How to test bonds » Lead integrity » MIL-STD-883 method 2004.7 lead integrity

Page 5/9: Test condition B2 - Lead fatigue

  1. PURPOSE

    This test is designed to check the resistance of the leads to metal fatigue.

  2. APPARATUS

    Attaching devices, clamps, supports, or other suitable hardware necessary to apply a repeated bending stress through the specified bend angle.

  3. PROCEDURE

    Each lead or terminal to be tested shall be subjected to a force as specified in 3.1 through 3.7, as applicable. Each lead shall be tested in the same direction through the specified arc in one direction and returned to the approximate original position. All arcs shall be made in the same plane without lead restriction. A test cycle shall be completed in 2 to 5 seconds. For devices with rectangular or ribbon leads, the plane of the arcs shall be perpendicular to the flat plane of the lead. The test shall not be applied to end leads of packages where its application will apply primarily torsion forces at the lead seal.

    1. Direction of bends

      Test leads shall be bent in the least rigid direction. If there is no least rigid direction, they may be bent in any direction. No lead shall be bent so as to interfere with another lead. If interference is unavoidable, the test lead shall be bent in the opposite direction to the angle specified and returned to its normal position.

    2. Procedure for pre-formed leads

      When normally straight leads are supplied in a pre-formed condition (including the staggered lead dual-in- line configuration), the lead forming operation shall be considered an acceptable lead fatigue test in place of that specified, provided the lead forming has been done after lead plating and the forming is at least as severe in permanent lead deformation as the specified bending.

    3. Procedure for packages with Flexible leads

      For flexible rectangular leads or round leads, the test force shall be 0.085kg ±0.009 kg (3oz ±0.3 ounces). Each lead shall be tested for three 90° ±5° arcs, unless otherwise specified.

    4. Procedure for packages with Semi-flexible leads

      For semi-flexible rectangle leads or round leads, the test force shall be 0.229kg ±0.014 kg (8oz ±0.5 ounces). Each lead shall be tested for three 90° ±5° arcs, unless otherwise specified.

    5. Procedure for dual-in-line and pin grid array package leads.

      1. Dual-in-line (platform, side brazed, bathtub) package leads are leads normally aligned in parallel at a 90° angle from the bottom of the package during insertion. Dual-in-line package leads shall be bent three times inward through an angle sufficient to cause the lead to retain a permanent bend (i.e., after stress removal) of at least 15°. For configuration 1 and 2, the angle of bend shall be measured from the lead extremities to the first bend (see figure 2004-1), for configuration 3, the angle of bend shall be measured from the lead extremities to the seating plane (see figure 2004-1).

      2. Pin grid array packages shall have the leads required for testing from the outside row of leads on opposite sides bent three times through an angle sufficient to cause the lead to retain a permanent bend (i.e., after stress removal) of at least 15°. The angle of bend shall be 15° from normal and the bend shall be made at the approximate seating plane. At the completion of the initial bend, the leads shall be returned to their approximate original position.

    6. Figure 2004-1. Angle of bend for dual-in-line package configurations

      MIL-STD-883J 2004.7 Figure 2004-1 Angle of bend for dual-in-line package configurations

    7. Optional procedure for Semi-Flexible and Flexible leads

      As an option for all lead sizes, a force as determined by the following formula, unless otherwise specified, shall be applied to each lead to be tested for 90 degrees ±5 degree arcs of the device. All other conditions of section 3.3. and 3.4 shall apply. The test weight shall be calculated as follows: Weight = (area in square inches) x 2.1 % x (UTS in psi) x 453.6 grams/lb. Where UTS in psi is the ultimate tensile strength (UTS) for a particular material. Typical value for kovar, alloy 42 and copper materials are listed below. The UTS for other materials can be found in vendor data sheets. The result shall be rounded to the nearest whole number.

      MaterialUTS in psi
      Kovar75000
      Alloy 4271000
      Copper 10143,500
      Copper 11031,900
       
    8. Procedure for rigid leads or terminals

      Testing of rigid leads or terminals is not required.

    9. Failure criteria

      When examined using magnification between 10X and 20X after removal of stress, any complete breakage (e.g. separation of the lead from the body) shall be considered a failure.

  4. SUMMARY

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

    1. Force to be applied to the lead, if other than above (see 3).

    2. Number of cycles, if other than above (see 3).

    3. Maximum bend angle, if other than above (see 3).

    4. Number and selection of leads (terminals), if different from above.

    5. Post test measurements, if applicable (see 3.8).

Continue to read:

Previous page: Test condition B1 - Bending stress

Next page: Test condition C1 - Lead torque

How to test bonds?

Lead integrity

All XYZTEC bond testers can be used for lead integrity testing. The MIL standard on this page describes the procedure in technical language. Our lead integrity test type page illustrates the test conditions A, B1, B2, C1, C2 and D with real examples. Click here to go there.

MIL-STD-883 method 2004.7 consists of 9 pages:

  1. Lead integrity
  2. A - Tension
  3. A1 - Lead braze integrity
  4. B1 - Bending stress
  5. B2 - Lead fatigue
  6. C1 - Lead torque
  7. C2 - Stud torque
  8. D - Solder pad adhesion for leadless chip carrier and similar devices
  9. E - Lead plating integrity

Lid torque for glass-frit-sealed packages

For lid torque testing, MIL-STD 883 Method 2024.2 applies. Click here to go there.

We have converted the method into a readable HTML format, just like MIL-STD-883 method 2004.7 here.

Die shear

Die shear on LTCC
Die shear on LTCC

Die shear strength is the subject of MIL-STD-883 Method 2019.9. We also have a page on the test type, laying out the unique characteristics of XYZTEC's bond testers in relation to die shear.

Stud pull

The stud pull test is based on the principle that an adhesive connection is made with the carrier (or object to be tested) by using a glue that is stronger than the bond that needs to be tested. For flip-chip pull-off tests MIL-STD-883 method 2031.1 applies.

Wire Pull

www.wirepull.how

Click here if you wish to learn everything there is to know about Wire Pull. The extensive how-to on Wire Pull consists of 12 paragraphs, 7 pages and 4 appendices.

Cold Bump Pull

www.coldbumppull.how

Click here if you wish to learn everything there is to know about Cold Bump Pull (CBP). The extensive how-to on CBP consists of 12 paragraphs and 7 pages.


Test types

How to test bonds?

Lead integrity

All XYZTEC bond testers can be used for lead integrity testing. The MIL standard on this page describes the procedure in technical language. Our lead integrity test type page illustrates the test conditions A, B1, B2, C1, C2 and D with real examples. Click here to go there.

MIL-STD-883 method 2004.7 consists of 9 pages:

  1. Lead integrity
  2. A - Tension
  3. A1 - Lead braze integrity
  4. B1 - Bending stress
  5. B2 - Lead fatigue
  6. C1 - Lead torque
  7. C2 - Stud torque
  8. D - Solder pad adhesion for leadless chip carrier and similar devices
  9. E - Lead plating integrity

Lid torque for glass-frit-sealed packages

For lid torque testing, MIL-STD 883 Method 2024.2 applies. Click here to go there.

We have converted the method into a readable HTML format, just like MIL-STD-883 method 2004.7 here.

Die shear

Die shear on LTCC
Die shear on LTCC

Die shear strength is the subject of MIL-STD-883 Method 2019.9. We also have a page on the test type, laying out the unique characteristics of XYZTEC's bond testers in relation to die shear.

Stud pull

The stud pull test is based on the principle that an adhesive connection is made with the carrier (or object to be tested) by using a glue that is stronger than the bond that needs to be tested. For flip-chip pull-off tests MIL-STD-883 method 2031.1 applies.

Wire Pull

www.wirepull.how

Click here if you wish to learn everything there is to know about Wire Pull. The extensive how-to on Wire Pull consists of 12 paragraphs, 7 pages and 4 appendices.

Cold Bump Pull

www.coldbumppull.how

Click here if you wish to learn everything there is to know about Cold Bump Pull (CBP). The extensive how-to on CBP consists of 12 paragraphs and 7 pages.


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