9.1.1 BGA Component Rework Process Flow

Outline

This procedure covers BGA component rework process flow instructions.

Minimum Skill Level - Advanced

Conformance Level - High

Procedure

Introduction
Circuit Technology Center, Inc. has prepared this document. The purpose is to ensure repeatable, high-quality rework of BGA components and to assure conformity to the highest industry standards and specifications.

Note: This document covers procedures and guidelines specific to BGA component rework conducted by the staff at Circuit Technology Center, Inc. Organizations using this information may need to make modifications or other changes to accommodate their own particular needs.

Initial Processing

1. Receiving and Price Quoting
   Upon arrival, the Circuit Technology Center Sales Department will review each BGA component rework project. Personnel will refer to BGA Rework Process Worksheets when evaluating potential BGA rework projects. Only appropriate scheduling personnel are authorized to schedule the completion date.
2. Repeat Projects
   If the BGA component appears to have been processed before, it should be checked in the BGA Rework Process Worksheets. An appropriate scheduling adjustment may be required if the BGA component requires reballing or if the BGA component site requires modification or repair. Sales Department personnel will inform the Production Manager about any complexities to ensure appropriate scheduling.
3. New Projects
   The circuit boards and BGA components must be evaluated for all new projects according to the BGA Rework Process Worksheet. New BGA component rework projects require the following items to develop a proper rework profile.
   (1) Assembled profile circuit board.
   (2) Profile components for each BGA component rework location.
   Note: Customers must be made aware of the necessity of these profile boards and components. In most cases, it will be impossible to proceed without these items. If these items are unavailable, BGA rework projects must be reviewed case-by-case.
4. Profiling
   Much of our current profiling is done using the AirVac Smart Trac System. This profiling system eliminates the necessity of drilling into the board substrate to collect temperature data. However, one to three reflow cycles will be needed to determine the proper profile of the component location.
   Note: When an appropriate profile circuit board is not available, the actual circuit board may be exposed to multiple reflow cycles to determine the proper reflow cycle. These multiple reflow cycles may degrade overall reliability.
5. BGA Process Worksheets
   Please complete the required information. If you are unsure whether the board has been worked on previously, see the past BGA Process Worksheet. If all items are present, work with the appropriate scheduling authority to schedule a date. If any items are missing, discuss the shortage with the Sales Department and notify the customer if needed. Once the BGA rework project has been quoted, it should be forwarded to Customer Service for order entry and customer approval. If there are any outstanding issues, including ordering stencils, nozzles, or reballing, ensure that the BGA Rework Department is notified as soon as the order is approved. Note: When coding BGA projects, use only the approved codes.
6. BGA Rework Process Worksheets
   The continual changing of board/component part numbers makes it difficult to determine whether a particular circuit board and component location was previously reworked. Refer to the BGA Process Worksheet before beginning each repeat project.

Staging/Preparation

1. Staging
   After each BGA rework project has been logged and quoted, it will be staged as follows:
   Small Orders - Deliver directly to the BGA rework area with appropriate labels. Loose boards with parts will be loaded into racks marked "Incoming." Small boxes with parts will be brought to the rack marked "Incoming Boxes."
   Large Orders - Deliver to the incoming holding area for staging.
2. Initial Inspection
   When starting a new BGA rework project, personnel should consider the following:
   1. Verify circuit board and component part numbers and quantities against the customer packing slip and Circuit Technology Center sales order.
   2. Determine the correct nozzle, stencil, and rework profile.
   3. Ensure the circuit board will fit on the base of the BGA rework machine. Over-sized boards may require special handling.
   4. Visually inspect circuit boards for temperature-sensitive components or parts. (Fiber optics, plastic connectors, batteries, etc.)
   5. Review the BGA Machine Preventive Maintenance Schedule. Ensure the appropriate checks are done before operating BGA rework machines.
3. BGA Component Handling
   When starting a new BGA rework project, personnel should consider the following:
   BGA components may be sensitive to moisture. If BGA parts are not received in sealed packages, those BGA parts must be baked as follows:
   1. Remove BGA components from packaging.
   2. Place BGA components into a labeled tray. The tray must be labeled with Customer Name, Sales Order No., and Baking Start Time/Date.
   3. Bake BGA components at 125 °C for 24 hours.
   4. After baking, allow parts to cool to room temperature and immediately place them into sealed moisture barrier bags. Bags must be labeled with the Customer Name and Sales Order number. Bags must be placed into a desiccant chamber.

BGA Component Rework Processing

1. Initial Review/Disassembly
   Operators should initially review all paperwork. Assess circuit boards to determine the need for any disassembly or component masking. If disassembly is needed, all materials must be labeled, and instructions must be written to ensure that materials are replaced after rework.
2. BGA Machine Inspection
   The following should be checked before starting:
   1. Appropriate Nozzle Installed
   2. Rework Profile Available
   3. Proper Input Air Pressure
      Note: If this is the first piece in a larger order, it may require a formal First Piece Inspection. See the Production Manager or Inspection for guidance.
   4. Reflow Profile - Existing
      Use the designated reflow profile if available. If the reflow profile is not available on the particular BGA rework machine, the profile may be transferred from another machine.
   5. Reflow Profile - Creation
      Each unique rework profile includes a removal, placement, and site cleaning cycle. Refer to the following procedures for details: 9.2.1 BGA Component Rework Profile Development, Standard Method; 9.2.2 BGA Component Rework Profile Development, Smart Track Method.
      If no profile is available, an existing profile that closely matches the component and board size may be used. All parties must be aware of the inherent risk in using common profiles.

Images

BGA Component Rework Process Flow

Process flow steps.