Entegris Offers New FOUP Form-Factors for Non-Standard Wafers

Over the last few years, 3D stacking has gone from a relatively niche fabrication method to an absolute necessity for cutting-edge applications.  As chipmakers delve into smaller and smaller nodes, stacking and die-bonding wafers has become a preferred way of creating more processing power in a smaller space.

Stacked and bonded wafers don’t behave the same way as 2D wafers:

• Wafers are thinned prior to bonding, which results in wafers that can sag when handled
• Bonded wafers are thicker and heavier than 2D wafers when assembled
• Bonded wafers can also warp following assembly

Many automation tools rely on the predictable geometry and characteristics of 2D silicon wafers for safe handling and transport. While stacked and bonded wafers are a game-changer for miniaturization, they can also force manufacturing compromises unless chipmakers adopt specialized tools for the back end of the line (BEOL).

Non-Standard Wafers Force Improvised Solutions

Chipmakers have relied on standard front-opening unified pods (FOUPs) to transport standard wafers throughout BEOL. Non-standard wafers can challenge the capabilities of standard FOUPs, however.

• Thinned wafers sag, which means that they can potentially touch one another during transit. In addition, a sagging wafer is harder for automated handlers to position.
• Warped wafers are non-conformal, which means that there’s a smaller amount of lift clearance, making them harder for handlers to install.
• Stacked wafers are heavier. Under certain conditions, an emergency stop will cause the FOUP handler to drop for a short distance. This is fine under normal conditions, but the door can detach from an overweight FOUP in this scenario.

Non-standard wafers can make FOUPs more difficult to load, leading to a loss of efficiency. In the worst-case scenario, carrying non-standard wafers in standard FOUPS can lead to contamination and yield loss.

Meeting the Need for Backend Advanced Packaging Applications

Entegris is introducing new FOUP designs in order to accommodate new wafer offerings. These include:

• Thin-Wafer FOUPs that contain larger supports to minimize sag, plus a larger pitch that increases space between wafers. This makes it easier for automation to load the FOUP, while decreasing the chance that wafers will contact one another.
• Stacked-Wafer FOUPs that also include an increased pitch, with 20 mm between standard supports. This allows them to accept warped wafers using automation.
• Heavy-Duty FOUPs that are designed with an increased carrying capacity, including a reinforced shell that maintains integrity during emergency stop events. This model can carry 25 wafers up to 1.8 mm thick, and an upcoming version will handle up to 13 stacked and bonded wafers.

In addition, we now offer a contactless horizontal wafer shipper designed to transport the most sensitive wafers. As a non-contact shipper, this solution features rings that support wafers in a unique way, allowing it to accept the shocks and bumps of shipment without transmitting these forces directly to the wafers inside. This product can be used with both standard and non-standard wafers.
 

Watch our animation to get a better picture of how new FOUP form-factors from Entegris can solve the challenge of non-standard wafer designs.

Why Choose New FOUP Form-Factors from Entegris?

Right now, non-standard wafers are proliferating to the extent that ad-hoc solutions aren’t good enough to maintain efficiency, quality, and throughput. Manufacturers are in need of reliable solutions backed by supply chains solid enough to meet their volume requirements. 

Entegris combines decades of experience in FOUP design and manufacturing with a globe-spanning supply chain. For years, our FOUPs have been the go-to solution for front-end-of-line wafer transport, and now we’re taking our expertise to the BEOL. By creating new FOUPs for non-standard wafers, we’re applying our known reputation for reliability and cleanliness to an area that has become crucial for every major semiconductor manufacturer.

For more information on how our new FOUP designs can help you improve yield, capacity, and throughput in 3D stacked wafer applications, contact Entegris today.