KNOWLEDGE CENTER

PAPERS & ARTICLES

Flux Removal Method for Reflow Furnaces (477.6 KB)

SMTAI - 2020 - Described in this work, is a novel method of capture which separates flux from the recirculating furnace gas using an aqueous gas/liquid sequestration process. This system operates automatically and does not require production line shut-down for routine maintenance which consists of periodically emptying a small liquid waste container. This method is compatible with both Clean and No-Clean type fluxes. Capture efficiency of different fluxes were tested and will be reported in this study.

SMT REFLOW OVEN-TO-OVEN REPEATABILITY (644.7 KB)

In this article Fred Dimock, BTU’s Manager Process Technology, explains oven-to-oven repeatability across multiple SMT reflow oven process lines using a single process recipe.

Reducing CTE Mismatch Defects in Flip Chip Reflow (418.9 KB)

US Tech - May 2019 - In this article Thomas Tong and co-authors explain the use of the TrueFlat reflow oven technology to keep very thin substrates flat during reflow. This is an important consideration for flip chip processes where CTE mismatch is an inherent process challenge.

Operation of a Vacuum Reflow Oven (1.2 MB)

In this presentation BTU's Fred Dimock explains the operation and configuration of an inline vacuum reflow oven. Included in this presentation is the preliminary voiding data generated when the Pyramax Vacuum reflow oven was at Universal's Advanced Process lab.

Thermal Processing Expertise Reaches Across Industry Boundaries (296.6 KB)

USTech - July 2018 - Michael Skinner of USTech visted BTU's USA Headquarters, where custom belt furnaces have been manufactured for nearly 70 years. The article covers BTU's capabilities for high temperature, controlled atmosphere processing as well as BTU's history in the reflow oven industry.

Maintaining Oven Performance while Reducing the Cost of Reflow ()

Electronics Production World - January 2015 - Fred Dimock discusses strategies to reduce energy and gas usage by taking advantage of system idle time. A software tool called, Energy Pilot, automates the process while ensuring product yield.

Reducing Reflow Costs in a Challenging Economy (1,006.7 KB)

Presented at SMTA San Diego - Sept 2013 -- In this presentation, Fred Dimock, Manager Process Technology, discusses 10 methods that can be used to reduce the cost of operating a reflow oven

Microwave Atmospheric Pressure Plasma for Surface Treatment and Reactive Coating on Steel Surfaces (2.6 MB)

Presented in Surface and Coatings Technology - 2006 - Demonstration on the use of atmospheric plasma assisted chemical vapor deposition (APACVD) process to coat steel surfaces.

Hybrid Microwave Drying of “Water Based” Electrode Slurries (555.0 KB)

Presented at 6th International Conference on Advanced Lithium Batters for Automobile Applications (ABAA6) - Sep 2013 -- Demonstration of drying of water based Cathode coatings used in Li battery processes. Fast, Uniform drying can be achieved in minutes, which could potentially save energy, foot print size and cost.

High Volume Powder Processing Via Thermal Treatment (98.8 KB)

Presented at 6th International Conference on Advanced Lithium Batteries for Automobile Applications (ABAA6) - Sep 2013 -- Presentation of a belt furnace with a capability to reach 1100°C and high degree of uniformity, which could be useful for chemical powder processing of battery materials.

SMT Reflow Oven-to-Oven Repeatability (11.7 MB)

Circuits Assembly Magazine - April 2013 - BTU's Fred Dimock discusses using CpK to measure oven repeatability. The article includes an overview of simple statistical concepts and how their application to SMT reflow.

Thermal Profiles – Why Getting Them Right is Important (806.2 KB)

Presented at ACI Technologies - Dec 2011 -- In this presentation, Fred Dimock, Manager Process Technology, gives a comprehensive overview of thermal profiling including: recipes vs. profiles, material properties, TC acccuracy, profilers and test vehicles, process window, heat transfer and oven control.

Mechanistic Study of Forming Gas Annealing of c-Si Solar Cell Electrodes (369.5 KB)

Solar Energy Materials & Solar Cells - July 2011 -- Forming gas annealing (FGA) is an effective process to repair low efficiency crystalline silicon (c-Si) solar cells with over-fired screen-printed paste electrodes.

Rapid Metallization Paste Firing of Crystalline Silicon Solar Cells (227.2 KB)

Presented at IEEE- June 2011 -- BTU's solar applications group report on a method of co-firing using very high ramp rates and rapid cooling. The study addresses the requirements for aluminum BSF formation.

Solar-Specific Strategies Are Distancing Diffusion From Semiconductor Past (886.7 KB)

Solar Industry Magazine - January 2011 --- BTU's vice president of marketing, Jan Paul van Maaren, discusses diffusion techniques including advancements with selective emitters. A variety of doping technologies are covered in the article.

Practical Thermal Profile Expectations in a Dual-Lane, Dual-Speed, Reflow Oven ()

Circuits Assembly - March 2011 --- Fred Dimock, BTU's Manager of Process Technology, gives practical insight into the development of thermal profiles/recipes for Dual Lane Dual Speed processing.

High-Ramp Industrial Firing Processes for the Metallization of Crystalline Silicon Solar Cells (139.8 KB)

Presented at IEEE - 2010 --- Rapid firing of screen-printed mtallization is a critical step in the manufacture of crystalline solar cells. In this paper BTU's solar applications engineers investigate the changes in the structure of fired contacts caused by variations in firing parameters.

PSG Trapping of Metal Contaminants During Belt Furnace Inline Phosphorus Diffusion in Crystalline Si Wafers (211.3 KB)

Presented at IEEE - 2010 --- There is growing interest in adopting in-line diffusion on an industrial scale. In this paper an old concern of metal contamination from conveyor belts is explored using SIMS analysis.

Diffusion Techniques, From Blue-Cell Theory To In-Fab Practice (133.4 KB)

Solar Industry - Mar 2010 --- The article provides an overview of in-line diffusion from BTU's chief solar scientist, Dr. David Wong

Solar Cell Process Temperature Measurements ()

Global Solar Tech Magazine - Jan 2010 --- Profiling techniques for a number of photovoltaic processes are discussed including metallization firing and in-line diffusion.

Oven Adjustment Effects on a Solder Reflow Profile (1.3 MB)

Circuits Assembly Magazine - Aug 2009 ---- This paper ivestigates the effects of variations on belt speed, static pressures, and zone temperatures on peak temperature, time above liquidus (TAL) and thermal uniformity.

Cost of ownership and overall equipment efficiency (211.3 KB)

Photovoltaics International - Nov 2009 --- A paper by David Jimenez of Wright Williams & Kelly, Inc., uses a standarized cost of ownership analysis to compare in-line diffusion with batch processing.

Wafer Level Packaging (2.9 MB)

SECAP - 2005 --- A collection of papers on wafer level packaging and flip chip bumping covering a range of topics including plating, UBM, photolithography, and lead-free processing. As a member of SECAP, BTU contributed a paper on Next Generation Wafer Bump Reflow Processing.

Maximizing Process Control with Controlled Convection Rates (792.8 KB)

Reprinted from Global SMT & Packaging Magazine - Jan 2004 --- The effects of convection rate on process repeatability, peak temperature and thermal uniformity are investigated.

Effect of High-Temperature Requirements for Lead-Free Solder (381.3 KB)

Circuits Assembly - July 2004 --- The transition to lead-free processing is discussed including the lead-free process impact and whether a new reflow oven is required.

SMT Magazine Step 7 Soldering (61.6 KB)

SMT Magazine - Aug 2004 --- Part of SMT Magazine's "step by step" series. The "Step 7" article covers soldering including a discussion on lead-free processing.

Lead Free Solder Wafer Bumping – Oven Control and Solder Material Consistency Are Critical (150.9 KB)

Advanced Packaging - Sept 2004 --- A discussion on the transition to lead-free processing for wafer bump reflow with a focus on process control.

Oven Selection and Lead-Free Solder (634.5 KB)

Global SMT & Packaging - Oct 2004 --- A discussion on the oven requirements for lead free solder. This article discusses issues like oven length, thermal capacity, speed, zones, flux management, board support mechanisms, the use of nitrogen, and convection control.

Wafer Bump Reflow: Benefits of a Flux-Free Atmosphere (118.9 KB)

Advanced Packaging Magazine - July 2003 --- The article discusses the benefits of relflowing bumped wafers in a reducing atmosphere.

Making A Case for Continuous Furnaces (112.4 KB)

Industrial Heating Magazine - Sept 2002 --- A continuous furnace is ideal for processes requiring high production volumes, process consistency,and precision control. This overview discusses some of the newer temperature and atmosphere capabilities of continuous furnaces and addresses the various components that make up a continuous furnace.

Improving Reflow wSPC Part I (227.3 KB)

Circuits Assembly - Dec 2001 --- First of a three-part series on using SPC to improve the reflow process. In this article analytical tools are used to determine how all oven parameters are operating at the time an optimum oven profile is established.

Improving Reflow wSPC Part II (1.0 MB)

Circuits Assembly - Jan 2002 --- This is the second article in the three-part seiries on using SPC in the reflow process. This article describes the types of SPC tools that can be used to better understand the relationship between processing steps and how SPC, properly implemented, can track quality, monitor process deviations and increase yields.

Improving Reflow w/SPC Part III (218.1 KB)

Circuits Assembly - Feb 2002 --- The final part of the three-part seires on using SPC to improve the reflow process.

Enhanced Atmosphere Separation and Closed Loop Oxygen Control for BME MLCC Sintering (67.5 KB)

Capacitor and Resistor Technology Symposium (CARTS) - Mar 2001 --- This paper discusses a new method available for achieving atmosphere convection, separation and closed loop Oxygen control in a BME MLCC Pusher Furnace.

Glass to Metal Sealing by a Single-Atmosphere, Single Firing Process (854.3 KB)

The International Journal for Hybrid Microelectronics - July 1988 --- A process is described whereby strong and hermetic matched seals can be fabricated in a single furnace pass.