MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第473页

MIL-STD-883F METHOD 2035 19 August 1994 1 METHOD 2035 ULTRASONIC INSPECTION OF TAB BONDS 1. Purpos e . The purpos e of thi s method i s to det ect unbonded and ins uffi cient ly bonded si tes i n TAB (Tape automat ed bon…

MIL-STD-883F

METHOD 2032.2

18 June 2004

Class H Class K

3.4.4 Foreign material defects "low magnification"

No element shall be acceptable that exhibits:

a. For mounted and unmounted elements, unattached a. Same as class H.

conductive foreign material on the surface of

the element that is large enough to bridge

operating metallization paths.

NOTE: All foreign material shall be considered

to be unattached unless otherwise verified to

be attached. Verification of attachment shall

be accomplished by a light touch with a

mechanical device (i.e., needle, probe, pick,

etc.) or by a suitable cleaning process

approved by the acquiring activity, or by a

nominal gas blow (approximately 20 psig).

Removal of unattached foreign material may be

attempted using the techniques for

verification of attachment discussed above.

b. Liquid droplets, ink drops, or chemical stains b. Same as class H.

that appear to bridge unglassivated

metallization.

c. Attached foreign material that covers greater c. Same as class H.

than 25 percent of a bonding pad area.

4. SUMMARY

. The following details shall be specified in the applicable acquisition document:

a. Class H or class K visual requirements.

b. Where applicable, any conflicts with element design, topology or construction (see 3).

c. Where applicable, gauges, drawings and photographs that are to be used as standards for operator

comparison (see 2).

d. Where applicable, magnifications other than those specified (see 3).

MIL-STD-883F

METHOD 2035

19 August 1994

METHOD 2035

ULTRASONIC INSPECTION OF TAB BONDS

1. Purpose

. The purpose of this method is to detect unbonded and insufficiently bonded sites in TAB (Tape automated

bonding) devices in the open package condition, through the measurement of bond area by means of Scanning Laser

Acoustic Microscope (SLAM) techniques. It establishes methods and criteria for ultrasonic inspection of these TAB

semiconductor devices.

NOTES:

1. For various metallurgical constitutions, absolute strengths expressed as pull strengths per unit area of bond differ.

A scalar equivalency must be established for each alloy and process, to relate bond area to anticipated bond

strength.

2. The term TAB bond in this document refers to one of the multiplicity of bonds, inner lead (ILB) or outer lead (OLB)

formed by a tape automated bonding (TAB) process. In the case of ILB, it refers to that area of the device

defined by the intersection of the beam lead, the semiconductor bonding pad area, and the contact outline of the

thermode or fixture performing the bond, in the horizontal plane, and refers to all interfaces within that area

between the semiconductor die surface and the beam lead. In the case of OLB, it refers to that area of the device

defined by the intersection of the beam lead, the substrate bonding pad area, and contact outline of thermode or

fixture performing the bond, in the horizontal plane, and refers to all interfaces within that area between the

substrate surface and the beam lead.

3. The terms ultrasonic inspection and SLAM as used in this document refer to the process and instrument

performing high frequency ultrasonic inspection and produce grey-scale images of the internal features of devices

by means of scanning laser acoustic microscopy, and by which bond area measurement may be performed.

2. Apparatus

. The apparatus and materials for this evaluation shall include:

a. Ultrasonic imaging equipment of the scanning laser acoustic microscope type, of frequency and resolution

sufficient to penetrate the bond area and render an image which discloses the size and shape of the bond area

with a linear dimensional allowance no greater than 20 percent of a bond dimension. Frequency is dictated by

consideration of the wavelength of sound in the materials and the limit of resolution. Whereas lower frequencies

have been used for inspection of larger scale device types, the present size of TAB sites requires frequencies of

from one hundred to several hundred megahertz.

b. A visual output/storage device. A method of producing, displaying, and storing a scale image of adequate grey-

scale range (minimum of 64 levels) shall be used. Such device may include a grey-scale printer/plotter, or

preferably CRT display with an image digitizer capable of rendering images in digital code for bulk media storage

and retrieval, and algorithmic processing and evaluation. The images so stored shall be suitable for manual, or

preferably, automated analysis. The output devices shall be capable of producing and storing the images to a

spatial and grey-scale resolution at least equal to the resolution of their acquisition by the ultrasonic imaging

equipment. The output/storage device must be capable of presenting, storing, and retrieving image label

information.

3. Procedure

. The equipment used shall be adjusted as necessary to obtain satisfactory images of good contrast to

achieve maximum image detail within the sensitivity requirements of the bond type being examined. The appropriate

operator methodology will be used to insure adequate positioning and insonification (irradiation by ultrasound) of the device

for purposes of producing its image. Additional protocols will be followed as required. The normal intrinsic strength of the

bond metallurgy shall be known and established, and the metallurgy of the devices to be tested should be qualified as in

agreement with that strength.

MIL-STD-883F

METHOD 2035

19 August 1994

3.1 Calibration of the instrument. When specified, at least one device of the type and construction to be tested shall be

available to set up the ultrasonic inspection equipment and peripherals. The device may be a scape non-operational device

with TAB bonded leads which will be used to identify device landmarks and ensure the equipment is properly functional.

3.2 Labeling and identifying

. The devices tested and the image records made of them shall be labeled in a standard

format to include the following information:

a. Device manufacturer's name or code identification number.

b. Device type or part number.

c. Production lot number and/or inspection date code lot number.

d. Ultrasonic image view number and date; to include description or code for the region or bond

number (s) viewed.

e. Device serial/cross reference number if applicable.

f. Ultrasonic operator identification.

3.3 Serialized devices

. When device serialization is required, each device shall be readily identifiable by a serial number,

and this serial number must be included in a form readable in the stored image. In the event of a skipped piece in the

serialization, a blank space representing the skipped piece, and labeled with its serial number should appear in the storage

medium. In the event of a large contiguous range of skipped pieces, a similar blank space advising of the range of pieces

skipped should appear in the storage medium in place of the large physical space of the many skips.

3.4 Data back-up

. When required, data back-up shall be specified from a choice of multiple floppy disk, multiple track

data tape, or a video format tape, or other options having sufficient volume, resolution, speed, and reliability to suit the

requirements for storage and labeling.

3.5 Mounting

. The devices shall be mounted for ultrasonic inspection in a fixture which insures correct positioning in all

dimensions, and adequately safeguards the potentially fragile bonds from mechanical contact with any substance other than

the coupling fluid. Positioning thereafter must continue in a fashion which continues the above condition, and furthermore

exposes each inspected bond area to the correct acoustic environment and portion of the instrumental field.

3.6 Angle of insonification

. The angle of insonification must be specified by prior analysis, and if the mounting fixture is

goniometrically agile it must be set to the correct angle by adjustment or selection.

3.7 Conditions of operation

. Adjustments, selections, options, and settings used in the performance of the ultrasonic

inspection must be recorded if they are of a nature critical to the proper operation of equipment; not to be recorded are those

casual adjustments which are done as an obvious matter of course, and the performance of which are guided by such rules

as trimming for maximum, minimum, or optimum, and which are not controlled by calibrated interfaces.

3.8 Operating personnel

. Operating personnel shall have a basic familiarity of the nature of sound and the use of

ultrasonic instruments in the inspection of devices. They shall be specifically trained and certified in the operation of the

ultrasound and peripheral equipment used so that defects revealed by the method can be validly interpreted and compared

with applicable standards.