Overview
IEC 60191-6-4:2003 - part of the IEC 60191 series - specifies measuring methods for package dimensions of ball grid array (BGA) surface-mounted semiconductor device packages. It defines how to determine primary datums, measurement procedures and dimension definitions used when preparing outline drawings and guaranteeing dimensional values to users. The standard applies to both BGA Type 1 (ball datum) and BGA Type 2 (body datum) packages and supports manual and automated measurement methods.
Key Topics
- Scope and purpose
- Standardizes measuring methods for BGA package dimensions used in outline drawings and mechanical specifications.
- Datums and reference planes
- Datum S (seating plane): defined by either triangulation of the tallest three balls (must encompass the package centre of gravity) or by a least squares method (LSM) plane shifted to the bottom of the lowest ball.
- Datum A and B: orthogonal axes derived from package side centres; different construction for Type 1 (ball-based) and Type 2 (body-based).
- Defined dimensions and measurement methods
- Package center tolerance (w) - tolerance of centre position for length and width; measured by tangential parallels to package profile while seated on the surface plate.
- Edge profile tolerance (v) - profile range of package edge surfaces; measured via best-fit squares/rectangles to the package perimeter.
- Mounting height (A) - height from seating plane to the top of the package (includes warpage/inclination).
- First stand-off (A1) and Second stand-off (A4) - distances from datum S to the lowest package point (excluding cavity) and to the lowest cavity point respectively (LSM used for datum S).
- Ball parameters - ball diameter (b), ball centre position (X), ball coplanarity (y), package top flatness (y1) - all with specified measuring techniques and figures.
- Measurement approach
- Allows both manual and automated measurement. If a dimension is difficult to measure, the standard permits a best alternative method to be designated.
Applications
IEC 60191-6-4 is used by:
- Package mechanical designers and IC manufacturers - to define and communicate BGA mechanical tolerances.
- Quality control and test laboratories - for acceptance testing and incoming inspection of BGA parts.
- PCB designers and assemblers - to ensure footprint compatibility and soldering reliability (coplanarity, stand-off).
- Contract manufacturers and suppliers - to verify supplier data and reconcile mechanical drawings with physical parts.
Adopting these measurement rules helps reduce assembly defects, improve interchangeability of parts and standardize mechanical specifications across the supply chain.
Related Standards
- Normative reference: IEC 60191-6:1990 (General rules for the preparation of outline drawings of surface-mounted semiconductor device packages).
- See the IEC catalogue for consolidated editions, amendments and related mechanical standardization documents for semiconductor devices.
Keywords: IEC 60191-6-4, BGA measuring methods, ball grid array dimensions, semiconductor device packages, package datums, coplanarity, mounting height.