IPC-TM-650 EN 2022 试验方法.pdf - 第691页

1 Scope and Purpose 1.1 Scope This method subjects unpopulated test speci- mens (samples) to sudden, extreme changes in temperature in order to evaluate the quality of interconnects formed during the manufacturing proces…

Scope

This

test method is to determine the physical

endurance of applied conformal coating to sudden changes of

high and low temperature excursions that cause physical

fatigue.

Applicable Documents

IPC-CC-830

Qualification

and Performance of Electrical Insu-

lating Compound for Printed Board Assemblies

Test Specimens

Five

IPC-B-25A boards (see Figure 1)

coated with conformal coating per coating supplier’s recom-

mendations.

Apparatus

Test

chamber - automatically controlled dual

temperature environmental test equipment or two separate

chambers capable of maintaining -65° ± 5°C [-85° ± 9°F] and

250° ± 5°C [482° ± 9°F] respectively. Please note, while most

requests state 125° ± 5°C [257° ± 9°F] on the high side, there

are cases (such as polyimide board applications) where a

higher temperature will be required. Test conditions, if not

otherwise stated as below, shall be -65°C [-85°F] and 125°C

[257°F].

Class

Low Temperature High Temperature

N/A N/A

2 -40°C [-40°F] 125°C [257°F]

3 -65°C [-85°F] 125°C [257°F]

4 -65°C [-85°F] 250°C [482°F]

5 Procedure

5.1 Specimen Preparation

Operate

the chamber(s) to

high and low temperatures and stabilize. Clamp or suspend

the five conformal coated IPC-B-25A boards in the thermal

shock chamber.

5.1.1 Set

the cold portion of chamber at -65°C [-85°F] and

the hot portion of chamber at 125°C [257°F].

5.1.2

Set

the dwell time for 15 minutes.

5.1.3

Set

the temperature recovery time for less than two

minutes.

5.1.4

Set

the chamber for 100 cycles.

5.1.5

Activate

the test chamber and begin testing.

5.2

Evaluation

5.2.1

Upon

completion of the thermal shock test, the speci-

mens shall meet the requirements of appearance and dielec-

tric withstanding voltage in accordance with IPC-CC-830.

IPC-2671-1

Figure

1 IPC-B-25A Test Board

2215

Sanders Road

Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.6.7.1

(Supersedes

2.6.7.1 for Conformal Coating Tests)

Subject

Thermal Shock - Conformal Coating

Date

07/00

Revision

Originating Task Group

Conformal Coating Task Group (5-33a)

Material

in this Test Methods Manual was voluntarily established by Technical Committees of IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.

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TION CONNECTING

ELECTRONICS INDUSTRIES

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1 Scope and Purpose

1.1 Scope

This method subjects unpopulated test speci-

mens (samples) to sudden, extreme changes in temperature

in order to evaluate the quality of interconnects formed during

the manufacturing processes.

1.2 Purpose This method shall be used to simulate the

thermodynamic effects of extreme temperature variations. The

use of this method is intended to be able to capture ‘‘infant

mortality’’ types of manufacturing defects.

1.2.1 This method may provide for qualification, quality con-

formance testing and lot acceptance.

2 Applicable Documents

IPC-T-50

Terms and Definitions

IPC-2221 Generic Standard on Printed Board Design

IPC-A-600 Acceptability of Printed Boards

IPC-1601 Standard for Printed Board Handling and Storage

IPC-4101 Specification for Base Materials for Rigid and Mul-

tilayer Printed Boards

IPC-4103 Specification for Base Materials for High Speed/

High Frequency Applications

IPC-6012 Qualification and Performance Specification for

Rigid Printed Boards

IPC-6013 Qualification and Performance Specification for

Flexible Printed Boards

IPC-6018 Qualification and Performance Specification for

High Frequency (Microwave) Printed Boards

IPC-9241 Guidelines for Microsection Preparation

IPC-TM-650 Test Methods Manual

2.1.1 Microsectioning - Microsectioning, Manual and Semi

or Automatic Method

2.6.27 Assembly Simulation - Thermal Stress, Convection

Reflow Assembly Simulation

3 Terms and Definitions

3.1 Thermal Shock (Unpopulated Printed Board)

A tem-

perature cycle with a change rate of 1 °C or more per second

as measured on the surface of the test specimen, for at least

the center 60% of each transition, during the heating and

cooling portions.

3.2 Thermal Cycle (Unpopulated Printed Board) A tem-

perature cycle that has a sample change rate of less than 1 °C

per second as measured on the surface of the test specimen,

for at least the center 60% of each transition, during the heat-

ing and cooling portions. While no minimum temperature

change rate is specified, a change rate of at least 10 °C per

minute is expected for qualification testing.

4 Test Specimen

4.1 Design/Construction Criteria

4.1.1

The test specimen shall be the D coupon in accor-

dance with the requirements of IPC-2221 Appendix A, or

alternate coupon(s) AABUS.

4.1.2 The test specimen(s) shall be constructed with holes

contained in the printed board it represents as follows:

• Through holes: D coupons shall be constructed with both

the largest plated-through holes (PTHs) and the smallest

plated-through vias.

• Propagated structures: D coupons shall be constructed

with and represent all applicable blind, buried, or filled

through hole (propagated) via structures as defined in IPC-

2221 Appendix A. D coupons contain two nets (structures).

Multiple D coupons are used for designs with more than two

structures.

4.1.2.1 The test specimen(s) shall contain the representa-

tive ground and power planes of the printed board design.

4.1.3 The test specimen(s) shall allow for microsection

evaluation of all the applicable, representative PTHs and vias

defined in 4.1.2 after exposure to the conditions of this Test

Method. IPC-9241 provides guidance on the proper prepara-

tion of a metallographic sample (microsection) of a printed

board.

3000 Lakeside Drive, Suite 105N

Bannockburn, IL 60015-1249

IPC-TM-650

TEST METHODS MANUAL

Number

2.6.7.2

Subject

Thermal Shock, Thermal Cycle and Continuity

Date

3/2020

Revision

Originating Task Group

Thermal Stress Test Methodology Subcommittee

(D-32)

Material in this Test Methods Manual was voluntarily established by Technical Committees of IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.

Page1of5

4.1.4 Deviations to the test specimen design/construction

or use of an alternate test specimen shall be AABUS.

5 Apparatus

5.1 Drying Oven

The oven shall be capable of maintaining

a uniform set temperature within the 105 to 125 °C range.

5.2 Environmental Test Chamber

5.2.1 Dual Chamber Option An automatically controlled

dual temperature environmental test chamber or other

apparatus capable of maintaining the upper and lower

temperatures.

5.2.2 Single Chamber Option An automatically controlled

environmental test chamber or other apparatus capable of

maintaining the upper and lower temperatures.

5.2.3 The system shall have adequate environmental con-

trols to maintain the tolerance range and limits listed in

6.5.1.3.

5.2.4 The system should accommodate verifiable calibration

compliance. See note 7.1 for additional considerations.

5.2.5 Deviations to the equipment requirements and

acceptability of the alternative methods shall be AABUS.

5.3 Microscope The magnification used for defect recogni-

tion shall be in agreement with the inspection requirements/

capabilities defined in the applicable performance specifica-

tion (e.g., IPC-6012, IPC-6013, IPC-6018, etc.) and the IPC-

A-600 visual workmanship standard.

5.4 Resistance Measurements

5.4.1

The resistance measurement shall have enough pre-

cision to clearly determine the resistance percent change as

required by the user for the resistance level of each test speci-

men’s nets.

5.4.2 The total system uncertainty from resistance, tem-

perature and time/cycle variations shall be less than 10% of

the failure criteria required by the user. For example, if the

required failure criteria is 5% then the total system uncertainty

shall be no greater than 0.50%.

5.4.3 The resistance measurement system shall be capable

of recording resistances at least once per cycle, at or near the

end of the peak temperature dwell, after the coupon has

reached temperature stabilization.

5.5 Temperature Measurements

5.5.1

The temperature measurement system should be

capable of recording temperatures at least once per second

throughout a complete cycle for both a representative test

specimen and the heating/cooling medium. The system shall

be capable of demonstrating the change rate defined in 3.1

and 3.2 and documenting a representative cycle.

6 Procedure

6.1 Conditioning

6.1.1

The test specimen(s) shall be conditioned by drying in

an oven to remove moisture for a minimum of six (6) hours at

105 to 125 °C. This conditioning process is mandatory if this

method is used for qualification purposes.

This method shall replicate the assembly process. The

requirement for conditioning (bake/drying) shall be in accor-

dance with product/process lot Quality Conformance criteria.

If conditioning of the printed board is not part of the normal

assembly process, and this method is being used for quality

conformance testing, then conditioning is not a requirement.

6.1.2 Test specimens that are thicker or more complex may

require longer baking times to achieve acceptable moisture

levels. Record the bake times and temperature if different than

those stated in 6.1.1. See IPC-1602 for additional guidance

on baking to achieve acceptable moisture levels.

6.1.3 Deviations to the conditioning requirements in 6.1.1

such as when used for quality conformance criteria and/or any

changes to the time and temperature shall be AABUS.

6.2 Reflow Simulation

6.2.1

The test specimen(s) shall be subjected to six (6)

reflow simulation cycles in accordance with IPC-TM-650,

Method 2.6.27 prior to Thermal Shock or Thermal Cycling.

6.2.2 The reflow profile shall be in accordance with IPC-

TM-650, Method 2.6.27, as specified.

6.2.3 Other profiles or reflow simulation testing for other

than 6 cycles are AABUS.

6.3 Interconnect Resistance Measurements Intercon-

nect resistance measurements shall be taken at the following

times:

• Prior to the test (initial ambient after reflow simulation).

IPC-TM-650

Number

2.6.7.2

Subject

Thermal Shock, Thermal Cycle and Continuity

Date

3/2020

Revision

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