Challenges with 01005 Components

• Pad design on the board — associated defects: tombstoning, unsoldered parts
• Stencil design and thickness — paste deposition issues. The population on the boards is also very important — the 01005s in combination with large components on the same board may require stepped stencils
• Paste selection in combination with stencil — a type IV paste in combination with a nano-coated stencil has shown good results for deposition and paste release from the stencils — apertures
• Paste deposition inspection — not enough as well as unbalanced volume can lead towards tombstoning
• Pick and place repeatability, component placement pressure,total assembly time — placement position (x,y) is critical as well as the placement pressure (the component being "in the paste"). Long assembly time will "dry" your paste
• Reflow profile — aggressive profiles will increase the tombstoning problems
• Do not forget to have available tools for rework if necessary — hand soldering tool tips are available for components that small — have them available just in case.

• ASSEMBLY PROCESS CHALLENGES FOR 01005 COMPONENTS Authors: Rita Mohanty and Vatsal Shah Date:08/17/2008
  Conference: SMTA International (SMTA International Conference Proceedings)
• 01005 Assembly Process, Materials and Tooling
  Denis Barbini, Universal Instruments Corp
  http://www.smta.org/chapters/files/Oregon_Barbini_SMTA_01005.pdf.

1. Printing a sufficient volume of solder paste and having sufficient paste pad coverage are critical both to the placement process and for proper solder joint formation.
2. A positional placement accuracy of 0.002 in. is the placement accuracy neighborhood needed for low ppm defect rates.
3. A 0.002 in. thick electro-formed stencil provided good results with either type 3 or type 4 paste sphere size.
4. A 0.004 in. thick laser cut stencil provided acceptable results only with paste made with type 4 powder.
5. Rapid heating during reflow is important to prevent solder sphere oxidation. An oven profile that results in a straight, rapid temperature ramp rate of close to 3.0 deg. C per sec. was found to yield good reflow soldering characteristics.
6. Reflowing in an inert environment (< 10 ppm O2) would widen the reflow process window.
   
   Source:"Process Characterization of the 01005 (English) Component Package"
   Tom Borkes, The Jefferson Project, Orlando, FL
   Lawrence Groves, Dynatech Samsung, Horsham, PA


Santosh Kumar
R&D Manager
MK Electron Co. Ltd

Santosh Kumar is R&D Manager at the MK Electron Co. Ltd., Korea and engaged in the electronic interconnect materials development and technical marketing. His key focus is novel lead-free solder materials, electronics packaging, wire bonding materials and process.

You may wish to consider an ionizer set-up for the pick/place machine. It helps to reduce the static buildup from the tape and reel packaging. Without it even very minor static charges can cause the small parts to jump out of the tape cavities as the cover tape is peeled back, making repeatable pick performance nearly impossible. Many think that the issue is sticky cover tape but that is not usually the case. The ionizer should not blow directly onto the open reels, but rather indirectly over the feeders. I have seen this make a huge improvement in pick and place performance for many companies.

Richard D. Stadem
Advanced Engineer/Scientist
General Dynamics

Richard D. Stadem is an advanced engineer/scientist for General Dynamics and is also a consulting engineer for other companies. He has 38 years of engineering experience having worked for Honeywell, ADC, Pemstar (now Benchmark), Analog Technologies, and General Dynamics.