CN103824903B - Substrate processing method for improving emission compensation temperature measurement accuracy or consistency - Google Patents
Substrate processing method for improving emission compensation temperature measurement accuracy or consistency Download PDFInfo
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- CN103824903B CN103824903B CN201210462738.0A CN201210462738A CN103824903B CN 103824903 B CN103824903 B CN 103824903B CN 201210462738 A CN201210462738 A CN 201210462738A CN 103824903 B CN103824903 B CN 103824903B
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- 239000000758 substrate Substances 0.000 title claims abstract description 87
- 238000009529 body temperature measurement Methods 0.000 title claims abstract description 15
- 238000003672 processing method Methods 0.000 title claims abstract description 9
- 238000000034 method Methods 0.000 claims abstract description 21
- 238000005498 polishing Methods 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims abstract description 10
- 238000001514 detection method Methods 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000001312 dry etching Methods 0.000 claims description 7
- 238000009499 grossing Methods 0.000 claims description 6
- 230000000737 periodic effect Effects 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 2
- 239000000523 sample Substances 0.000 abstract description 19
- 238000012545 processing Methods 0.000 abstract description 10
- 238000012360 testing method Methods 0.000 abstract description 2
- 238000002310 reflectometry Methods 0.000 description 11
- 229910052594 sapphire Inorganic materials 0.000 description 11
- 239000010980 sapphire Substances 0.000 description 11
- 150000004767 nitrides Chemical class 0.000 description 8
- 235000012431 wafers Nutrition 0.000 description 7
- 230000005855 radiation Effects 0.000 description 6
- 238000005259 measurement Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- -1 nitride Chemical class 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 230000005457 Black-body radiation Effects 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 210000002858 crystal cell Anatomy 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 238000003909 pattern recognition Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/10—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a light reflecting structure, e.g. semiconductor Bragg reflector
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Led Devices (AREA)
Abstract
The invention discloses a substrate processing method for improving emission compensation temperature measurement accuracy or consistency, and relates to the technical field of LED material engineering. The method comprises the following steps: for a substrate whose probe light wavelength is transparent, performing double-face polishing processing on a flat substrate, performing flattening and smooth processing on the surface of the front pattern of a graphical substrate, maintaining homogeneity of geometrical characteristics of a figure structure, and performing polishing processing again on the back surface of the graphical substrate; and for a substrate whose probe light wavelength is nontransparent, only performing front-surface polishing processing on a flat substrate, performing flattening and smooth processing on the surface of the front pattern of a graphical substrate, and maintaining homogeneity of geometrical characteristics of a figure structure, the flexibility, angularity and aggregate thickness of the processed flat substrates or graphical substrates being smaller than 15 micrometers. According to the invention, through processing the flat substrates or the surfaces of the graphical substrates, the substrate surface uniformity is improved, and the test precision is improved.
Description
Technical Field
The invention relates to the technical field of LED material engineering, in particular to a processing method of a substrate used on LED epitaxial material growth equipment, which can improve the accuracy or consistency of an emission compensation type temperature measurement mode.
Background
Metalorganic chemical vapor deposition (MOCVD) equipment or techniques are currently widely used in the industry for the fabrication of compound semiconductors. It can be used to epitaxially grow monocrystalline crystals of III-V compounds, such as nitride, phosphide and arsenide, and II-VI compounds, such as oxide and sulfide, on a certain substrate material. Most of the materials are wide bandgap semiconductors, and have various applications in the electronic and optoelectronic industries, for example, the materials are used for manufacturing light emitting diodes, laser diodes, photodiodes, solar photovoltaic cells, field effect transistors, high electron mobility transistors and the like.
In the MOCVD equipment, a temperature control system is one of the most important components, and can be roughly divided into two modules: the temperature measuring module and the temperature control module. Because under certain pressure conditions, when various reactants are prepared, the temperature mainly determines the physical and chemical properties of the material, such as phase change, crystallization degree, microstructure and the like. In some applications, the accuracy or consistency of the temperature control system in measuring and controlling the reaction temperature is significant for material quality, parameter yield, and product reproducibility. For example, when a multi-quantum well (MQW) epitaxial structure of a nitride Light Emitting Diode (LED) is grown on MOCVD, the dominant wavelength of the emission spectrum of the final product LED device sensitively changes with the synthesis temperature of MQW. For example, when the synthesis temperature of the MQW changes by 1 ℃, the dominant wavelength of the LED changes by about 2-5 nanometers. The grading specification of the LED product to the dominant wavelength is generally controlled below +/-2.5 nanometers, so that the importance of accurately or reproducibly controlling the MQW synthesis temperature to the yield of the LED dominant wavelength can be seen.
In the prior art, an emission compensation type temperature measurement method is a common temperature measurement method on MOCVD equipment. The entity of this method is called an emission compensated thermometer, which is the measurement module of the temperature control system. Referring to fig. 1, an emission compensation type thermometer is located at a view port position of an upper portion of an MOCVD reaction chamber, and calculates a temperature of a target sample by measuring a thermal radiation intensity and a reflectivity of the target sample. The calculation principle can be deduced through a Planck blackbody radiation formula and a kirchhoff radiation law, and the specific expression is as follows:
wherein,Tit is the temperature of the sample that is,λthe detection wavelength of the thermometer (i.e. the wavelength of the light source at which the reflectance of the sample is measured),α t is the absorption rate of the sample and is,E t is the intensity of the thermal radiation of the sample at the wavelength lambda,c 1 、c 2 is a constant.
In addition, with respect to wavelengthλFor a sample which is not transparent, the absorption rate and the reflection rate can be obtained according to the energy conservation law as follows:
wherein,R t is the reflectivity of the measured sample.
Formula (II)、Intensity of heat radiation of medium sampleE t And reflectivityR t Are all measured by an emission-compensated thermometer and are further measured by a formulaThe temperature of the sample is obtained.
In general, the reflectivity of the sample surface needs to be accurately measured by using a half-space integrating sphere, but the design of observing the reflectivity of the epitaxial wafer on the MOCVD system is difficult to realize. A simple approximation is to reserve an observation port above the reaction chamber, collect and observe the reflectance over a fixed spatial solid angle, while also measuring the thermal radiation intensity. However, this method has a limitation that if the surface of the epitaxial wafer or the substrate sample is rough or is prone to diffuse reflection, the measurement signal of the reflectivity will be weak or have a large error. This can lead to "pattern recognition" errors in the test software or inaccurate, inconsistent and reproducible temperature calculations. The reflectivity detection achieves maximum signal-to-noise ratio and maintains high accuracy or consistency only when the sample surface is in an ideal mirror plane.
Disclosure of Invention
In view of the foregoing limitations of the prior art on the applicability of the emission compensated thermometer, it is an object of the present invention to provide a method for processing a substrate that improves the accuracy or consistency of emission compensated temperature measurements. The uniformity of the surface of the substrate is improved by processing the surface of the flat substrate or the patterned substrate, so that the testing precision is improved.
In order to achieve the above object, the technical solution of the present invention is implemented as follows:
a substrate processing method for improving accuracy or consistency of emission compensation temperature measurement is provided, wherein the substrate is a bearing substrate for material growth in preparation of a light emitting diode product. The method comprises the following steps: for the substrate with transparent detection light wavelength, the flat substrate adopts double-sided polishing treatment; and then carrying out a dry etching process on the front surface of the flat substrate to manufacture a pyramid-shaped pattern to form a patterned substrate, carrying out flattening and smoothing treatment on the surface of the pattern on the front surface of the patterned substrate, keeping the uniformity of the geometric characteristics of the pattern structure, and carrying out re-polishing treatment on the back surface of the patterned substrate. For a substrate which is not transparent to the detection light wavelength, the flat substrate is subjected to only the front-side polishing treatment. And then carrying out a dry etching process on the front surface of the flat substrate to manufacture a pyramid-shaped pattern, forming a patterned substrate, carrying out flattening and smoothing treatment on the surface of the pattern on the front surface of the patterned substrate, and keeping the uniformity of the geometric characteristics of the pattern structure. The processed flat substrate or patterned substrate has bow, warp and total thickness variation of less than 15 μm.
In the above substrate processing method, the pattern structure includes a shape and a geometric size of the periodic unit.
By adopting the method, the processed substrate can easily form mirror reflection, and the reflection signal can be enhanced when the emission compensation type thermometer is used, so that the accuracy and consistency of temperature measurement are improved.
The invention is further described with reference to the following figures and detailed description.
Drawings
FIG. 1 is a schematic view of a measurement of an emission compensated thermometer on a MOCVD system;
FIG. 2 is a schematic view of the processing of a flat substrate transparent to the probe wavelength in the present invention;
FIG. 3 is a schematic illustration of the processing of a patterned substrate transparent to the probe wavelength in accordance with the present invention;
FIG. 4 is a reflected light path of probe light exiting an emission-compensated thermometer through a roughened backside substrate;
FIG. 5 is a view showing a reflection path of a substrate after the probe light emitted from the emission compensation type thermometer has been processed by the present invention.
Detailed Description
Referring to fig. 2 and 3, the processing method of the invention comprises the following steps: for the substrate with transparent detection light wavelength, the flat substrate adopts double-sided polishing treatment; and then carrying out a dry etching process on the front surface of the flat substrate to manufacture a pyramid-shaped pattern to form a patterned substrate, carrying out flattening and smoothing treatment on the surface of the pattern on the front surface of the patterned substrate, keeping the uniformity of the geometric characteristics of the pattern structure, and carrying out polishing treatment on the back surface of the patterned substrate. For the substrate with non-transparent detection light wavelength, the flat substrate is only subjected to front polishing treatment; and then carrying out a dry etching process on the front surface of the flat substrate to manufacture a pyramid-shaped pattern, forming a patterned substrate, carrying out flattening and smoothing treatment on the surface of the pattern on the front surface of the patterned substrate, and keeping the uniformity of the geometric characteristics of the pattern structure. The smaller the roughness of the substrate surface after the polishing treatment, the better, so that specular emission is easily formed. The pattern structure includes the shape and geometry of the periodic cells.
A 2-inch patterned sapphire substrate is used as an example to illustrate one embodiment of the present invention.
Firstly, cutting the sapphire single crystal into wafers with the size of 2 inches along the direction of a 0.2-degree deflection angle (deflection m-plane) of a c-plane, wherein the plane corresponding to a flat edge is the a-plane of the sapphire crystal cell, and the opening angle of the flat edge to a c-axis is 30 degrees. In addition, the thickness of the Wafer is in the range of 420-440 micrometers; bow, warp and total thickness variation should be less than 15 microns;
and secondly, carrying out double-sided polishing treatment on the sapphire Wafer, wherein the higher the polishing fineness is, the better the polishing fineness is, namely, the smaller the surface roughness is, the better the polishing fineness is. Preferably, the surface roughness after polishing should be kept at least below 0.5 microns;
and thirdly, selecting the front surface of the sapphire to carry out a dry etching process, and manufacturing a Pyramid (Pyramid) pattern with the diameter of 2.6 microns, the height of 1.65 microns and the period size of 3 microns. In the process, the process parameters should be optimized to ensure the geometric uniformity of the pattern size and the smoothness and flatness of the pattern surface. Or adding an auxiliary process, and reducing the roughness of the surface of the graph as much as possible by adopting a physical or chemical method.
When the patterned sapphire substrate manufactured through the three steps is used for growing the nitride LED epitaxial structure on the MOCVD system adopting the emission compensation type thermometer, the uniformity and the consistency of parameters such as the dominant wavelength of the LED epitaxial wafer can be improved.
Taking the example of epitaxial growth of a nitride LED structure on MOCVD by using a sapphire substrate, when an LED epitaxial wafer grows to an MQW layer, the nitride, the sapphire substrate and a graphite carrying disc plated with SiC are jointly combined to be a temperature measurement target of the emission compensation type thermometer. If the light source wavelength used in the thermometer for measuring the reflectance is 930 nm, the wavelength is transparent to the nitride, the sapphire substrate, and the SiC on the surface layer of the graphite plate, and this time is approximately specularThe GaN surface of (a) also provides advantages for the measurement of reflectivity and thermal radiation intensity. Given that the surface condition of the graphite disk and the SiC coating is uniform and invariant, the substrate surface condition will primarily affect the reflectance measurement accuracy or uniformity. Taking a flat substrate as an example, 930 nm light will be reflected and refracted at three interfaces between air and nitride, nitride and sapphire substrate, and sapphire substrate and air. Referring to FIG. 4, the light path of the reflected light reaching the back surface of the substrate is shown, and if the back surface of the substrate is rough and the light is diffusely reflected, the reflectivity of the temperature measurement object will be reduced, according to the formula、The calculated temperature will be lower than the actual value, thereby causing temperature measurement errors. On the contrary, if the back surface of the substrate is polished, the uniformity of the reflection condition of the back surface of the substrate is improved. As shown in fig. 5, it is easier to form mirror reflection, so that the reflection signal can be enhanced and the temperature measurement accuracy or consistency can be improved. Similarly, it has been demonstrated that for a substrate that is not transparent at the detection wavelength, polishing the front side of a flat substrate or substantially improving the geometric uniformity of the patterned substrate surface pattern and the smoothness and flatness of the surface can also increase the reflectivity signal strength while improving the accuracy or uniformity of reflectivity and temperature measurements.
The foregoing discloses only exemplary embodiments of the invention. For those skilled in the art, the technical idea of the embodiment of the present invention should be changed in the specific embodiments and the application scope, which belong to the protection scope of the present invention.
Claims (2)
1. A substrate processing method for improving accuracy or consistency of emission compensation temperature measurement is provided, wherein the substrate is a bearing substrate for material growth in preparation of a light-emitting diode product, and the method comprises the following steps: for the substrate with transparent detection light wavelength, the flat substrate adopts double-sided polishing treatment; then, carrying out dry etching process on the front side of the flat substrate to manufacture a pyramid-shaped pattern to form a patterned substrate, carrying out flattening and smoothing treatment on the surface of the pattern on the front side of the patterned substrate, keeping the uniformity of the geometric characteristics of the pattern structure, and carrying out re-polishing treatment on the back side of the patterned substrate; for the substrate with non-transparent detection light wavelength, the flat substrate is only subjected to front polishing treatment; and then carrying out a dry etching process on the front surface of the flat substrate to manufacture a pyramid-shaped pattern, forming a patterned substrate, carrying out flattening and smoothing treatment on the surface of the pattern on the front surface of the patterned substrate, and keeping the uniformity of the geometric characteristics of the pattern structure.
2. The substrate processing method of claim 1, wherein the geometric features of the pattern structure comprise shapes and geometric dimensions of periodic cells.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210462738.0A CN103824903B (en) | 2012-11-16 | 2012-11-16 | Substrate processing method for improving emission compensation temperature measurement accuracy or consistency |
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| CN201210462738.0A CN103824903B (en) | 2012-11-16 | 2012-11-16 | Substrate processing method for improving emission compensation temperature measurement accuracy or consistency |
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| CN103824903B true CN103824903B (en) | 2017-04-12 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1717976A1 (en) * | 1988-10-25 | 1992-03-07 | Восточно-Сибирский технологический институт | Temperature control method |
| US5388909A (en) * | 1993-09-16 | 1995-02-14 | Johnson; Shane R. | Optical apparatus and method for measuring temperature of a substrate material with a temperature dependent band gap |
| RU2148802C1 (en) * | 1999-01-27 | 2000-05-10 | Институт физики полупроводников СО РАН | Device for detection of heat radiation |
| CN1545140A (en) * | 2001-03-28 | 2004-11-10 | 株式会社东芝 | Substrate temperature measuring method |
| CN1608199A (en) * | 2001-12-26 | 2005-04-20 | 沃泰克工业有限公司 | Temperature measurement and heat-treating methods and system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002214414A (en) * | 2001-01-22 | 2002-07-31 | Omron Corp | Optical element with thin resin film having micro-rugged pattern, method for producing the same and apparatus therefor |
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- 2012-11-16 CN CN201210462738.0A patent/CN103824903B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1717976A1 (en) * | 1988-10-25 | 1992-03-07 | Восточно-Сибирский технологический институт | Temperature control method |
| US5388909A (en) * | 1993-09-16 | 1995-02-14 | Johnson; Shane R. | Optical apparatus and method for measuring temperature of a substrate material with a temperature dependent band gap |
| RU2148802C1 (en) * | 1999-01-27 | 2000-05-10 | Институт физики полупроводников СО РАН | Device for detection of heat radiation |
| CN1545140A (en) * | 2001-03-28 | 2004-11-10 | 株式会社东芝 | Substrate temperature measuring method |
| CN1608199A (en) * | 2001-12-26 | 2005-04-20 | 沃泰克工业有限公司 | Temperature measurement and heat-treating methods and system |
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