1、JEDEC STANDARD Mark Legibility JESD22B114A (Revision of JESD22B114, March 2008) MAY 2011 JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, and approved through the JEDEC Board of Directors level and subsequently review
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7、. Published by JEDEC Solid State Technology Association 2011 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 This document may be downloaded free of charge; however JEDEC retains the copyright on this material. By downloading this file the individual agrees not to charge for or resel
8、l the resulting material. PRICE: Contact JEDEC Printed in the U.S.A. All rights reserved PLEASE! DONT VIOLATE THE LAW! This document is copyrighted by JEDEC and may not be reproduced without permission. Organizations may obtain permission to reproduce a limited number of copies through entering into
9、 a license agreement. For information, contact: JEDEC Solid State Technology Association 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 or refer to www.jedec.org under Standards and Documents for alternative contact information. JEDEC Standard No. 22B114A -i- TEST METHOD B114A: MARK
10、 LEGIBILITY Foreword This standard is intended for manufacturers and users of solid state devices that incorporate laser or ink based markings. Introduction For conventional ink marking of solid state devices, permanency is the primary concern, and is covered by JESD22-B107. Laser based markings hav
11、e no permanency issues, thus JESD22-B107 does not apply. However, there has been a lot of variability in the readability and legibility of laser based markings, which has highlighted the need for mark legibility requirements. JEDEC Standard No. 22B114A -ii- JEDEC Standard No. 22B114A Page 1 Test Met
12、hod B114A (Revision of Test Method B114) TEST METHOD B114: MARK LEGIBILITY (From JEDEC Board Ballot JCB-08-07 and JCB-11-38, formulated under the cognizance of the JC-14.3 Subcommittee on Silicon Devices Reliability Qualification and Monitoring.) 1 Scope This standard describes a nondestructive test
13、 to assess solid state device mark legibility. The specification applies only to solid state devices that contain markings, regardless of the marking method. It does not define what devices must be marked or the method in which the device is marked, i.e., ink, laser, etc. The standard is limited in
14、scope to the legibility requirements of solid state devices, and does not replace related reference documents listed in this standard. 2 Normative references The following normative documents contain provisions that, through reference in this text, constitute provisions of this standard. The latest
15、editions of the normative documents listed below apply to this standard. ANSI INCITS 182-1990, Bar Code Print Quality Guideline ISO/IEC 15415, Bar Code Print Quality Test Specification ISO/IEC 16022, Data Matrix Bar Code Symbology Specification 3 Informative references The following informative docu
16、ments contain relevant mark legibility discussions that provide helpful supplemental references. CEA-706, Component Marking Standard MIL-STD-130, Identification Marking of U.S. Military Property SAE AS9132, Data Matrix Quality Requirements for Parts Marking 4 Terms and definitions For the purposes o
17、f this standard, the terms and definitions listed below apply: bar code symbol: A symbol that gives information in a code consisting of parallel bars and spaces, each of various specific widths. contrast: The difference in luminance (“brightness”) between the mark and the surrounding device surface.
18、 NOTE Contrast is typically quantified by comparison of minimum and maximum reflectance values. JEDEC Standard No. 22B114A Page 2 Test Method B114 (Revision of Test Method B114) 4 Terms and definitions (contd) data matrix: A two-dimensional bar code matrix symbol. ink mark: A mark, on a device, crea
19、ted using applied ink, paint, or other pigment. laser mark: A mark, on a device, created by using a laser to ablate or melt the device surface, to bond a contrasting labeling material, or to activate a pigmented coating. legibility: The ability of a character or symbol to be read or deciphered. mark
20、 (on a device): One or more symbols and/or characters intended to provide information and located on a surface of a device. NOTE A mark can give information on such items as terminal location, country of origin, manufacturer, date code, lot number, and device identification, e.g., a part number. ove
21、rall symbol grade: The overall quality measure of a two-dimensional bar code symbol determined by machine scanning equipment per guidelines of ISO/IEC 15415 or ANSI INCITS 182-1990. NOTE The grades range from 0 (low) to 4 (high) for ISO/IEC 15415 and from F (low) to A (high) for ANSI INCITS 182-1990
22、. readability: A subjective measure of the ease with which a character or text may be read. reflectance: The ratio of luminous flux reflected from a surface to the luminous flux incident on that surface. 5 Test method 5.1 Sample size Mark legibility is a non-destructive test. The test may be appropr
23、iate for 100% final visual inspection, or it may be deployed on a sample basis, particularly for machine inspection of 2D matrix legibility. Recommended minimum sample basis is 3 lots, 10 samples per lot; a “lot” is a group of devices with the same materials and construction marked within a single m
24、anufacturing run, using the same marking equipment. Sample size and test frequency will typically be determined by supplier/customer agreement. 5.2 Sample preparation Samples shall be representative of production devices in an as-shipped condition and shall not be subjected to any cleaning or surfac
25、e treatment process prior to mark legibility inspection. Normal board-assembly manufacturing processes, or field operating conditions, may degrade mark legibility; examples include permanent conditions, such as epoxy or conformal coating, and temporary conditions, such as flux residue, that can be r
26、emoved by cleaning. If mark legibility inspection is to be conducted following board assembly, removal of non-permanent coatings may first be required. JEDEC Standard No. 22B114A Page 3 Test Method B114A (Revision of Test Method B114) 5 Test method (contd) 5.3 Rework Reworked markings shall meet the
27、 same legibility requirements as non-reworked markings. Although a solid state device that is ink marked may be reworked following legibility inspection, a laser marked device is typically scrapped if it fails legibility requirements. Specific mark rework restrictions, however, are defined by suppli
28、er/customer agreement. 5.4 Apparatus Depending on the specific mark type, and whether bar code symbols are used, the test apparatus needed to assess mark legibility can vary. Legibility evaluation by human visual inspection may require only a light source, or may also include a microscope or other o
29、ptical aid. Legibility assessment by machine typically requires a light source, bar code reader, and quality grading software. 5.4.1 Light source The light source should be matched to the intended inspection method: unaided human inspection, aided visual inspection, or machine scanning equipment. Li
30、ght sources may have a peak light wavelength, e.g., laser, LED, etc., or a broad wavelength spectrum, e.g., incandescent lamp, fluorescent lamp, halogen lamp, etc. Lighting source selection guidance listed in Annex of ISO/IEC 15415 is intended for use with machine scanning equipment, but may also pr
31、ovide helpful background for lighting selection by human visual inspection. The default angle of incidence for the light source is 45, but it may be adjusted to improve apparent contrast between the mark and the surrounding device surface using the selected inspection method. 5.4.2 Unaided (no optic
32、al assistance) human visual inspection The mark shall be viewed at a distance of 15-30 cm. A dedicated work area light source at a 45 nominal incidence angle is recommended, but normal room lighting conditions (200-600 lux, typ.) may prove adequate. 5.4.3 Aided human visual inspection Using a stereo
33、 microscope (or other optical device), the mark shall be viewed at a maximum distance of 18 cm, and a maximum magnification of 3X. Minimum inspection distance will typically be determined by the focal distance of the optical device. A dedicated light source is recommended. The sample should be posit
34、ioned such that the viewing angle is less than 15, relative to the device surface perpendicular, to maintain a uniform focal plane across the mark surface; however, the viewing angle may be adjusted (see Figure 1) to improve apparent contrast between the mark and the surrounding device surface if th
35、e lighting sources angle of incidence (45 typ.) is otherwise fixed. JEDEC Standard No. 22B114A Page 4 Test Method B114 (Revision of Test Method B114) 5.4 Apparatus (contd) 5.4.3 Aided human visual inspection (contd) Figure 1 Viewing angle adjustment 5.4.4 Bar code reader The bar code reader shall co
36、mply with the aperture and quality grading requirements of ISO/IEC 15415 or ANSI INCITS 182-1990. 6 Legibility requirements 6.1 Human visual inspection (Unaided and Aided) All identifying characters and symbols of the mark shall be legible by operator assessment using the appropriate Section 5 test
37、method. A character or digit is unacceptable if inspection leaves a doubt as to its identity. The quality of the assessment depends on the operator fitness. This standard assumes the operator is appropriately trained to make the inspection, has normal, corrected visual acuity (20/20), and is free of
38、 fatigue or other physical effects which could diminish judgment capability. Documentation of inspection distance, magnification and lighting conditions may be required per supplier/customer agreement. 6.1.1 Character size The minimum character size for a particular device mark will typically dictat
39、e whether human visual inspection requires the use of an optical aid such as a microscope. This standard does not specify what character set (OCR-A, OCR-B, etc.) or minimum font size (2, 5, etc.) should be used, or whether a mark is required at all; it defines only the legibility requirements. JEDEC
40、 Standard No. 22B114A Page 5 Test Method B114A (Revision of Test Method B114) 6.1 Human visual inspection (Unaided and Aided) (contd) 6.1.2 Surface finish Although the surface texture, surface composition and color may significantly affect the contrast between the mark and the surrounding device sur
41、face, this standard does not specify what means shall be employed to enhance the legibility of the mark. Generally, a dark, matte finish will minimize reflectance, and a light, polished surface will increase reflectance; the difference in reflectance between these surface types will enhance contrast
42、 and mark legibility. 6.1.3 Mark defects Any of the following mark defects which render the marking illegible or unreadable shall be cause for rejection; some of these defects may not apply to all mark types. Bridging: A portion of the character is bridged by excess ink, yielding an unintended chara
43、cter, e.g., a “5” or “G” appearing as a “6” due to ink bridging within the character elements. Distorted mark: A character or symbol appears wavy, or undulating. Double mark: A marking appears twice on the same device in close proximity to the original mark. Faded mark: Fading of an ink mark, or ins
44、ufficient etch of an ablative laser mark. Incomplete/missing mark: Part or all of the mark text is missing, when compared to the specification requirement. Misaligned mark: Part or all of the mark text is misaligned, when compared to the specification requirement. Scratches: Scratches that alter the
45、 form and intended legibility of the mark. Smearing/blurring: A character or symbol appears out of focus. 6.2 Machine inspection In addition to character and general symbol elements, a bar code may also be included in the device mark. The bar code is typically a two-dimensional (2D) matrix, followin
46、g Error Correction Code 200 (ECC 200) requirements, but other 2D error correction codes, or a one-dimensional bar code, may alternatively be used. Typically, human visual inspection is used for the character and general symbol elements, and a bar code reader is used for legibility inspection of the
47、2D matrix. The 2D matrix shall meet a minimum overall symbol grade of 1.5 or C, per the bar code print quality specification of ISO/IEC 15415 or ANSI INCITS 182-1990, respectively. Typically, the lowest cost scanning equipment works effectively when the overall symbol grade is high; hence, effort sh
48、ould be made to exceed the minimum overall symbol grade requirements of this specification, wherever feasible. Factors affecting the overall 2D matrix symbol grade include symbol contrast, decodability, pattern defects, edge determination, reflectance uniformity in the light/dark regions, pattern no
49、n-uniformity, etc. Annex C of ISO/IEC 15415 provides an extensive list of possible causes for a low symbol grade. JEDEC Standard No. 22B114A Page 6 Test Method B114 (Revision of Test Method B114) 6.2 Machine inspection (contd) Specific inspection distance, equipment capability, lighting source, light incidence angle, aperture, software, etc., can also affect the overall symbol grade and should be documented. ISO/IEC 15415 provides a specific reporting format of the overall symbol grade, including aperture, light and angle. ANSI INCITS 182-1990 overall symbol grade reporting requ
