I Have a Research Support System

When everyone returned to the control room, Luo Yang sat in front of one of the computers and said:

"To measure thin film samples like yours, X-rays should hit the edge of the silicon wafer at a nearly horizontal angle.

It is necessary to ensure that during each test, exactly half of the X-rays are blocked by the silicon wafer, and the other half of the X-rays irradiate the surface of the sample, interact with the sample, and generate diffraction signals, which are finally collected by the signal collector.

In order to prevent the X-rays of the signal collector from being directly irradiated, a lead coin should be placed in front of it to absorb most of the X-rays.

Now let's debug. "

While using programming language to control the instruments in the test cabin, Luo Yang introduced:

"The debugging process is just to tell you, if you don't understand, it won't affect your test.

In the first step, we first move the sample stage in the vertical direction, that is, in the z direction, close to the ground, so that the sample does not block the X-rays at all.

At this time, the signal strength on the detector is almost constant, which is also its maximum value, and this extreme value needs to be recorded.

In the second step, the sample stage is slowly raised until the signal intensity on the detector begins to decrease, which indicates that the sample begins to block the X-rays.

In the third step, let the z coordinate of the sample stage change linearly within a small range, and scan the signal intensity during this period to obtain a curve of the signal intensity changing with the z coordinate.

Find the z-coordinate where the signal intensity is about half of its maximum intensity, and move the sample stage to this z-coordinate.

At this time, it corresponds to the state where half of the X-rays are blocked by the sample.

In the fourth step, we need to calibrate the rotation angle of the sample stage, because we do not know whether the incident X-ray is completely parallel to the sample surface.

Let the rotation angle θ of the sample stage change within a small angle range, scan the signal intensity during this period, and obtain the curve of the signal intensity changing with θ.

Find the θ coordinate corresponding to the maximum signal intensity, and rotate the sample stage to this angle. At this time, the X-ray is parallel to the side of the sample.

The rotation angle at this time is manually set to 0 degrees.

Because we rotated the sample stage, the incident X-ray is no longer half blocked by the sample.

Therefore, the third and fourth steps need to be repeated.

Until the highest value of the sample signal in the fourth step, the corresponding rotation angle is 0 degrees.

As it stands now, we are done debugging. "

"After the debugging is completed, you can test after setting the incident angle. How much is your incident angle?" Luo Yang asked Chen Wanqing.

"Let's say 0.12 degrees." Chen Wanqing said.

Luo Yang typed a piece of code into the computer:

umv-thita 0.12;

Press Enter, and then say:

"After setting up, every time you change the sample, you have to check whether the signal intensity on the detector is close to half of the maximum value.

If the deviation is too large, you need to re-cut the light, that is, repeat the third and fourth steps.

After cutting the light, change the incident angle to 0.12 degrees. "

"The operation of these steps can be found in this user manual. There is a test registration form in it, remember to fill it out." Luo Yang handed the manual to Chen Wanqing and said:

"I left a phone number for you on it, call me if you have something to do, if you want to leave after the test in advance, just go to the master control to turn off the light, and then send me a text message.

The subsequent test software can be operated, so I don’t need to teach it again. "

"No need to teach, I can use the software." Chen Wanqing said.

...

After Luo Yang left, Chen Wanqing said happily: "This time the debugging is relatively fast, it only took more than an hour."

"Yeah, I think Luo Yang knows a lot about instruments, so he should be the teacher here." Xu Qiu glanced at the time and said, "It's almost eleven o'clock in the evening."

"Then let's divide the work. One person is responsible for changing samples, and the other is responsible for testing." Chen Wanqing said.

"Let me change the samples, leave the physical work to me, and test the No. 1 sample that has been installed first." Xu Qiu said.

Chen Wanqing nodded and began to operate the software, setting the sample name, file storage location, and exposure time.

"When testing a new sample, it is usually necessary to test the data of 10 seconds of exposure first to see if there is any problem with the obtained image.

If the surface of the sample to be measured is uneven, the signal intensity in some areas of the image may be too high, even exceeding the detection limit of the instrument. In this case, it is necessary to re-adjust the position of the sample in the test chamber.

If there are no abnormal points in the image, the exposure time can be adjusted to 100 seconds, 200 seconds, 300 seconds or other times.

As long as the maximum signal strength does not exceed 50,000, the higher the exposure time, the better the image quality. "Chen Wanqing said.

No. 1 sample, after 10 seconds exposure test, no abnormal point appears, the highest signal intensity is about 1000.

Because 1000*(300/10)=30000, which is less than 50,000, Chen Wanqing directly changed to 300 seconds exposure time and tested again.

...

Sample No. 1, the test is completed.

Sample No. 2, the test is completed.

Sample No. 3, the test is completed.

...

On sample No. 10, abnormal points appeared. After Xu Qiu reopened the hatch and adjusted the position of the sample, he re-tested, and the abnormal points disappeared. The test is complete.

...

Sample No. 17 had abnormal points again. After Xu Qiu adjusted the position of the sample 4 times, the abnormal points still did not disappear, so he had to give up testing this sample.

...

For sample No. 33, when Xu Qiu was closing the hatch, he was a little anxious and stepped on the pressure sensor in front of the hatch. The hatch opened slowly, and he had to close the hatch again.

...

Sample No. 43, the test is completed.

It was already three thirty in the morning.

Xu Qiu has repeated the operation of opening and closing the hatch door more than 50 times, and he finally understands why this equipment, which costs more than one billion yuan, does not require professionals to keep an eye on it all the time.

Because they are all fool-like operations, although the operation steps are cumbersome, you will be proficient after repeating dozens of times.

It is very difficult to cause damage to the equipment unless the instrument is deliberately destroyed.

Running around is quite tiring, mainly because I have to bend over twice every time I press search 1, and there are always piercing sirens in my ears.

Fortunately, the exposure time of each test is relatively long, during which you can sit and rest for a while.

At this time, both of them were a little sleepy, they ate a little something, gritted their teeth and continued the test.

"Let me change the sample for you, come and rest for a while." Chen Wanqing said.

"Sister, would you change the samples?" Xu Qiu asked.

"Of course, I did the test alone before, and I did all the sample replacement and testing," Chen Wanqing said.

"It's too hard for one person, won't the others come?" Xu Qiu said.

"They don't have samples, so it's not good to force them to help with testing. The main reason is that the previous two tests were done during the day, so it's actually okay." Chen Wanqing said.

"Okay, senior sister, you can go." Xu Qiu sat in front of the test computer.

"Yeah," Chen Wanqing nodded and said, "Mainly I want to move, otherwise I'd almost fall asleep sitting there."