323: Chapter 323 Holy crap, boss, you can do this too?

"What are the errors for mechanical alignment and optical alignment, respectively?"

"The mechanical alignment error is around 1.2 nanometers, while the optical alignment error fluctuates quite a bit, sometimes reaching over 3.0."

"What about environmental vibration and temperature control?"

"The factory's anti-vibration foundation and the cleanroom's temperature control are all built to the highest standards. The measured data are all within the normal range. The problem isn't the environment; it's the equipment itself."

Zhao Yang didn't speak immediately after hearing this. He leaned back in his seat and thought for a while. The issue with overlay accuracy was most likely not a matter of a single parameter, but rather a lack of proper matching between several subsystems: the positioning accuracy of the wafer stage, the compensation algorithm of the optical alignment system, and the coating uniformity of the photoresist. When these things were layered together, adjusting any single one wouldn't work.

The issue of light source uniformity was actually easier to solve; it was likely that the parameter settings in the exposure dose calibration file were incorrect, or the thermal effect compensation for the lens group hadn't been done properly.

Beside him, Liang Mengsong looked curiously at his young boss. He had seen a lot of news about Zhao Yang, and he had never questioned Zhao Yang's cross-disciplinary abilities.

But he had never heard of Zhao Yang ever researching Lithography machines!

However, judging by the questions his boss had just asked, he was truly an expert!

This wasn't something that could be faked!

The car arrived at the factory entrance, and Liang Mengsong led Zhao Yang directly into the cleanroom. After putting on dust-free suits, masks, and gloves, they passed through the air shower. Inside the yellow light area, rows of equipment had their status lights on.

Several engineers were gathered in front of the Lithography machine. Some were lying on the ground looking at the guide rails of the wafer stage, while others sat before the main control screen repeatedly adjusting parameters. Seeing Liang Mengsong bring Zhao Yang in, they all stopped what they were doing.

Zhao Yang didn't exchange pleasantries with them. He walked to the main control screen of the Lithography machine, pulled up all the parameter records from recent tests, and scrolled through them line by line. After a while, he looked up and asked the young engineer who was adjusting parameters nearby, "When you calibrate, are the optical alignment and mechanical alignment done separately or are they linked?"

"Separately. We do mechanical alignment first, then optical alignment."

The young engineer replied.

"That's likely where the problem lies."

Zhao Yang pointed to two curves on the screen that almost overlapped but had a slight phase difference.

"Mechanical and optical alignment must be calibrated in tandem. If you do mechanical then optical, the optical alignment will amplify the residual error of the mechanical alignment. This is because the optical system resamples during scanning, and at that point, the tiny deviation left by the mechanical alignment will be treated as a normal signal."

The engineers looked at each other. Liang Mengsong stood by without speaking, but his brow was slightly furrowed.

"How do we do tandem calibration? We've tried a few rounds, but the data jitters violently when both systems run simultaneously."

A slightly older engineer asked hesitantly.

Zhao Yang began to explain section by section. He went from the kinematic model of the wafer stage to the sampling frequency of optical alignment, and from the time delay of the compensation algorithm to the processing method of the sensor signals.

He didn't speak in generalities but broke down every step specifically according to the experience in his mind regarding Lithography machine system architecture. Later, he pulled over a whiteboard and used a marker to draw a flowchart, marking the values that several key parameters should be adjusted to.

"The issue with light source uniformity doesn't require adjusting the equipment."

Zhao Yang put down the marker. "It should be an issue with the parameter settings in the exposure dose compensation file. Check the lens thermal effect compensation coefficient; it's highly likely the default value wasn't changed. The low edge dose is because the lens group undergoes slight thermal expansion under long periods of continuous exposure. If the compensation coefficient is wrong, it leads to an edge focus shift."

The older engineer stared at the parameter values on the whiteboard for a while, then turned to look at Liang Mengsong. Liang Mengsong nodded to him, and the group immediately dispersed to rerun the parameters.

Over the next three days, Zhao Yang spent almost all his time in the factory. After the Lithography machine issues were resolved, he successively helped the production line adjust parameter fluctuations in etching uniformity, endpoint detection deviations in CMP, and angle errors in ion implantation.

For every problem, he looked at the data on-site and gave a solution on the spot; not once did he sit down to ponder slowly before coming back to make changes. Initially, the engineers thought this academic star might just provide some suggestions at a macro level, but after a few tuning sessions, everyone realized he wasn't suggesting—he was directly telling them where the problem was, how to fix it, and what the result would be.

"Why is this ion implantation angle set to seven degrees? Try changing it to three degrees."

Zhao Yang stood in front of the ion implanter for two minutes, looked over the process parameter table, and then turned to speak to the process engineer beside him.

"Three degrees? Isn't the conventional setting for that implantation angle usually required to be above seven degrees to avoid the channeling effect?" The process engineer was somewhat hesitant.

"Your crystal orientation here is deflected. A seven-degree margin is too large and will instead cause non-uniform sidewall doping. Try three degrees; it should be fine."

The process engineer tried it, and the resulting test data matched what Zhao Yang had said. He held the printed test data before his eyes and looked at it twice, then turned from the equipment to look at Zhao Yang, wanting to say something but not knowing what.

Liang Mengsong followed Zhao Yang the whole time, his face showing no particular expression.

But the shock in his heart was beyond words, and the look in his eyes as he watched Zhao Yang became increasingly strange.

"Was this truly the ability of the world's top genius?"

Also, had Zhao Yang really never encountered a Lithography machine before? Or had he simply interned at ASML?

But he was so young, and his resume was so clear; it shouldn't be possible at all!

Liang Mengsong was completely baffled, but in the end, he didn't dwell on it further; thinking too much about such things only added to one's troubles.

On the night he finished resolving the last process parameter, Zhao Yang didn't return to the Changcheng city area but slept on a sofa in the factory's lounge for a few hours.

Early the next morning, Liang Mengsong found him with the newly printed test report for the first batch of finished products. The yield data was written on the top line of the report, followed by a comparison table of test parameters.

"Thirty-two nanometers, ninety-two percent yield."

Liang Mengsong placed the report on the table in front of Zhao Yang, looking at him with a complex expression.

"The electrical tests for the first batch of trial production wafers all passed. From the equipment debugging issues until now, it's been less than ten days. We spent less than ten days taking the yield from zero to mass production levels."

After saying this, Liang Mengsong couldn't help but ask one more thing.

"Boss, did you used to work at ASML?"

"Of course not."

Zhao Yang replied to Liang Mengsong while casually picking up the report to look through it.