JEDEC Standard No. 217A.01
-i-
Test Method 217A
(Revision of Test Method 217.01)
TEST METHODS TO CHARACTERIZE VOIDING IN PRE-SMT
BALL GRID ARRAY PACKAGES
CONTENTS
Page
1
Scope ............................................................................................................................................................ 1
2 Terms and Definitions ................................................................................................................................ 2
3 Normative References ................................................................................................................................ 3
4 Ball Attach Process Flow............................................................................................................................ 4
5 Types of Solder Voids ................................................................................................................................. 5
6 Solder Void Metrologies ............................................................................................................................. 6
6.1 2-D X-ray...................................................................................................................................................... 6
6.1.1 2-D X-Ray Tool Requirement/Limitation .................................................................................................... 7
6.2 3-D Computer Tomography X-ray ............................................................................................................... 9
6.2.1 3-D CT X-Ray Tool Requirement/Limitation .............................................................................................10
6.3 BGA Void Measurement Using 5DX Laminography..................................................................................11
6.3.1 Image Acquisition Setup .............................................................................................................................11
6.3.2 Surface Mapping to Compensate for Warpage ............................................................................................11
6.3.3 Setting Slice Heights ...................................................................................................................................13
6.3.4 Voiding Algorithm Setup ............................................................................................................................13
6.3.5 Cross Section ...............................................................................................................................................15
6.4 BGA Void Characterization Through Post BGA Ball Shear Pad Fracture Surface Inspection ...................19
7 Preferred Solder Void Metric ...................................................................................................................19
8 Preferred Solder Void Metrology .............................................................................................................22
9 Sampling Plan ............................................................................................................................................23
10 Void Guideline ...........................................................................................................................................23
Annex A Calculation of Cumulative % Void Area Within Solder Balls (1 or Multiple Voids in the X-Ray
Image) .........................................................................................................................................................24
A.1 Comparison of Cumulative vs. % Void Area for Largest Void for Three Examples of Voids in Solder
Balls .............................................................................................................................................................25
Annex B 2-D X-Ray Void Detection to 3-D Correlation X-ray Correlation Study ..............................................26
Annex C Solder Void Growth Characterization Results ......................................................................................30
C.1 Solder Void Growth Characterization - Study 1 ..........................................................................................31
C.2 Solder Void Growth Characterization - Study 2 ..........................................................................................32
C.3 Solder Void Growth Characterization - Study 3 ..........................................................................................34
C.4 Justification of Proposed 15% Cumulative Void Area Guideline for BGA Balls Post Ball Attach ............36
Annex D (Informative) Differences Between JESD217A and the Prior Versions ................................................37
Figures Page
Figure 1 — Illustration of Unfilled Microvia (a) Out-of-Scope vs. Filled Microvia (b) In-Scope of Document ........... 1
Figure 2 — BGA Ball Attach Process Flow Diagram .................................................................................................... 4
Figure 3 — Typical Size and Location of Various Types of Voids in a BGA Solder Joint ........................................... 6
Figure 4 — Illustration of X-ray Setup and its Orthogonal Alignment to Test Sample ................................................. 7
Figure 5 — Example of Contrasting in Grey Scaling (0% to 30% Gray) Permitting Detection of Solder Voids .......... 8
Figure 6 — Illustration of the 3-D X-ray Scanning Process and Void Diameter Computation.....................................10
Figure 7 — Schematic Diagram of a 5DX X-ray Laminography Tool .........................................................................11
Figure 8 — Surface Map Location on the Bottom Side of the Package Substrate ........................................................12
Figure 9 — Example of a Carrier Used to Support the Test Sample During 5DX Laminography Measurements .......12
Figure 10 — Approximate Location of Three Slices for a BGA Ball Across Which the Cumulative % Void Area is
Determined by the 5DX Laminography Tool ..........................................................................................13
Figure 11 — Example of an Image of 5DX Laminography Tool Which Shows the Solder Balls and the Voids Within
Them (Yellow) .........................................................................................................................................14
Figure 12 — Example of Region Size per Slice ............................................................................................................14
Figure 13 — Sequence of Grinding and Polishing Steps for Cross-Sectioning a BGA Package in the X-Y Plane ......15
Figure 14 — Cross-Section Views at Two Magnifications, Illustrating Voids in the BGA Balls. ................................16
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