03/2011b. 1st Draft by: 09/01/2012
c. (Optional) Informational Ballot by: d. Letter Ballot by: 01/01/2013
e. TC Chapter Approval By:04/01/2013

4. Liaisons with other Global Technical Committees/TC Chapters/Subcommittees/TFs:
List 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 as needed.)
Taiwan 3DS-IC Committee

b. Intercommittee Ballots:

Identify the recipient global technical committee(s):

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 14.1 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.

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 or a copyrighted item(s) 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:
will NOT include copyrighted material

NOTE FOR "the use of patented technology or a copyrighted item(s) is NOT required": If in the course of developing the document, it is determined that patented technology or copyrighted item(s) must be used to comply with the standard or safety guideline, the provisions of Section 15 of the Regulations must be followed.)

NOTE FOR "will include reproduced copyrighted material": A copyright release letter must be obtained from the copyright owner.

7. Comments, Special Circumstances:

8. TC Member Review:

Member Review Start Date; None.
Member Review End Date: None.

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. (See Regulations 8.2.1)
9.. SNARF Approval Dates:
TC Chapter or GCS04/03/2012
Recorded in TC Minutes04/03/2012
Attach Pictures and Files here: