Techniques To Identify And Correct Asymmetric Wafer Map Defects Caused By Design And Process Errors


Asymmetries in wafer map defects are usually treated as random production hardware defects. For example, asymmetric wafer defects can be caused by particles inadvertently deposited on a wafer during any number of process steps. In this article, I want to share a different mechanism that can cause wafer defects. Namely, that these defects can be structural defects that are caused by a biased dep... » read more

Developing ReRAM As Next Generation On-Chip Memory For Machine Learning, Image Processing And Other Advanced CPU Applications


In modern CPU device operation, 80% to 90% of energy consumption and timing delays are caused by the movement of data between the CPU and off-chip memory. To alleviate this performance concern, designers are adding additional on-chip memory to their CPUs. Traditionally, SRAM has been the most widely used on-chip CPU memory type. Unfortunately, SRAM is currently limited to a size of hundreds of ... » read more

Improving Semiconductor Yield Using Large Area Analysis


Design rule checking (DRC) is a technique used during chip design to ensure that a device can successfully be manufactured at high yield. Design rules are established based on the limits and variability of equipment and process technologies in use. DRC checking ensures that a design meets manufacturing requirements and will not result in a chip failure or DRC “violation.” Common DRC rules i... » read more

The Impact Of Channel Hole Profiles On Advanced 3D NAND Structures


In a two-tier 3D NAND structure, the upper and lower channel hole profile can be different, and this combination of different profiles leads to different top-down visible areas. The visible area is the key metric to determine whether the bottom SONO layer can be punched through and ensure that the bit cells connect to the common source line. Performing channel hole profile splits on a silicon w... » read more

Improving Gate All Around Transistor Performance Using Virtual Process Window Exploration


As transistor sizes shrink, short channel effects make it more difficult for transistor gates to turn a transistor ON and OFF [1]. One method to overcome this problem is to move away from planar transistor architectures toward 3D devices. Gate-all-around (GAA) architectures are an example of this type of 3D device [2]. In a GAA transistor, the gate oxide surrounds the channel in all directions.... » read more

Improving DRAM Device Performance Through Saddle Fin Process Optimization


As DRAM technology nodes have scaled down, access transistor issues have been highlighted due to weak gate controllability. Saddle Fins with Buried Channel Array Transistors (BCAT) have subsequently been introduced to increase channel length, prevent short channel effects, and increase data retention times [1]. However, at technology nodes beyond 20nm, securing sufficient device performance (su... » read more

A Deposition And Etch Technique To Lower Resistance Of Semiconductor Metal Lines


Copper's resistivity depends on its crystal structure, void volume, grain boundaries and material interface mismatch, which becomes more significant at smaller scales. The formation of copper (Cu) wires is traditionally done by etching a trench pattern in low-k silicon dioxide using a trench etch process, and subsequently filling the trench with Cu via a damascene flow. Unfortunately, this meth... » read more

How Does Line Edge Roughness (LER) Affect Semiconductor Performance At Advanced Nodes?


BEOL metal line RC delay has become a dominant factor that limits chip performance at advanced nodes [1]. Smaller metal line pitches require a narrower line CD and line to line spacing, which introduces higher metal line resistance and line to line capacitance. This is demonstrated in figure 1, which displays a simulation of line resistance vs. line CD across different BEOL metals. Even without... » read more

3D NAND Virtual Process Troubleshooting And Investigation


Modern semiconductor processes are extremely complicated and involve thousands of interacting individual process steps. During the development of these process steps, roadblocks and barriers are often encountered in the form of unanticipated negative interactions between upstream and downstream process modules. These barriers can create a long delay in the development cycle and increase costs. ... » read more

Process Model Calibration: The Key To Building Predictive And Accurate 3D Process Models


The semiconductor industry has always faced challenges caused by device scaling, architecture evolution, and process complexity and integration. These challenges are coupled with a need to provide new technology to the market quickly. In the initial stages of semiconductor technology development, innovative process flow schemes must be tested using silicon test wafers. These wafer tests are len... » read more

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