Developing a new IC involves more than designing and fabricating the die. At some point, the device needs to be assembled into a package so engineers can begin electrical testing, characterization, and system-level evaluation.
For early-stage prototypes, time can become a packaging constraint of its own. Waiting for new package tooling, sourcing small quantities, or coordinating a custom package build can delay the point at which engineers can begin testing the device.
Open-Cavity Plastic Packages (OCPP) provide a practical approach to shortening that path. By modifying an existing plastic IC package, engineers can move from available die to packaged prototype without waiting for new transfer-mold tooling.
What Is an Open-Cavity Plastic Package?
An Open-Cavity Plastic Package starts with an existing plastic IC package, with or without a die inside. The package is reconfigured to create an open cavity, removing any existing die and providing access to the area where the die can be assembled.
This allows a new die to be assembled into a package that is representative of the intended production package. OCPPs replicate the mechanical structure and electrical characteristics of transfer-molded production packages.
The process can use customer-supplied packages or packages procured for the project. Existing packages can include dummy packages, electrical test rejects, or excess inventory that might otherwise have limited use.
The result is a way to create prototype packages without first developing an entirely new production package.
Why Time Matters in IC Prototyping
In semiconductor development, getting a packaged device into the lab is an important milestone.
Until the die is packaged, engineers may be limited in the types of electrical, thermal, mechanical, and system-level testing they can perform. A delay at the packaging stage can therefore push back characterization and design verification.
This is where OCPP can provide an advantage.
Rather than waiting for a new package design to be tooled and manufactured, an existing plastic package can be prepared for prototype assembly. This can reduce one of the potential bottlenecks between wafer or die availability and packaged-device testing.
Prepared OCPPs can be assembled in as little as eight hours once the die is ready for assembly.
For development teams working against tight schedules, that turnaround can be particularly relevant.
The value is not simply that the assembly itself can be completed quickly. It is the opportunity to start testing sooner.
Avoiding New Package Tooling During Development
Prototype programs often begin before all production decisions have been finalized.
A development team may know which plastic package it intends to use but may not yet be ready to invest in dedicated production tooling. For a small prototype quantity, creating new tooling may also add time and cost that are difficult to justify.
OCPP provides another option.
An existing plastic package can be modified for prototype assembly without requiring new transfer-mold tooling. This makes it possible to begin building and evaluating devices while longer-term production packaging plans continue to develop.
This can be useful when:
- Prototype quantities are limited
- Production package tooling is not yet available
- A specific package is difficult to source in small quantities
- The development schedule is compressed
- Engineers need to begin testing as soon as the die is available
In other words, OCPP can help remove packaging from the critical path during an early stage of development.
Working With Existing Package Inventory
Another advantage of OCPP is that the starting package does not necessarily have to be newly manufactured.
QP Technologies can work with existing plastic packages, including customer-supplied packages, dummy packages, electrical test rejects, and excess inventory. Suitable packages can be converted into open-cavity configurations for assembly.
This can be especially useful when a development team already has the package it plans to use but does not have enough production-ready packages available for prototyping.
Packages can also be prepared in advance and stored until the wafer or die is ready for assembly.
That creates another opportunity to save time: package preparation does not necessarily have to wait for the die.
When the semiconductor material becomes available, the prepared packages are already further along in the assembly process.
Supporting a Range of Package Configurations
OCPP is not limited to a single package style.
Our process can accommodate a range of package sizes and lead counts, including BGA, DIP, QFN/DFN, PLCC, QFP, SOIC, SOT, TO and other common plastic package configurations.
This flexibility matters because package requirements vary from one device to another.
The prototype may need to fit an existing board layout, socket, test fixture, or system architecture. Starting with the package configuration intended for production can help engineers evaluate the device without introducing unnecessary differences into the prototype.
From Open Cavity to Packaged Device
Once the die is ready, it can be assembled into the prepared OCPP using the appropriate assembly process.
Depending on the application, the cavity can be closed using an epoxy-sealed lid, filled with glob-top material, or covered with a taped-on lid. The taped-on lid option can provide access when the die or cavity needs to be inspected after assembly.
The appropriate approach depends on what the prototype needs to accomplish.
For a device moving directly into testing, a more permanent configuration may be appropriate. For development work where engineers may need continued access to the cavity, a removable approach may provide greater flexibility.
The packaging method can therefore be selected around the needs of the development program rather than forcing every prototype into the same configuration.
Faster Access to Design Verification
The purpose of prototype packaging is ultimately to give engineers a device they can test.
That distinction is important.
The benefit of a faster packaging process is not simply a shorter manufacturing cycle. It is the time gained on the engineering side.
Earlier access to packaged devices can allow teams to begin electrical characterization, evaluate system integration, identify design issues, and make decisions while there is still time to incorporate changes into the development program.
Using a package representative of the intended production configuration can also make those results more relevant to the next stage of the program.
For development teams working toward a production package, OCPP can therefore serve as a bridge between the die and the final manufacturing process.
When Does OCPP Make Sense?
OCPP is particularly useful when the development team needs packaged devices quickly.
It may be worth considering when:
The die is ready before production packaging is ready.
OCPP can provide a way to move forward with assembly and testing rather than waiting for production tooling.
Only a small number of devices are needed.
A limited prototype build may not justify new package tooling.
Existing packages are available.
Excess inventory, dummy packages, or other suitable packages may provide a starting point for the prototype.
The production package is already defined.
Using the same package platform can provide a more representative prototype.
Testing needs to begin quickly.
When development schedules are compressed, reducing the time between die availability and packaged-device testing can be valuable.
The production package can’t be sourced onshore.
When ITAR or supply constraints rule out offshore assembly, OCPP can be qualified as a production solution.
From Prototype to Production
OCPP can provide a practical step during development while production plans are being finalized.
Once a design is validated, the program can transition to its intended production packaging process, or the OCPP solution itself can be qualified for production.
For some programs, however, the biggest challenge is getting through the prototype stage quickly enough to make those production decisions.
That is where open-cavity packaging can play an important role.
By preparing an existing plastic package for die assembly, OCPP can reduce the time and tooling requirements associated with early prototype builds while maintaining the package characteristics needed for meaningful evaluation.
The Value of Time in Semiconductor Packaging
In IC development, every stage of the process affects the next. A delay in packaging can become a delay in testing, and a delay in testing can push back design decisions and the overall development schedule.
Open-Cavity Plastic Packages provide a way to address that challenge.
By using existing plastic packages, avoiding new transfer-mold tooling during early development, and supporting rapid assembly once the die is available, OCPP can help shorten the path from die to packaged device to design verification.
QP Technologies combines OCPP with other IC assembly capabilities, including die attach, wire bonding, flip chip, encapsulation, and wafer preparation, supporting quick turn prototype and production development programs.
For semiconductor teams working under tight development schedules, the question is often not simply how to package a prototype, it’s how quickly that prototype device can get into the hands of the engineers who need to test it.
Learn more about Open-Cavity Plastic Packages and QP Technologies’ IC assembly capabilities.