Qualcomm & Samsung DTCO - Paper 27.4
At IEDM, Qualcomm and Samsung also talked about the DTCO used with the Snapdragon 888 on Samsung's 5LPE node. Qualcomm states that the smallest fin pitch (FP), CGP, metal pitches, and SRAM bitcells were used to achieve a 25% shrink over 7LPP. These changes can be seen in the Ultra High-Density library of 5LPE. However, these shrinks also came with increased risks to the process.
From the start to initial production, Samsung reduced defects by 60% and further reduced this to 2% of the baseline by high-volume manufacturing. 5LPE also experienced excellent yield improvement, faster than 10LPE and 7LPP. Part of this is also due to 5LPE being an incremental improvement over 7LPP.
Qualcomm and Samsung also worked together with DTCO to improve yield greatly, achieving 2.5x lower yield loss for operations at low voltages, which is the primary use case of mobile SoCs. They also reduced the number of defective devices by 9x, which is very significant.
Through continued DTCO, Qualcomm and Samsung also reduced the CPU power draw by 7% and total power by 3%. As process node scaling slows, DTCO will become more and more important to achieving desirable characteristics for chips.
Samsung also compared their 1st generation node, 5LPE, to their 2nd generation node, 5LPP. They showed it achieved a 5% higher performance at the same power. 5LPP is also used in the Snapdragon 8 Gen 1, although marketed under the name of 4LPX.