CN111945130A - A kind of arrangement method of filament of hot filament CVD diamond equipment - Google Patents

Abstract

The invention provides a method for arranging filaments of hot filament CVD diamond equipment, which specifically includes the following steps: preparing a number of N of hot filaments, the hot filaments are arranged on the upper end of the base body, the base body is arranged on the upper end of the bottom plate, and the heating filament spacing Tw is from the middle to the upper end of the base plate. The distance between the hot filaments on both sides is different; acid-base corrosion treatment is performed on the substrate on the bottom plate; the treated substrate is put into chemical vapor deposition equipment for diamond coating deposition; the diamond microscopic morphology at four different positions of the substrate is observed and analyzed. Diamond purity and grain orientation, test the bonding strength of the diamond coating and the matrix, as well as the diamond microscopic morphology and purity of the central matrix. The method for arranging the filaments of the hot filament CVD diamond equipment provided by the present invention makes the temperature distribution in the deposition chamber uniform by improving the arrangement of the filaments. The distribution of internal stress is more uniform.

Description

A kind of arrangement method of filament of hot filament CVD diamond equipment

technical field

The invention belongs to the technical field of filaments, and in particular relates to a method for arranging filaments of hot filament CVD diamond equipment.

Background technique

The hot wire chemical vapor deposition method has simple equipment and low cost for preparing diamond coating, and is very suitable for the industrial production of large-area diamond coating. In addition to ensuring the excellent performance of the diamond coating, ensuring the uniformity of the diamond coating performance is another important factor that limits its industrial production. The uniformity of the temperature field and airflow field will seriously affect the diamond coating on the surface of the substrate deposited in the same batch at different positions and the uniformity of diamond nucleation density and growth rate at different positions on the same substrate, thus affecting the uniformity of diamond coating performance. sex. Therefore, the deposition of high-quality diamond coatings requires good stability and uniformity of the physical field near the substrate and the hot filament by changing the deposition conditions.

Ordinary hot filament CVD equipment, the hot filament array will affect the uniformity of the diamond coating on the surface of the substrate, resulting in "edge effect" and "shadow effect", resulting in uneven temperature field on the surface of the substrate, resulting in the center part and edge part of the diamond film. The content of non-diamond components and the stress of the film are quite different, which also leads to a big difference between the morphology of the diamond film under the filament and the morphology of the diamond film between the filaments.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for arranging filaments of hot filament CVD diamond equipment, which solves the technical problem of uneven temperature distribution in the deposition chamber due to the filament arrangement in traditional equipment, and designs a reasonable filament arrangement structure. During the industrial production, the surface morphology and internal stress distribution of the obtained CVD diamond thin film products are more uniform.

A method for arranging filaments of hot filament CVD diamond equipment, specifically comprising the following steps:

Step S1: prepare a number of N of heating wires, the heating wires are arranged on the upper end of the base body, the base body is arranged at the upper end of the bottom plate, and the heating wire spacing Tw is different from the middle to the two sides of the heating wire. Spacing HY, set four positions on the substrate for diamond coating deposition test;

Step S2: pretreating the substrate on the bottom plate, that is, acid-base corrosion treatment;

Step S3: the pretreated substrate is put into the chemical vapor deposition equipment, placed, and the diamond coating is deposited;

Step S4 : observe the diamond micro-morphology at four different positions of the matrix, analyze the diamond purity and grain orientation, test the bonding strength of the diamond coating and the matrix, and test the diamond micro-morphology and purity at five different positions of the central matrix.

In the step S1, the number of hot wires is N=10, _Tw1 =14mm, _Tw2 =10mm, _Tw3 =10mm, _Tw4 =8mm, _Tw5 =8mm, HY=8mm.

In the step S2, the following steps are specifically included:

Step S201 : first use P1500 sandpaper to polish the substrate for 3 minutes, and then continue to polish the substrate with P2000 sandpaper for 3 minutes to remove surface impurities and leave scratches;

Step S202: put the polished substrate into an acid solution (the formula is V(H2SO4):V(H2O2)=1:10) for 20s to remove the cobalt on the surface of the substrate;

Step S203: Ultrasonic treatment for 30min with alkaline solution (namely Murakami solution, the formula is w(KOH):w(K3[Fe(CN)6]):w(H2O)=1:1:10 (mass ratio), corrosion The WC particles on the surface of the substrate expose the cobalt in the surface layer;

Step S204: Continue to use the acid solution for ultrasonic treatment for 3 minutes to remove the metal Co that promotes the graphitization of diamond at a certain depth on the surface of the substrate.

Step S205: Put the matrix into the mixed diamond micropowder acetone suspension for ultrasonic grinding for 30 minutes to increase the defect density on the surface of the matrix. The particle size of the suspension is M0.5/1, M2.5/5, and M5/10 respectively. The diamond powder is added to an appropriate amount of acetone solution according to the mass ratio of 1:1:1 and mixed evenly.

The groove spacing of the molybdenum plate used in the filament fixing device determines the filament spacing. After the filaments arranged at equal intervals are energized, the temperature distribution on the surface of the substrate on the sample stage is uneven, and the surface of the substrate is often guaranteed by rotating the sample stage. Uniformity of temperature distribution. However, if you want to carry out large-scale industrial production, and there are a large number of substrates on the sample stage at the same time, the uniformity of temperature distribution is required to be higher, because the temperature distribution directly determines the uniformity of diamond deposition. The invention adopts the arrangement of filaments with unequal spacing, which ensures the uniformity of temperature distribution on the surface of the substrate from the first step, and reduces the difficulty of subsequent work.

The basic working principle of the present invention is as follows: since the only energy source of the hot filament CVD diamond equipment is the filament, the temperature at the position closer to the filament is higher, and vice versa. When the filaments are arranged at equal intervals, the temperature directly under the filament is the highest, and the temperature at the edge is lower, and the temperature distribution is seriously uneven. By appropriately expanding the distance between the middle filaments and narrowing the distance between the edge filaments, a more uniform temperature field can be obtained.

Using chemical vapor deposition equipment to deposit diamond layers and obtain diamond thin films can be achieved in the prior art, and will not be described in detail here.

The present invention achieves the following remarkable effects:

(1) During the large-scale industrial production of CVD diamond films, the same batch of diamond coatings deposited at different positions on the surface of the substrate, as well as the uniformity of diamond nucleation density and growth rate at different positions on the same substrate, can be ensured. Uniformity of diamond coating properties;

(2) The surface morphology and stress distribution of the diamond film prepared by the filament arrangement of the present invention are more uniform, and the content of non-diamond components is less.

Description of drawings

FIG. 1 is a schematic structural diagram of the placement position of a substrate in an embodiment of the present invention.

FIG. 2 is a schematic diagram of the temperature field distribution of the substrate and the filament in the embodiment of the present invention.

3 is a schematic diagram of the diffraction peaks of the non-diamond component at position 1 in the embodiment of the present invention.

4 is a schematic diagram of the diffraction peaks of the non-diamond component at position 2 in the embodiment of the present invention.

5 is a schematic diagram of the diffraction peaks of the non-diamond component at position 3 in the embodiment of the present invention.

6 is a schematic diagram of the diffraction peaks of the non-diamond component at position 4 in the embodiment of the present invention.

FIG. 7 is a microscopic topography diagram of diamond at position 1 in an embodiment of the present invention.

FIG. 8 is a microscopic topography diagram of diamond at position 2 in an embodiment of the present invention.

FIG. 9 is a microscopic topography diagram of diamond at position 3 in an embodiment of the present invention.

10 is a microscopic topography diagram of diamond at position 4 in the embodiment of the present invention.

11 is a microscopic topography diagram of diamond at point A at position 2 in the embodiment of the present invention.

12 is a microscopic topography diagram of diamond at point B at position 2 in the embodiment of the present invention.

13 is a microscopic topography diagram of diamond at point C at position 2 in the embodiment of the present invention.

14 is a microscopic topography diagram of diamond at point D at position 2 in the embodiment of the present invention.

15 is a microscopic topography diagram of diamond at point E at position 2 in the embodiment of the present invention.

Detailed ways

In order to more clearly illustrate the technical features of the solution, the solution will be described below through specific implementations.

Referring to Fig. 1 and Fig. 2, a method for arranging the filament of a hot filament CVD diamond equipment, specifically includes the following steps:

Step S1: prepare a number of N of heating wires, the heating wires are arranged on the upper end of the base body, the base body is arranged at the upper end of the bottom plate, and the heating wire spacing Tw is different from the middle to the two sides of the heating wire. Spacing HY, set four positions on the substrate for diamond coating deposition test;

Step S2: pretreating the substrate on the bottom plate, that is, acid-base corrosion treatment;

Step S3: the pretreated substrate is put into the chemical vapor deposition equipment, placed, and the diamond coating is deposited;

Step S4 : observe the diamond micro-morphology at four different positions of the matrix, analyze the diamond purity and grain orientation, test the bonding strength of the diamond coating and the matrix, and test the diamond micro-morphology and purity at five different positions of the central matrix.

In the step S1, the number of hot wires is N=10, _Tw1 =14mm, _Tw2 =10mm, _Tw3 =10mm, _Tw4 =8mm, _Tw5 =8mm, HY=8mm.

In the step S2, the following steps are specifically included:

Step S201 : first use P1500 sandpaper to polish the substrate for 3 minutes, and then continue to polish the substrate with P2000 sandpaper for 3 minutes to remove surface impurities and leave scratches;

Step S202: put the polished substrate into an acid solution (the formula is V(H2SO4):V(H2O2)=1:10) for 20s to remove the cobalt on the surface of the substrate;

Step S203: use alkaline solution (10gKOH+10gK3[Fe(CN)6]+100mlH2O), the formula is w(KOH):w(K3[Fe(CN)6]):w(H2O)=1:1:10 (mass ratio)) ultrasonic treatment for 30min, corrode the WC particles on the surface of the substrate, so that the cobalt in the surface layer is exposed;

Step S204: Continue to use the acid solution for ultrasonic treatment for 3 minutes to remove the metal Co that promotes the graphitization of diamond at a certain depth on the surface of the substrate.

Step S205: Put the matrix into the mixed diamond micropowder acetone suspension for ultrasonic grinding for 30 minutes to increase the defect density on the surface of the matrix. The particle size of the suspension is M0.5/1, M2.5/5, and M5/10 respectively. The diamond powder is added to an appropriate amount of acetone solution according to the mass ratio of 1:1:1 and mixed evenly.

The groove spacing of the molybdenum plate used in the filament fixing device determines the filament spacing. After the filaments arranged at equal intervals are energized, the temperature distribution on the surface of the substrate on the sample stage is uneven, and the surface of the substrate is often guaranteed by rotating the sample stage. Uniformity of temperature distribution. However, if you want to carry out large-scale industrial production, and there are a large number of substrates on the sample stage at the same time, the uniformity of the temperature distribution is higher, because the temperature distribution directly determines the uniformity of diamond deposition. The invention adopts the arrangement of filaments with unequal spacing, which ensures the uniformity of temperature distribution on the surface of the substrate from the first step, and reduces the difficulty of subsequent work.

The basic working principle of the present invention is as follows: since the only energy source of the hot filament CVD diamond equipment is the filament, the temperature at the position closer to the filament is higher, and vice versa. When the filaments are arranged at equal intervals, the temperature directly under the filament is the highest, and the temperature at the edge is lower, and the temperature distribution is seriously uneven. By appropriately expanding the distance between the middle filaments and narrowing the distance between the edge filaments, a more uniform temperature field can be obtained.

Using chemical vapor deposition equipment to deposit diamond layers and obtain diamond thin films can be achieved in the prior art, and will not be described in detail here.

In order to further illustrate the technical effect brought by the arrangement method of the filaments in the patent of the present invention, referring to FIG. 2 , it can be seen that the temperature field distribution of the four positions on the substrate is uniform;

Referring to Figures 3 to 6, there are no graphite peaks in the diamond coating of the matrix at four different positions, the characteristic peaks of diamond are obvious and sharp, the purity of diamond is high, and all have good grain orientation, and the three characteristic peaks of diamond are at the same time. appears, and the diffraction intensity of (111) and (220) crystal planes are high, and the diffraction intensity of (311) crystal plane is low, indicating that the diamond grains mainly present (111) and (220) crystal planes. Among the matrix diamond coatings at the four positions, the diffraction intensity of the (111) and (220) crystal planes is the highest at position 2, followed by position 1 and position 3, and finally at position 4, but the difference is not significant, which is due to position 1 The grains at position 2 are slightly coarser, and the grain orientation is good, but the overall difference is not large. The crystal shapes of the four samples are all good, so the diffraction peaks are relatively strong.

Referring to Figures 7-10, it is the SEM images of the morphology of the diamond coating on the surface of the substrate at 4 different positions. It can be seen that the morphology of the diamonds in the coatings of the substrates at four different positions is basically the same, the diamond grains are clear, the crystal edges are obvious and have obvious orientations, mainly showing (111) and (220) crystal planes, and the crystal grains are agglomerated. And connected to each other to form polycrystalline, the grain size is coarse, the grains are densely packed, there are no holes and isolated grains, the coating quality is good, and the surface roughness is large. On the whole, the size of the diamond grains at positions 1 and 2 on the substrate is slightly larger than the grain size of the diamond coating on the surface of the substrate at positions 3 and 4, and the density of the diamond grains in the samples at positions 1 and 2 is low. In position 3 and position 4, it means that the temperature of the surface of the middle substrate is slightly higher than that of the two sides of the substrate, and the gas flow rate is slightly lower than that of the two sides of the substrate. However, by comparing the diamond morphology on the surface of the matrix parallel to the hot filament direction alone, it is found that the grain morphology is not much different.

Referring to Figures 11-15, for the pictures taken by the scanning electron microscope of these five points, choose to observe the diamond surface morphology at different positions of position 2 on the substrate. Select 5 points on position 2 on the base, which are the positions of the four tool nose positions and the position of the tool center, and name them as five points A, B, C, D, and E in turn.

From the SEM images of the diamond surface morphology at five different observation points, it can be seen that the diamond morphology at the four corner positions A, B, C, and D of the tool is basically the same, and the diamond particles are of the same size. The size of the diamond particles is slightly smaller than that of the other four positions, and the particle packing density is slightly larger than that of the other four positions. Combined with the distribution of the temperature field and airflow field above, it can be seen that under this experimental condition, due to the existence of the "hot filament effect", the four corner positions are below the hot filament, so the temperature at the edge of the intermediate substrate is slightly higher than that in the central area, and the airflow velocity It is also slightly smaller at the center of the substrate surface, while it is higher away from the center. The combined effect of the temperature field and the airflow field makes the diamond nucleation density at the center position high, while the growth rate is relatively low, agglomeration and small grain size. , the grain packing density is larger. In general, diamonds have good uniformity and high density. In practical applications, the cutting edges of diamond-coated tools are located at the four corners of the tool. Therefore, the uniformity of diamond growth at the cutting edge and the bonding strength of the coating and the substrate have a significant impact on the performance and stability of the tool. Therefore, , under the deposition conditions, the performance of the coated tool is better. The diamond growth is relatively uniform as a whole, and the actual deposition experimental results are in good agreement with the simulation results.

The specific working process of the present invention:

The detailed operation process has been described in detail before, and will not be described in detail here.

The undescribed technical features of the present invention can be realized by or using the existing technology, and will not be repeated here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Those skilled in the art Changes, modifications, additions or substitutions made within the essential scope of the present invention shall also belong to the protection scope of the present invention.

Claims (3)

1. an arrangement method of hot filament CVD diamond equipment filament, is characterized in that, specifically comprises the following steps: Step S1: prepare a number of N of heating wires, the heating wires are arranged on the upper end of the base body, the base body is arranged at the upper end of the bottom plate, and the heating wire spacing Tw is different from the middle to the two sides of the heating wire. Spacing HY, set four positions on the substrate for diamond coating deposition test; Step S2: pretreating the substrate on the bottom plate, that is, acid-base corrosion treatment; Step S3: the pretreated substrate is put into the chemical vapor deposition equipment, placed, and the diamond coating is deposited; Step S4 : observe the diamond micro-morphology at four different positions of the matrix, analyze the diamond purity and grain orientation, test the bonding strength of the diamond coating and the matrix, and test the diamond micro-morphology and purity at five different positions of the central matrix. 2. The method for arranging the filaments of the hot wire CVD diamond equipment according to claim 1, wherein in the step S1, the number of hot wires is N=10, _Tw1 =14mm, _Tw2 =10mm, _Tw3 =10mm , _Tw4 = 8mm, _Tw5 = 8mm, HY = 8mm. 3. The method for arranging filaments of hot filament CVD diamond equipment according to claim 2, wherein in the step S2, the method specifically comprises the following steps: Step S201 : first use P1500 sandpaper to polish the substrate for 3 minutes, and then continue to polish the substrate with P2000 sandpaper for 3 minutes to remove surface impurities and leave scratches; Step S202: put the polished substrate into an acid solution (the formula is V(H2SO4):V(H2O2)=1:10) for 20s to remove the cobalt on the surface of the substrate; Step S203: Ultrasonic treatment for 30min with alkaline solution (namely Murakami solution, the formula is w(KOH):w(K3[Fe(CN)6]):w(H2O)=1:1:10 (mass ratio), corrosion The WC particles on the surface of the substrate expose the cobalt in the surface layer; Step S204: Continue to use the acid solution for ultrasonic treatment for 3 minutes to remove the metal Co that promotes the graphitization of diamond at a certain depth on the surface of the substrate. Step S205: Put the matrix into the mixed diamond micropowder acetone suspension for ultrasonic grinding for 30 minutes to increase the defect density on the surface of the matrix. The particle size of the suspension is M0.5/1, M2.5/5, and M5/10 respectively. The diamond powder is added to an appropriate amount of acetone solution according to the mass ratio of 1:1:1 and mixed evenly.

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