Overview
IEC 60191-6-3:2000 - "Mechanical standardization of semiconductor devices - Part 6-3" - defines standardized measuring methods for package dimensions of quad flat packs (QFP) classified as Form E. This IEC first-edition technical standard sets out how to measure physical package features for surface-mounted semiconductor device packages, specifying datum definition, measurement procedures and representative values for dimensions that are difficult or destructive to measure.
Key topics and technical requirements
The standard addresses practical, repeatable measurement practices for QFP packages, including:
- Datum definition and orientation: how to establish datum lines (A, B) by connecting centres of opposite sides and correcting skew so axes are rectangular.
- Overall/package width and length (HE / HD / D / E): measurement with the package mounted on a surface plate, tolerance ranges (t, f) about theoretical centers.
- Mounting height (A) and body thickness (A2): measuring from seating plane to highest point, and thickness between tangent planes.
- Stand-off (A1): distance from seating plane to the package’s lowest point.
- Lead geometry: lead widths (b, b1), lead thicknesses (c, c1) - defined near tip (0.1–0.25 mm) and measured before/after plating as applicable.
- Soldered portion length (Lp): measured in mounting direction from a defined cross-point to lead tip.
- Positional tolerance of terminal tips: method to obtain lead-tip positions 0.1 mm inside the tip and compute deviations from theoretical centres.
- Coplanarity (y): how to compute a virtual plane from three lowest leads and measure maximum distance of other leads from that plane.
- Lead flat-angle (θ): method using two height measurements (0.05 mm and 0.25 mm inside tip) and arctangent to derive the flat portion angle.
Normative reference: IEC 60191-6:1990 for definitions and general rules.
Applications and users
IEC 60191-6-3 is intended for professionals involved in:
- PCB and package design validation for quad flat pack (QFP) components
- Quality control and incoming inspection in semiconductor assembly and contract manufacturing
- Mechanical engineering within semiconductor suppliers and OEMs ensuring dimensional compatibility, solderability, and assembly reliability
- Test labs and standards compliance teams performing dimensional audits or creating outline drawings for surface-mounted packages
Using these methods improves interchangeability, reduces assembly errors, and supports accurate footprint and tolerancing decisions.
Related standards
- IEC 60191-6:1990 - General rules for preparation of outline drawings of surface-mounted packages (normative reference)
- IEC vocabulary and symbol standards (e.g., IEC 60050, IEC 60027, IEC 60417) are relevant for terminology and symbols referenced in the standard.
Keywords: IEC 60191-6-3, QFP measuring methods, quad flat pack dimensions, surface mounted semiconductor packages, coplanarity, mounting height, lead width, positional tolerance.