scope:

SCOPE/INTRODUCTION

This Material and Process Characterization/Qualification Test records changes in Surface Insulation Resistance (SIR) on a representative sample of a printed circuit assembly (PCA). It quantifies any deleterious effects that might arise from solder flux or other process residues left on external surfaces after soldering, which can cause unwanted electro-chemical reactions that grossly affect reliability.

It uses test vehicles that are intended to be representative of the electronic circuits that are in production. It is a test yielding both quantitative and qualitative data.

This test may be used for Process Qualification, demonstrating that a proposed manufacturing process or process change can produce hardware with acceptable end-item performance related to electrochemical risk. Changes may involve any assembly process step, or a change in the printed board supplier, solder mask or metallization, soldering material supplier, conformal coating, etc. The test vehicle construction will vary depending upon the type of change being evaluated.

NOTE: The decision to levy this protocol on individual manufacturing sites shall be As Agreed Between User and Manufacturer. See IPC-9203 for further guidance (As of the publication of this document, IPC-9203 Rev A is under development. Contact the IPC for status and availability). Vehicles shall be prepared at the Manufacturer's location using production processes and equipment whenever possible. Care shall be taken to ensure that the processed test vehicles are kept free from any secondary contamination while in transit to the test site. Testing of the prepared vehicles can be performed by the User or at a suitable independent laboratory.

There is no single test that can guarantee acceptable electrochemical performance for all products, applications, and in-service environments. While there are several methods that may be used to determine materials and process compatibility, this test protocol may be used to generate objective evidence of electrochemical compatibility. IPC-J-STD-001 does not require testing to this specific method to qualify a manufacturing process.

It is strongly recommended that a subset of the unpopulated, unprocessed coupons be tested for SIR before investing the time and money to manufacture the test vehicles. If the unprocessed controls do not return acceptable SIR results because of some undiscovered fault in the design or construction of the vehicles, the populated PCAs are likely to fail also.

This test may also be used for Process Characterizations, including development of new processes or improvements to an existing process.

This test protocol is specific to the IPC-B-52 standard test assembly. The use of alternative test vehicles and associated pass-fail requirements shall be as agreed between User and Manufacturer.

The IPC-B-52 standard test assembly contains both surface mount and through-hole technologies. Only the applicable portions of the IPC-B-52 assembly are processed, i.e., only the surface mount patterns are processed for a surface mount only assembly process; however, all surface mount patterns shall be processed. For a process investigation, a User may elect to test as many or as few patterns as they desire.