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Chapter 35: Chapter 33: Jiangcheng Seventh Middle School, Li Dong

「The next afternoon, in Rongcheng.」

Inside an office at the Huaxuan Technology Sichuan branch, papers were being graded.

The grading panel for this semifinal round consisted of three physics professors from 985 universities and four senior engineers from Huaxuan Technology’s R&D department.

To have such a star-studded grading panel for a high school competition, you had to hand it to Huaxuan Technology.

The conference room was quiet, with only the faint sound of yawning breaking the silence.

Zhang Mo, a senior engineer from Huaxuan Technology’s photolithography R&D team, currently sat before a stack of exam papers, his face a mask of utter boredom.

In truth, he hadn’t wanted to come do this tedious job at all.

’The ”Extreme Ultraviolet Light Source Stabilization System” project back at the company is in a critical phase. I’m already working overtime every day and can’t get it all done, and I still have to find time to grade papers for a bunch of high schoolers?’

But the message from the higher-ups was clear: rather than waiting to scout talent later, it was better to discover and start nurturing it early.

’This is a total waste of time.’

Zhang Mo grumbled to himself.

’Talent isn’t something you can just find on command.’

’Besides, the third part of the experimental question is a technical route our R&D team only managed to crack six months ago. And they expect to find talent with this... in high school?’

’Are they kidding me?’

Zhang Mo had been grading for an hour straight.

Eighty percent of the papers left this question completely blank.

The remaining twenty percent were either unrealistic fantasies or complete fabrications that didn’t conform to engineering logic at all.

”Using gamma-ray lithography,” Zhang Mo read, shaking his head in resignation.

Although gamma rays had high resolution, the engineering challenges of the light source, radiation shielding, and compatible photoresists made it fundamentally impossible to implement in the short term.

Occasionally, a few hit on the right idea, but they all had a typical ”lab mentality,” completely ignoring costs and yield rates.

”Immersion lithography... using a pure water medium to increase the numerical aperture...”

Zhang Mo looked at the paper in his hand and curled his lip.

This was the most mature, standard answer for current mass production. Very safe, but also very uninspired.

Although it was still in widespread commercial use, for an engineer pursuing technological breakthroughs, this kind of answer was like plain water—it quenched your thirst but didn’t excite you.

’Kids these days... they’ve read plenty of books, but they’re missing that spark of ingenuity.’

’Then again, it’s understandable. They’ve never set foot on a production line, so they wouldn’t know the first thing about ’cost’...’

Zhang Mo casually gave the paper a perfect score.

Just as he yawned, wondering whether to order mild or medium spicy for his hotpot that evening, an exam paper made him pause.

[Solution Name: Dual-Beam Laser Interference Maskless Lithography]

He rubbed his eyes and checked again. He wasn’t seeing things.

It was, indeed, Dual-Beam Laser Interference Maskless Lithography.

His mind, which had been groggy just a moment ago, was now wide awake.

This line of thinking was the core idea his team had used to solve that low-cost micro/nano-fabrication problem six months ago!

He hurriedly read on.

”Let two coherent light beams with wavelength λ be symmetrically incident on the photoresist surface...”

”Using spatial geometric constraints, the interference fringe period is d = λ/(2sinθ)...”

”Sub-wavelength resolution verification...”

The more Zhang Mo read, the more shocked—and energized—he became.

Although the student’s solution used the simple harmonic wave superposition formula from high school physics, without employing the complex Fourier optical transforms and vector diffraction theories they used in engineering...

But!

Logically, it was flawless.

And the note at the end made his eyes light up.

[Note: This solution eliminates the need for high-precision mask manufacturing and does not require a projection lens group. Although it has higher requirements for light source coherence and phase stability, it offers a huge cost advantage in the small-batch, high-precision manufacturing of periodic micro/nano-structures.]

He sucked in a sharp breath.

Zhang Mo swallowed and couldn’t help but take a sip of the coffee on his desk.

’This kid’s got a spark. They really know their stuff.’

The student had accurately grasped the two key points for reducing cost and increasing efficiency: ”maskless” and ”lensless.”

Zhang Mo quickly made a mental calculation.

If they were to build a pilot production line for a specific process based on this student’s simplified approach...

...it would eliminate the projection lens, which costs tens of millions, and the mask set, which costs millions.

”Although the cost of a highly coherent, frequency-stabilized light source would double, the overall BOM cost... could be reduced by at least 40%!”

Even he was starting to doubt his own quick calculation.

’For real?’

He quickly pulled out a sheet of A4 paper and began to rapidly verify the calculations.

ΔCost ≈ Cost_Laser_Stable - (Cost_Projection_Lens + Cost_Mask_Set)

He sketched a few simple module diagrams on the paper, muttering to himself.

”If we use the ’beam-splitting prism’ he mentioned in the question for coherent beam splitting, combined with plane mirrors for beam path folding, the machine’s footprint could be shrunk even further...”

If they built an experimental setup following this student’s simplified approach, the cost would be at least 10-15% lower than their current equipment.

”No, I have to get the team to run a simulation first! Following this high school physics approach, maybe we can simplify that damn ’Phase Locking module’!”

At this point, Zhang Mo couldn’t care less about grading discipline. He grabbed the exam paper, stood up, and headed for the door.

A professor next to him asked in surprise.

”Zhang Gong, where are you going? The papers aren’t graded yet.”

It was as if Zhang Mo hadn’t heard him. Well, he actually hadn’t. His mind was completely filled with thoughts of cost reduction.

He left the remaining graders staring at each other in confusion.

”What was that all about?”

”No idea...”

After a brief discussion, they went back to grading the papers in their hands. Who hadn’t had a moment of breaking down while grading, after all?

Just then, another professor picked up an exam paper.

”Hey, I’ve got a good one here. It uses phase-shift mask technology. It’s a bit heavy on theory-dumping, but for a high school student, just understanding this stuff is pretty impressive.”

The paper was passed around among the graders.

The engineers took a look and nodded.

”Mm, solid theoretical foundation. Give it a perfect score.”

But that was all.

This kind of answer was merely at the level of an excellent student. It was a far cry from the kind of talent they were looking for—someone who could provide new ideas for practical engineering applications.

...

Outside in the hallway.

The first thing Zhang Mo did was tear open the seal on the side of the exam paper.

[Exam ID: SC-2022-001]

[School: Jiangcheng City Seventh Middle School]

[Name: Li Dong]

”Jiangcheng Seventh Middle School? Li Dong?”

Zhang Mo muttered the name to himself.

He took out his phone, photographed the section with the experimental question, and added the company’s encrypted watermark.

Then, he wrote a comment.

[The ”dual-beam interference maskless solution” proposed by the candidate (Exam ID SC-2022-001) aligns with my team’s current research focus.

He used the high school principle of simple harmonic wave superposition to fully derive the resolution formula for interference lithography, identified the optimization path of large-angle oblique incidence, and clearly noted the solution’s applicable scenarios and engineering limitations.

The simplified optical path idea he proposed is something we had previously overlooked. I have done a preliminary calculation, and by building an experimental setup based on this idea, the overall cost is estimated to decrease by 15%-20%.

I recommend that my team immediately run an optical simulation and verification based on this approach!]

Tap. Send.

Recipient: Lin Wei, Director of the Huaxuan Technology Photolithography Research and Development Center.

「Meanwhile, at Jiangcheng High-speed Rail Station.」

Li Dong and Zheng Hua were dragging their suitcases.

The two of them had a good ’stress relief’ session in Rongcheng yesterday, only taking a leisurely high-speed train back this afternoon.

Just as they left the station, Zheng Hua patted Li Dong on the shoulder.

”Alright, Li Dong, go home and get some rest today. You can come to school tomorrow.”

Zheng Hua had a smile on his face.

”You must be exhausted from the training camp these past few days. No matter the result, I’m proud of you.”

Li Dong felt Zheng Hua’s concern and asked, moved.

”Um... Teacher Zheng.”

”I was wondering, if... and this is just a hypothetical, if I make it to the finals, that 20,000 yuan prize money... about when would it be deposited?”

The air suddenly went quiet for two seconds.

Then, Zheng Hua suddenly broke into a smile.

In his eyes, this was what you called confidence!

If he wasn’t sure of himself, who would ask about the prize money?

”Don’t you worry!”

”As soon as your results are out and it’s confirmed you’ve made the finals, I’ll go see Principal Wang myself!”

”This money won’t go through the usual reimbursement process. That’s too slow.”

”I’ll apply for it through the school’s ’Special Talent Award Fund’.”

Zheng Hua thought for a moment and gave a rough timeline.

”Once the approval process is done, probably... half a month! It’ll definitely be in your account in about half a month!”

”Half a month?”

Li Dong calculated in his head.

’Half a month from now will be the end of the month. I can still make it in time to buy Mom a new phone for her birthday.’

”That’s great! Thank you, Teacher Zheng! Take care, Teacher Zheng! Be safe, Teacher Zheng!”

Li Dong’s attitude was more affectionate than if he were seeing his own father.

After seeing Zheng Hua off, Li Dong called his mom.

”Hey, Mom, I’m back from the competition.”

”Huh? Didn’t you say you’d be gone for two days?”

Li Qin’s voice came from the other end of the line.

”The competition’s over, so I came back. Nothing else to do.”

Li Dong said casually.

”Mom, where are you? I’m a little hungry.”

”Oh, I’m at your uncle’s house.”

”Your uncle’s been busy at his factory these past couple of days and couldn’t figure out some of the accounts, so he asked me to come over and help.”

”Just come straight here. You can have dinner here tonight.”

”Okay, I’ll head right over.”

Li Dong thought to himself.

’It’s probably not good to go to my uncle’s house empty-handed.’

’Luckily, Teacher Zheng reimbursed everything for this trip, so I haven’t touched the money Mom gave me.’

’Maybe I should buy some fruit?’

There was a fruit stand not far away. Li Dong walked over and was about to pick out some apples.

”Boss, these apples...”

Before he could finish his sentence, he noticed a familiar figure sitting in front of the fruit stand.

”Misha?”