[0034] Example 1
[0035] Please refer to figure 1 , The present invention provides an etching control method before growth of CVD synthetic diamond, which includes the steps:
[0036] S1. Put the diamond seed crystal into the etching chamber and perform the etching operation;
[0037] S2. The spectrum detector obtains the spectrum data of the plasma above the seed crystal by real-time monitoring according to a predetermined detection method;
[0038] S3. The spectrum detector sends the spectrum data to the controller;
[0039] S4. The controller detects whether there is target data, and if so, the etching is completed; if not, step S2 is executed.
[0040] Specifically, the etching chamber may be an etching chamber specially used for etching the surface of the diamond seed crystal, or a synthetic chamber used for synthesizing diamond. When the synthetic chamber is used, after determining the etching end point After the etching is completed, the normal diamond growth step can be started. The etching operation before the growth of diamond can effectively ensure that the surface of the seed crystal is flattened and etched, thereby ensuring that the surface morphology and crystal quality of the diamond growth are greatly improved. During the etching process, a spectrum measuring instrument is used to read the spectrum data according to a predetermined detection method, and after the spectrum data is converted into electronic data, it is sent to the controller for data processing and comparison to determine whether The etching has been completed. If the etching is completed, the specific operation of normal growth is performed. The target data is that the detected target spectral position changes exceeding a predetermined difference; the target spectral position includes: a carbon atom peak at 437 nm or 493 nm and a carbon molecular peak at 558 nm.
[0041] As a preferred solution, in this embodiment, the predetermined detection method includes: single-point detection, multi-point remote detection, and cyclic motion detection.
[0042] Specifically, the single-point detection is to determine a position and perform fixed detection. The single-point detection is suitable for use in the case of a single seed crystal growing diamond, but it does not exclude the application of multiple diamond growth; Point remote detection is to fix the position of the spectrometer and adjust the direction of the probe of the spectrometer to perform spectrum collection; the cyclic motion detection is to move the position of the spectrometer, in each measurement cycle , Collect spectra from multiple different locations. In view of different needs, determining the use of different measurement methods can ensure the objectivity of the measurement.
[0043] As a preferred solution, in this embodiment, the pre-etching operation is:
[0044] S11. Inject hydrogen gas while matching the microwave of the first predetermined power;
[0045] S12. Continue to increase the gas pressure to the first predetermined pressure, and adjust the microwave power to the second predetermined power;
[0046] S13. After the temperature of the etching chamber reaches the target temperature, oxygen gas is introduced to perform etching.
[0047] Specifically, for the etching of the diamond surface, the diamond etching chamber also needs to have certain conditions, such as pressure value, microwave power value, etc.; if the etching is in the growth process, the microwave source in the etching chamber needs to be The frequency of is adjusted to the first predetermined power, then the carbon source is stopped, and then the etching gas is introduced to perform etching.
[0048] Before the growth, the surface of the seed crystal should also be etched accordingly, that is, hydrogen gas is first introduced, and the preferred flow rate of the hydrogen gas is 100-1000 sccm, and the microwave power is adjusted to the first predetermined power. The first predetermined power is preferably 600-1500W, and then the pressure and microwave power of the etching chamber are continuously increased. When the microwaves of the first predetermined pressure and the second predetermined power are reached, and the etching chamber is After the temperature reaches the target temperature, a certain proportion of oxygen is introduced for etching. The second predetermined power is preferably 2000-4000W; the first predetermined pressure is preferably 15-20 kpa., and the target temperature is preferably 850-1200°C. The etching gas specifically includes oxygen and hydrogen, and the amount of oxygen introduced is 2%-16% of the amount of hydrogen introduced.
[0049] As a preferred solution, in this embodiment, the normal diamond growth operation is:
[0050] S41. Vacuum processing the etching chamber, and pass a microwave source of a third predetermined power into the etching chamber; the preferred value of the third predetermined power is 2000-6000W;
[0051] S42. Adjusting the pressure and temperature in the etching chamber, and introducing a carbon source to perform diamond growth. Specifically, the pressure and temperature mentioned here are subject to the pressure and temperature of normal diamond growth, and there is no specific limitation.
[0052] The carbon source includes methane.
[0053] In the step S4, while performing the normal diamond growth operation, a log is generated and an alarm message is sent to the outside.
[0054] Specifically, the normal diamond growth operation is an ordinary MPCVD synthetic diamond operation method, the adjustment of the pressure and temperature in the etching chamber is performed in accordance with the response standard, the carbon source is methane gas, and the flow rate is The standard implementation of the MPCVD method.
[0055] After the etching is completed, the operator needs to be reminded of the next operation arrangement, that is, an alarm message is issued to the outside, because it is uncertain how many devices are performing simultaneous co-production work, and the alarm information needs to include the equipment number of the production equipment. Then it will execute the operation of growing diamond, send out information to the outside, and make a record in the system.
[0056] As a preferred solution, in this embodiment, the target data is that the detected target spectral intensity change exceeds a predetermined value.
[0057] As a preferred solution, in this embodiment, the target spectral position includes a carbon atom peak at 437 nm or 493 nm and a carbon molecular peak at 558 nm.
[0058] As a preferred solution, in this embodiment, the predetermined value is 15%. Specifically, through research, it is found that during the etching process, the spectrum detector will continuously detect the peaks of carbon atoms and carbon molecules, and the peak intensity will be maintained under the condition that the etching power, pressure and other environmental factors do not change. At a certain relatively stable level. The preferred value range of the predetermined value is 15-30%. When the etching end point is reached, the peak intensity will change significantly. Generally, the peak intensity will change by more than 15%. Therefore, the predetermined value is preferably 15%. However, if the degree of etching needs to be increased, the preferred predetermined value is 30%.
