Medical Device Assembly Using Jet Dispensing For Underfill Applications
•White Paper: Medical Device Assembly Using Jet Dispensing For Underfill Applications
Medical devices that have to be implanted in humans need to be made as small as possible to avoid discomfort to the user. At the same time new features and functions are being added to the design of implantable devices, and this puts tremendous pressure on the use of substrate area on these types of systems. To improve board utilization Plexus investigated the use of jet dispensing technology to dispense underfills for medical devices.
The underfill process is now common practice in the second level assembly process of flip chip and CSP devices. Medical devices that use these types of area array components have common problems. The use of a large variety of device types and the limited real estate that underfill materials can be applied causes iterative development. Figure 1 shows the variety of device types that can be encountered on a single assembly.
In a number of applications, underfill materials are not allowed to contact die surfaces, adjacent wire bonds or components. This has put severe pressure on dispensing companies to develop techniques for putting down small fillets of underfill or encapsulants in a controlled manner.
To get a precision movement of a dispensing needle tip usually involves slowing the dispensing system down, so small needles can maneuver into position and dispense in tight spaces, reducing throughput times. Additional there are limits to how small a needle can be used. Jet dispensing overcomes these barriers to enable assembly designers to obtain compact designs.
The goal of this paper is twofold. It will describe the work done to develop a jet capable of dispensing underfill materials, to produce smaller fillets for underfill and controlled encapsulant dispensing. Secondly, an example of how jetting was used in the assembly of medical devices to enable efficient manufacturing of difficult assemblies.
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•White Paper: Medical Device Assembly Using Jet Dispensing For Underfill Applications