Why Use An Assembly Design Kit And Assembly Design Flow?

Complex packages make it necessary to handle data in a machine-readable format.


A number of years ago, the packages of electronic systems were only intended to protect the circuit from mechanical stresses and to realize a simple fan-out from the close spacing of connections on the circuit to the larger spacing on the packaging. At the time, there were also only a few different packaging types, all of simple design. Over the years, however, the requirements on packages have increased considerably, for instance due to the extreme growth in the number of connections to the circuit. These developments have led to the integration of complex systems for wiring management and fanning out the connections. This generally also includes a substrate that is now realized in the smallest achievable interconnect dimensions. The embedding of multiple circuits has also given rise to new packaging requirements.

As a result, an entire spectrum of new and sometimes highly complex packages has been developed in recent years. This concerns above all the fan-in and fan-out packaging types, interposers and packages for multi-chip integration.

The rise in requirements has also been driven by the applications. In particular, the maximum frequencies to be realized have grown ever higher. These are driven primarily by applications in the area of mobile communication, data transmission at the highest rates and also by radar sensors for automobiles.

This poses new challenges for both system engineers and designers with regard to the introduction of new packaging types into their products. In general, these tend to be introduced with great hesitation because there are many risks involved and little (detailed) knowledge of the packages.

This makes it increasingly important for the system engineers to be able to compare different packages at an early stage in order to select the best solution for the given task based on various aspects. Both the performance and the price represent key values to be targeted and optimized here. After comparing a number of variants, the system engineer can decide on a specific package.

With this decision, the package designer can begin his design work. A great many different requirements must also be met in this process. For example, there are a variety of requirements that apply to electrical performance characteristics. Interconnects for special high-speed signals have different requirements than interconnects for power/ground networks, for instance.

For both the system engineer and the package designer, it is important that the data on the packaging design is available in simple, compact form. Only if the data is available in machine-readable format can various software programs be used for design, verification and fast exploration of different variants. Implementation in assembly design kits (ADK) is ideal to provide such data. An ADK is a way to prepare the packaging data similar to the process design kit (PDK), which has been long established in the chip industry. This allows packaging data to be made available in a standardized way for various software programs, including information typically used in the chip industry, such as design rules (interconnect spacing, line width, etc.) as well as material data on electrical performance, for example.

To effectively use the ADKs in various software programs for circuit design, verification and other purposes, they must be integrated into a standardized flow. This also includes a shared data basis for managing the design data to allow access by various tools. This end-to-end flow is provided in an assembly design flow (ADF) that enables access, reading and modification of the data by various software tools (e.g. for design, verification, etc.). The corresponding software can even originate from different manufacturers.

This gives the system engineer the ability to use the ADKs of various packaging types (including from different manufacturers) and to quickly explore different packaging variants with his software tool. As a result, it is possible to efficiently compare different package variants for the given application without special or detailed knowledge as well as to introduce new packaging types into products with an acceptable level of risk.

There are also significant advantages for the package designer. For example, he can be certain that a package is suitable for manufacturing if all design rules specified in the ADK have been complied with. This also reduces the risk of errors in connection with the specific implementation.

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