H. Richter, K. Ruess, A. Gemmler and W. Leonhard
Bumping is a prerequisite forflip‐chip attachment of bare dies. For silicon semiconductors bumping is normally performedon the ICs at wafer scale. Bumping can be performed by…
Abstract
Bumping is a prerequisite for flip‐chip attachment of bare dies. For silicon semiconductors bumping is normally performed on the ICs at wafer scale. Bumping can be performed by micro‐plating or vacuum deposition techniques. Mechanical methods are also well known. In this paper a bumping process based on tin/lead alloy plating is reported. The plating bath presented enables the deposition of both solder compositions used for flip‐chip attachment, the eutectic and the lead‐rich. All key issues of the plating process covering plating equipment, electrolyte characteristics and plating process parameters are discussed. Methods of bump characterisation and quality assurance are reported as an important part of the bumping process. The deciding process parameters leading to high quality solder bumps are demonstrated.
Fan Zeng, Beshah Ayalew and Mohammed Omar
The purpose of this paper is to present a new closed‐loop radiative robotic paint curing process that could replace less efficient and bulky convection‐based paint curing…
Abstract
Purpose
The purpose of this paper is to present a new closed‐loop radiative robotic paint curing process that could replace less efficient and bulky convection‐based paint curing processes in automotive manufacturing.
Design/methodology/approach
The proposed robotic paint curing processes uses an Ultraviolet LED panel for a heat source, an infra‐red camera for non‐contact thermal signature feedback of cure level, and a robot control strategy that incorporates the cure‐level information in an inverse dynamics control of the robotic manipulator. To demonstrate the advantage of the closed‐loop process in improving cure uniformity, detailed models and discussions of the irradiation process, the robotics and the control strategy are presented.
Findings
A simulation‐based comparison of the closed‐loop robotic curing with the open‐loop robotic curing clearly shows the benefits of using thermal signature feedback in improving cure level uniformity.
Originality/value
This is a new approach proposed to exploit immerging technology and improve the efficiency of energy use in an automotive manufacturing process without sacrificing product quality.