MIL- STD-883F 2004 TEST METHOD STANDARD MICROCIRCUITS - 第268页

MIL-STD-883F METHOD 2012.7 1 June 1993 2 3.1.1. 2 Stud-mounted and c ylindr ical axial lead devi ces. Stud-mount ed and cyli ndric al axial lead devi ces, unless otherwi se spec ifi ed, shal l have one view t aken wit h …

MIL-STD-883F

METHOD 2012.7

1 June 1993

METHOD 2012.7

RADIOGRAPHY

1. Purpose

. The purpose of this examination is to nondestructively detect defects within the sealed case, especially

those resulting from the sealing process and internal defects such as foreign objects, improper interconnecting wires,

and voids in the die attach material or in the glass when glass seals are used. It establishes methods, criteria, and

standards for radiographic examination of semiconductor and hybrid devices.

NOTE: For certain device types, opacity of the construction materials (packages or internal attachment) may

effectively prevent radiographic identification of certain types of defects from some or all possible viewing angles. This

factor should be considered in relation to the design of each device when application of this test method is specified.

2. Apparatus

. The apparatus and material for this test shall include:

a. Radiographic equipment with a sufficient voltage range to penetrate the device. The focal distance shall be

adequate to maintain a sharply defined image of an object with a major dimension of 0.0254 mm (0.001 inch).

b. Radiographic film: Very fine grain industrial X-ray film grade, either single or double emulsion.

c. Radiographic viewer: Capable of 0.0254 mm (0.001 inch) resolution in major dimension.

d. Holding fixtures: Capable of holding devices in the required positions without interfering with the accuracy or ease

of image interpretation.

e. Radiographic quality standards: Capable of verifying the ability to detect all specified defects.

f. Film holder: A 1.6 mm (0.0625 inch) minimum lead-topped table or lead-backed film holders to prevent back

scatter of radiation.

3. Procedure

. The X-ray exposure factors, voltage, milliampere and time settings shall be selected or adjusted as

necessary to obtain satisfactory exposures and achieve maximum image details within the sensitivity requirements for

the device or defect features the radiographic test is directed toward. The X-ray voltage shall be the lowest consistent

with these requirements and shall not exceed 200 kV.

3.1 Mounting and views

. The devices shall be mounted in the holding fixture so that the devices are not damaged or

contaminated and are in the proper plane as specified. The devices may be mounted in any type of fixture and masking

with lead diaphragms or barium clay may be employed to isolate multiple specimens provided the fixtures or masking

material do not block the view from X-ray source to the film of any portion of the body of the device.

3.1.1 Views

3.1.1.1 Flat packages, dual-in-line packages, hybrid packages, and single ended cylindrical devices

. Flat packages,

dual-in-line packages, hybrid packages, and single ended cylindrical devices, unless otherwise specified, shall have one

view taken with the X-rays penetrating in the Y direction as defined on figures 1 and 2 of MIL-STD-883, GENERAL

REQUIREMENTS. When more than one view is required, the second and third views, as applicable, shall be taken with

the X-rays penetrating in the Z and X direction respectively (either Z or X for flat packages). The die/cavity interface

shall be positioned as close as possible to the film to avoid distortion.

MIL-STD-883F

METHOD 2012.7

1 June 1993

3.1.1.2 Stud-mounted and cylindrical axial lead devices. Stud-mounted and cylindrical axial lead devices, unless

otherwise specified, shall have one view taken with the X-rays penetrating in the X direction as defined on figures 1 and

2 of MIL-STD-883, GENERAL REQUIREMENTS. When more than one view is required, the second and third views, as

applicable, shall be taken with the X-rays penetrating in the Z direction and at 45° between the X and Z direction. The

die/cavity interface shall be positioned as close as possible to the film to avoid distortion.

3.2 Radiographic quality standard

. Each radiograph shall have at least two quality standards exposed with each view,

located (and properly identified) in opposite corners of the film. These penetrameters shall be of a radiographic density

nearest the density of the devices being inspected. The radiographic quality standard shall consist of a suitable ASTM

penetrameter as described in the DOD adopted standard ASTM E 801 Standard Practice for Controlling Quality of

Radiographic Testing of Electronic Devices, or equivalent.

3.3 Film and marking

. The radiographic film shall be in a film holder backed with a minimum of 1/16 inch lead or the

holder shall be placed on the lead topped table. The film shall be identified using techniques that print the following

information, photographically, on the radiograph:

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

b. Device type or Part or Identifying Number.

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

d. Radiographic film view number and date.

e. Device serial or cross reference numbers, when applicable.

f. X-ray laboratory identification, if other than device manufacturer.

3.3.1 Nonfilm techniques, when specified

. The use of nonfilm techniques is permitted if the equipment is capable of

producing results of equal quality when compared with film techniques, and all requirements of this method are complied

with, except those pertaining to the actual film. Radiographic quality standards, as specified in 3.2, may be used at the

beginning and end of each inspection lot if equipment settings are not modified.

3.3.2 Serialized devices

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

number. They shall be radiographed in consecutive, increasing serial order. When a device is missing, the blank space

shall contain either the serial number or other X-ray opaque object to readily identify and correlate X-ray data. When

large skips occur within serialized devices, the serial number of the last device before the skip and the first device after

the skip may be used in place of the multiple opaque objects.

3.3.3 Special device marking

. When specified (see 4.c), the devices that have been X-rayed and found acceptable

shall be identified with a blue dot on the external case. The blue dot shall be approximately 1.6 mm (0.0625 inch) in

diameter. The color selected from FED-STD-595 shall be any shade between 15102-15123 or 25102-25109. The dot

shall be placed so that it is readily visible but shall not obliterate other device marking.

3.4 Tests

. The X-ray exposure factor shall be selected to achieve resolution of 0.0254 mm (0.001 inch) major

dimension, less than 10 percent distortion and an "H" and "D" film density between 1 and 2.5 in the area of interest of the

device image. Radiographs shall be made for each view required (see 4).

3.5 Processing

. The radiographic film manufacturer's recommended procedure shall be used to develop the exposed

film, and film shall be processed so that it is free of processing defects such as fingerprints, scratches, fogging, chemical

spots, blemishes, etc.

MIL-STD-883F

METHOD 2012.7

1 June 1993

3.6 Operating personnel

. Personnel who will perform radiographic inspection shall have training in radiographic

procedures and techniques so that defects revealed by this method can be validly interpreted and compared with

applicable standards. The following minimum vision requirements shall apply for personnel inspecting film:

a. Distant vision shall equal at least 20/30 in both eyes, corrected or uncorrected.

b. Near vision shall be such that the operator can read Jaeger type No. 2 at a distance of 16 inches, corrected or

uncorrected.

c. Vision tests shall be performed by an oculist, optometrist, or other professionally recognized personnel at least

once a year. Personnel authorized to conduct radiographic tests shall be required to pass the vision test specified

in 3.6 a and b.

3.7 Personnel safety precautions

. The safety precautions described in National Institute of Standards and

Technology (NIST) Handbook 76 - X-ray Protection; NIST Handbook 73 - Protection Against Radiations From Sealed

Gamma Sources; Nuclear Regulatory Commission Book Title 10, Part 20 - Standard for Protection Against Radiation,

Part 30 - Licensing of By-Product Material, Part 31 - Radiation Safety Requirements for Radiographic Operations, shall

be complied with when applicable.

3.8 Interpretation of radiographs

. Utilizing the equipment specified herein, radiographs shall be inspected to

determine that each device conforms to this standard and defective devices shall be rejected. Interpretation of the

radiograph shall be made under low light level conditions without glare on the radiographic viewing surface. The

radiographs shall be examined on a suitable illuminator with variable intensity or on a viewer suitable for radiographic

inspection on projection type viewing equipment. The radiograph shall be viewed at a magnification between 6X and

25X. Viewing masks may be used when necessary. Any radiograph not clearly illustrating the features in the

radiographic quality standards is not acceptable and another radiograph of the devices shall be taken.

3.9 Reports of records

3.9.1 Reports of inspection

. For class S devices, or when specified for other device classes, the manufacturer shall

furnish inspection reports with each shipment of devices. The report shall describe the results of the radiographic

inspection, and list the purchase order number or equivalent identification, the PIN, the date code, the quantity

inspected, the quantity rejected, and the date of test and which devices utilize the note in 3.10.2.1. For each rejected

device, the PIN, the serial number, when applicable, and the cause for rejection shall be listed.

3.9.2 Radiograph submission

. Photographic reproduction of complete radiographs may be submitted, but artistic

renditions are not acceptable.

3.9.3 Radiograph and report retention

. When specified, the manufacturer shall retain a set of the radiographs and a

copy of the inspection report. These shall be retained for the period specified.

3.10 Examination and acceptance criteria for monolithic devices

3.10.1 Device construction

. Acceptable devices shall be of the specified design and construction with regard to the

characteristics discernible through radiographic examination. Devices that deviate significantly from the specified

construction shall be rejected.

3.10.2 Individual device defects

. The individual device examination shall include, but not be limited to, inspection for

foreign particles, solder or weld "splash", build-up of bonding material, proper shape and placement of lead wires or

whiskers, bond of lead or whisker to semiconductor element and lead or whisker to terminal post, semiconductor

metallization pattern, and mounting of semiconductor element. Any device for which the radiograph reveals any of the

following defects shall be rejected: