tkworld Chapter 166 First Test
Chapter 166 First Test
2020 11 Month 19 Day.
6:47 a.m.
Su Chen's eyes automatically opened 13 seconds before the alarm clock rang.
This is a habit left over from soldiers—their bodies are more accurate than alarm clocks.
He lay motionless on his cot, staring at the ceiling for about five seconds.
Then he sat up.
Today is February 11.
First test day of 250mm DRIE.
He put on a white cleanroom suit and anti-static gloves, then went to the sink and washed his face. The water was cold, instantly refreshing him.
He glanced at his phone—it was still switched off. He hadn't turned it on since the system integration was completed yesterday.
He doesn't need to know what's happening outside.
He only needs to know one thing: today, 12.05 degrees Celsius.
……
7:15 a.m.
The laboratory lights came on.
Shen Zhiming was the first to arrive. He was 45 minutes earlier than the agreed time.
"President Su." He glanced at Su Chen, who was already standing in front of the equipment checking the parameters, and gave him a light greeting.
"Hmm." Su Chen didn't even look up. "Was the vacuum pump pre-pumped last night?"
"A pre-vacuum was performed. I came to check it at 2 AM, and the vacuum level was stable at 3.1 × 10⁻³ Pa."
"good."
At 7:28, Li Ming arrived.
At 7:35, Chen Guodong arrived.
At 7:41, process engineer Zhao Lin arrived.
At 7:50, everyone had arrived.
There were seven people in total.
Su Chen stood in front of the 250mm DRIE equipment and turned to face his team.
This device took him eight months to design, procure parts, assemble, and debug. The core cavity of the device was manufactured by Chen Guodong and his team in six days and six nights. The pre-compensation components installed on the cavity have angular deviations controlled within ±0.01 degrees and positional deviations controlled within ±5 micrometers.
The calibration procedure was written by Li Ming. The cross-validation errors of both sets were within ±0.005 degrees.
等效热弹性近似法的解析预测值——12.05度——是苏辰在今年7月14日，在他的笔记本第5本第116页上写下的。
That number waited quietly on the notebook for four months and five days.
Today, it will be proven true.
"Everyone," Su Chen's voice was calm and clear, "we've already gone through today's procedures three times, so I won't repeat them. I'll just say one thing—"
He looked around, his gaze sweeping across everyone's face.
"Regardless of the outcome, each of you can be proud of yourself today. No team in the world has ever designed, manufactured, assembled, or calibrated a 250mm DRIE cavity before. We are the first."
He paused.
"Alright. Let's begin."
……
It was exactly 8:00 AM.
The first test has officially begun.
Step 1: Final vacuum level confirmation.
Shen Zhiming read the data from the vacuum pump control panel: "Vacuum level 2.8 × 10⁻³ Pa, meets the standard."
Su Chen nodded: "Proceed to the second step."
Step 2: Pre-charge with SF₆/C₄F₈ gas.
Zhao Lin operated the gas pipeline valves to fill the storage tanks with etching gas SF₆ and passivating gas C₄F₈, respectively. The pressure sensor readings fluctuated in real time on the control panel.
"SF₆ inflation complete, storage pressure 1.2 bar. C₄F₈ inflation complete, storage pressure 0.8 bar."
"Proceed to step three."
Step 3: Plasma ignition test.
This is one of the most critical steps in the entire process—the plasma uniformity within the 250mm cavity directly determines the etching quality. If the plasma distribution within the cavity is uneven, the sidewall angles of the etched surface will deviate from the predicted values.
Li Ming started the plasma power supply on the control panel.
"RF power 600W... Plasma ignition successful."
The spectral analysis window on the control panel displays the emission spectrum of the plasma—the characteristic peaks of SF₆ are clearly visible and evenly distributed.
"Plasma homogeneity test..." Li Ming stared at the data on the screen, and after a few seconds reported the result, "Uniformity deviation 1.2%, within the acceptable range."
苏辰的表情没有变化。1.2%的均匀性偏差对于250mm腔体来说已经非常好了——他们在200mm腔体上的均匀性偏差是0.8%，考虑到尺寸增加了25%，1.2%是一个合理的数字。
"Proceeding to the fourth step. Formal etching."
……
The fourth step is the longest part of the entire process—the Bosch process cyclic etching.
SF₆ etching silicon → C₄F₈ passivation of sidewalls → SF₆ re-etching → C₄F₈ re-passivation — this cycle will be repeated hundreds of times, with each cycle taking about 12 seconds, and the total time is expected to be around 3 hours.
For the entire three hours, Su Chen stood in front of the control panel without sitting down, drinking water, or saying a single unnecessary word.
He stared at the three sets of data that were constantly changing on the screen—
Etching depth.
Sidewall angle.
Cavity temperature.
The first two sets of data are progressing steadily and everything is normal.
However, the third set of data—the cavity temperature—began to change as Su Chen had anticipated when the etching process reached the 47th minute.
"The temperature shift has begun." Su Chen's voice was very soft, but everyone in the laboratory heard it.
Shen Zhiming immediately looked at the temperature monitoring panel—the temperature of the inner wall of the cavity began to rise slowly from the initial 23.0℃.
23.2℃……23.5℃……23.8℃……
This is the effect of thermal expansion.
On a 200mm cavity, this effect caused the sidewall angle to deviate from the expected 8.71 degrees—at the time, everyone thought the etching had failed, until Su Chen presented the derivation of the equivalent thermoelastic approximation method, proving that the 8.71-degree deviation was not a failure, but an inevitable result of the thermal expansion effect.
Now, the same effect is happening in a 250mm cavity—only to a greater extent.
"The pre-compensation system is ready," Su Chen said.
"The pre-compensation system is ready," Zhao Lin replied.
"Start when the etching depth reaches 180 micrometers."
"clear."
Time passed by, second by second.
The cavity temperature continued to rise: 24.0℃…24.3℃…24.7℃…
The etching depth is steadily increasing: 50 micrometers... 80 micrometers... 120 micrometers... 150 micrometers...
By 10:17 a.m., the etching depth had reached 180 micrometers.
"Activate the pre-compensation system." Su Chen's voice remained calm.
Zhao Lin pressed the start button for the pre-compensation system.
The pre-compensation component begins operation—by precisely controlling the thermocouples and fine-tuning mechanisms embedded in the cavity wall, it compensates in real time for deformation caused by thermal expansion.
The design principle of this pre-compensation system is based on the equivalent thermoelastic approximation method derived by Su Chen on pages 112-116 of his fifth notebook.
Compensation direction: radial.
Compensation amount: Calculated in real time based on the analytical solution.
Target sidewall angle: 90 degrees (at a size of 250mm, thermal expansion will cause the sidewall angle to deviate by about 12.05 degrees - the goal of the pre-compensation system is to make up for this deviation).
"The pre-compensation system is operating normally," Zhao Lin reported the data. "The deviation between the compensation amount and the analytical prediction value is within ±0.3%."
Su Chen nodded slightly.
But he knew that whether the pre-compensation system would actually work could only be known after the etching was complete.
There's only one thing we can do now—wait.
……
at the same time.
Shenzhen, Nanshan District, Hongyuan Flying Bird Headquarters.
Lin Wei sat in her office, with no web pages open on her computer screen.
She had been staring at her phone for five minutes—Su Chen's WeChat profile picture was gray, displaying "The other party's phone is switched off."
She knew Su Chen was in the first test.
She knew she couldn't help in any way.
She did everything she could during the live stream the day before yesterday. She spent the entire day yesterday following the news about Bosch's 15 billion yuan investment. Today—
We can only wait today.
Her phone had 317 unread messages—from investors, media outlets, industry associations, members of the Flying Bird Alliance, and even several mid-level officials from central government ministries. Everyone was asking the same question:
When will the 250mm verification results be available?
Lin Wei did not reply to any of them.
Because she didn't know the answer.
All she knew was that Su Chen had said, "Go and speak for me, and I'll stay and do things for you."
So she waited.
……
11:00 AM.
laboratory.
The etching process has been underway for three hours.
The cavity temperature stabilized at 26.3℃, and the etching depth reached 92% of the target value.
everything is normal.
But Su Chen's brow furrowed slightly over the past ten minutes—not because there was a problem with the data, but because he noticed a small fluctuation in the compensation amount of the pre-compensation system in the final stage.
Fluctuation range: ±0.08%.
It's within the normal range, but it's larger than the previous ±0.3%.
"Zhao Lin."
"exist."
"Thermocouple 7 reading."
赵琳查看了7号热电偶的数据："26.31℃……26.33℃……26.29℃……读数有轻微波动，但在±0.05℃以内。"
Su Chen remained silent for a few seconds.
"Continue monitoring. Notify me immediately if the temperature fluctuation exceeds ±0.1℃."
"clear."
The fluctuations did not increase.
At 11:37 AM, the last Bosch loop was completed.
"Etching complete." Li Ming's voice came from the control panel, trembling slightly. "Target depth reached. Cooling down."
No one spoke in the lab.
No one cheered.
Because everyone knows that completing the etching process doesn't guarantee success. What truly determines success or failure is the subsequent measurement phase.
……
It took 40 minutes to cool down.
At 12:17 PM, the cavity temperature dropped to room temperature.
Su Chen personally operated the sampling procedure—removing the etched 250mm silicon wafer from the cavity and placing it on the measurement platform.
This silicon wafer is the world's first silicon wafer to be etched using the Bosch process on a 250mm DRIE equipment.
It looks no different from an ordinary silicon wafer—250 millimeters in diameter, about 0.7 millimeters thick, and its surface reflects a faint iridescent sheen under dust-free lighting.
But beneath its surface lie hundreds of microcavities more than 300 micrometers deep—the angle of the sidewall of each cavity will determine whether Su Chen’s deductions over the past four months are right or wrong.
Su Chen fixed the silicon wafer onto the sample stage of the scanning electron microscope.
"Start measurement."
The scanning electron microscope's probe begins its work, scanning each of the microcavities on the silicon wafer surface. Data is generated on the screen in real time—
The measured values of the sidewall angles popped up one by one.
The laboratory was so quiet that the only sounds were the buzzing of the scanning electron microscope and everyone's breathing.
Su Chen stared at the screen.
Shen Zhiming stared at the screen.
Li Ming stared at the screen.
Chen Guodong stared at the screen.
Zhao Lin stared at the screen.
Everyone was staring at the screen.
Three minutes later, the first set of measurement data came out.
Three lines of numbers were displayed on the screen—
Simulation group A predicted value: 11.98 degrees
Simulation group B predicted value: 12.11 degrees
Analytical prediction using the equivalent thermoelastic approximation method: 12.05 degrees Celsius.
Then, the bottom line—
Measured value: 12.03 degrees
No one spoke in the lab.
Su Chen looked at the number—12.03 degrees.
The deviation is 0.02 degrees compared to the analytical prediction of 12.05 degrees using the equivalent thermoelastic approximation method.
Same as the verification experiment with the 200mm cavity—deviation of 0.02 degrees.
This deviation is within the theoretical error range (0.5%) when the aspect ratio is less than 0.3.
0.5% of 12.05 degrees is 0.06 degrees.
The actual deviation was 0.02 degrees, which is much smaller than the theoretical upper limit of error.
Su Chen's fingers paused on the keyboard for two seconds.
Then he said something—
"Try it again."
……
No one objected.
The second set of measurements was completed after fifteen minutes.
Measured value: 12.04 degrees
The deviation is 0.01 degrees.
Su Chen stared at the numbers on the screen and remained silent for about five seconds.
Then he turned around and faced his team.
His expression didn't change much—no elation, no excitement, no tears welling up.
The corners of her mouth just turned up slightly.
"Verification successful."
Two words.
There was a moment of silence in the lab.
Then--
"good!!!"
Shen Zhiming was the first to shout. His voice echoed between the metal walls of the laboratory, carrying a power that had been suppressed for too long and was finally being released.
"It's done! It's done!!" Li Ming's voice followed closely behind.
Chen Guodong didn't shout. He simply leaned against the equipment rack behind him, closed his eyes, took a deep breath—and then exhaled.
Zhao Lin's eyes reddened.
Su Chen stood there, looking at his team—the people who had worked with him day and night for months—and smiled.
It wasn't the kind of hearty, cheerful laughter.
It is a quiet, confident laugh.
Just like the feeling I had three years ago when I first opened that 280-yuan development board in my rented room in an urban village.
Sure.
"Zhiming," Su Chen said.
"Here!" Shen Zhiming's eyes were still shining.
"Notify General Manager Lin."
"Okay!" Shen Zhiming took out his phone and dialed Lin Wei's number.
The phone rang once and was answered.
"Zhiming?" Lin Wei's voice trembled slightly—she had clearly been waiting for this call.
"President Lin—" Shen Zhiming's voice trembled slightly, "12.03 degrees. Deviation 0.02. Second measurement 12.04. Verification passed."
There was a three-second silence on the other end of the phone.
Then Lin Wei said one word:
"good."
Then the call ended.
Shen Zhiming stared blankly at the phone screen where the call had ended—he had thought Lin Wei would at least say a few more words.
But what he didn't know was—
In the office of Hongyuan Feiniao's headquarters in Nanshan District, Shenzhen, Lin Wei hung up the phone and sat alone in a chair, covering her face with her hands.
She didn't cry.
But her shoulders were trembling slightly.
After a long while, she lowered her hand.
Her eyes were red, but the corners of her eyes were dry.
She picked up her phone and sent Su Chen a WeChat message—even though she knew Su Chen's phone was currently switched off:
"12.03. Got it."
After a few seconds, she added:
"It's time to treat the whole company to dinner."
Then she stood up, walked to the window, and took a deep breath.
The sun shines brightly over Shenzhen outside the window.
She picked up the phone and dialed the public relations department's number.
"Xiao Zhou, get ready. An official statement will be released in half an hour."
"What about the content?"
"The first test of the 250mm DRIE has been completed. The measured sidewall angle is 12.03 degrees, which deviates from the analytical prediction of 12.05 degrees using the equivalent thermoelastic approximation method by 0.02 degrees, confirming successful verification. Attached is the confirmation of the third-party testing appointment—the Testing Center of AVIC 611 Institute, which will issue a formal report within three days."
"clear."
"There's one more thing—"
Lin Wei thought for a few seconds.
Add this line: 'Technology is the only language that doesn't need explanation.'"
"……receive."