TWI641720B - Current limiting ring device with shielding baffle, chemical vapor deposition equipment and adjustment method thereof - Google Patents

Abstract

The invention provides a current-limiting ring device with a shielding baffle, a chemical vapor deposition device and an adjusting method thereof. A shielding baffle made of a heat-resistant material is arranged between the inside of the limiting ring and the outside of the tray in the reaction chamber, The board shields all or part of the inner surface of the restrictor ring to block the heat radiation from the heated tray to the cooled restrictor ring, and the shield plate, the combination of the shield plate and the tray, or the shield plate and the restriction plate The combination of the flow loops constitutes a space through which the process gas required for guiding the chemical vapor deposition process flows in the reaction chamber. The invention blocks the high-temperature heat radiation from the tray by a shielding baffle on the inner side of the current-limiting ring, suppresses the deposition of reaction by-products, reduces power consumption, and realizes the adjustment of the temperature field and the flow field in the reaction chamber, thereby effectively improving the process reaction treatment. effect.

Description

Current limiting ring device with shielding baffle, chemical vapor deposition equipment and adjustment method thereof

The invention relates to a chemical vapor deposition device and a method for adjusting the same, and more particularly, to a flow-limiting ring device with a shielding plate in the field of metal organic chemical vapor deposition equipment, and a method for adjusting the chemical vapor deposition process. .

Chemical vapor deposition (CVD) equipment, especially metal organic chemical vapor deposition (MOCVD) equipment, is used to deposit solid materials on wafers. Such materials generally include compounds of elements from Groups III and V of the Periodic Table (referred to as III-V materials, but also including II-VI materials). Furthermore, materials such as silicon (Si), silicon carbide (SiC), and zinc oxide (ZnO) can be deposited on a wafer or other surface. Commercially, these devices are used to make solid-state (semiconductor) microelectronic devices, optical devices, and optoelectronic (solar) devices, as well as other electronic or optoelectronic materials and devices.

As shown in FIG. 1, in the reaction chamber 10 of the conventional MOCVD apparatus, a tray 40 is placed on a rotating shaft 60, and one or more wafers (not shown) are placed in a recess on the upper surface of the tray 40 by the tray 40. ) For carrying; the tray 40 is heated to a desired temperature (for example, about 1000 ° C.) by a heater 50 below it. The reaction chamber 10 is provided with an upper cover 20; a plurality of process gases required for the MOCVD process enter the reaction chamber 10 through the gas interface of the upper cover 20, and a flow field of the process gas is fixed by a restriction ring 30 surrounding the outer side of the tray 40 Restriction, directing the gas flow of the process gas to the tray 40 and the carrier wafer on the tray 40 for chemical reaction to form a deposited film; then, use a vacuum pump to remove the reacted gas (and reaction byproducts, etc.) from the suction hole at the bottom of the reaction chamber 10 Exhaust the reaction chamber 10.

Only when a proper gas flow field and temperature field are designed in the reaction chamber 10 can the reaction process inside the reaction chamber 10 proceed smoothly. However, the cooling liquid pipe is usually distributed inside the restricting ring 30, and the cooling liquid is introduced into the restricting ring 30 through the corresponding cooling liquid interface of the upper cover 20 to cool the restricting ring 30. The temperature of the restrictor ring 30 after cooling (for example, about 100 ° C. or less) is very different from the temperature of the heated tray 40, so that when the process gas passing above the high-temperature tray 40 reaches the restrictor ring 30 outside the tray 40, It is quickly cooled, condenses to produce solid reaction by-products and deposits on the surface of the restriction ring 30; the deposited reaction by-products are relatively loose, and it is easy to flake and block the exhaust holes, thereby affecting the original flow field in the reaction chamber 10, This affects the normal manufacturing process. In addition, the low-temperature current limiting ring 30 also affects the temperature field, and generates a temperature gradient from the center to the edge of the tray 40, so that the temperature at the edge of the tray 40 is lower than the temperature at the center of the tray 40, resulting in wafers located in different areas of the tray 40. The results were inconsistent. In addition, the restriction ring 30 directly receives heat radiation from the tray 40, and then continues to send cooling liquid to cool down, which will increase the power consumption of the device.

An object of the present invention is to provide a current limiting ring device with a shielding baffle in a chemical vapor deposition device, and a method for adjusting a chemical vapor deposition process by the device. The high-temperature heat radiation of the tray can suppress the deposition of reaction by-products, reduce power consumption, and realize the adjustment of the temperature field and the flow field in the reaction chamber, which effectively improves the reaction processing effect of the process.

In order to achieve the above object, the present invention provides a current limiting ring device with a shielding plate, which includes a limiting ring and a shielding plate. A restrictor ring is arranged around the outside of the tray, and the restrictor ring includes a coolant pipe. The shielding plate made of heat-resistant material is arranged between the inside of the restriction ring and the outside of the tray. The shielding plate is fixedly connected to the restriction ring by a fixing device, and there is a gap between the shielding plate and the shielding restriction ring that it covers. The lower part of the inner surface of the restrictive ring is shielded by a shielding plate to block heat radiation from the tray to the restrictive ring and constitute a space for guiding the flow of process gas.

Preferably, the shielding baffle shields a portion of the restriction ring from a portion corresponding to the horizontal position where the tray is located to a portion extending below the tray.

Preferably, the fixing device between the shielding plate and the restrictive ring is a locking screw; the locking screw penetrates the shielding plate to connect to the restrictive ring or penetrates the restrictive ring to connect to the shielding plate.

Preferably, the fixing device is made of a heat-insulating material, or a combination of a locking screw and a heat-insulating substrate, so that the temperature difference between the shielding plate and the restrictor ring is greater than 100 degrees, and the thermal conductivity of the heat-insulating material is less than 0.5 w / (mk).

Preferably, the heat-resistant material of the shielding plate is quartz, ceramic, graphite, tungsten or molybdenum.

Preferably, the space for guiding the flow of the process gas includes the area surrounded by the inner surface of the extension part of the restrictor ring above the tray, or the area surrounded by the inner surface of the extension part of the tray above the tray. The gas is guided to the surface of the tray; or the gap between the inner surface of the shielding plate corresponding to the horizontal position of the tray and extending to the lower part of the tray and the outer edge of the tray forms a gas circulation path for the reaction gas to leave the surface of the tray.

The present invention further provides a chemical vapor deposition device. The reaction chamber provided by the chemical vapor deposition device includes the above-mentioned flow limiting ring device with a shielding baffle. In the reaction chamber, a tray is placed on a rotating shaft and is rotated during processing. The shaft drives rotation; a recess is provided on the upper surface of the tray for placing at least one wafer; a heater is provided below the tray; a reaction chamber is provided with an upper cover, and the upper cover is provided with a gas interface for the process gas to enter the reaction chamber, and a cooling liquid inflow The coolant interface of the coolant pipe in the restriction ring; the shielding plate made of heat-resistant material is located between the inside of the restriction ring and the outside of the tray. The lower part of the surface is shielded to block the heat radiation from the tray to the restriction ring; the process gas in the reaction chamber passes through the space formed by the combination of the shielding baffle and the tray, and flows down to the suction hole provided at the bottom of the reaction chamber.

The invention further provides a method for adjusting a chemical vapor deposition device. The chemical vapor deposition device includes a reaction chamber. The reaction chamber includes a base at the bottom. The base includes a rotating shaft and a tray supported on the top of the rotating shaft. A plurality of wafers are fixed on the surface. The top of the chemical vapor deposition equipment further includes an air inlet device, so that the process gas flows from the top to the upper surface of the tray. A restriction ring surrounds the reaction space between the air inlet device and the tray. The finished baffle is set between the inside of the restrictor ring and the outside of the tray. The baffle shields the lower part of the inner surface of the restrictor ring. The baffle shields the restrictor ring from the vicinity of the horizontal position of the tray and extends to The part below the tray; the control current limiting ring has a first temperature so that the process gas does not decompose and react in advance while the process gas flows above the wafer surface; the wafer surface has a second temperature, and the process gas reaches the tray and crystal After the surface is rounded, the process gas is brought to the second temperature and the reaction treatment is started; the second temperature is higher than the first temperature; the shutter is controlled The third temperature, so that the reacted gas does not form a large amount of deposits when it leaves the tray and the wafer surface reaches the outer edge of the tray, and flows through the gap between the inner surface of the baffle and the outer edge of the tray until the reaction is pumped out. Cavity; the third temperature is higher than the first temperature and lower than the second temperature.

Preferably, the reaction space between the air inlet device and the tray further includes a gas diffusion space located above and a reaction space located below and close to the upper surface of the tray, and the process gas is gradually diffused and mixed in the gas diffusion space, and the process is reached when the reaction space is reached. The gas reacts to form the required deposition material. The upper end of the shielding baffle is located at the upper end of the reaction space, so that the process gas flowing through the restriction ring will not be decomposed in advance, and the process gas flowing through the shielding baffle will not cause a large amount of pollutant deposition.

Preferably, the upper end of the reaction space is located at 3 to 30 mm above the upper surface of the tray.

Compared with the conventional technology, the present invention increases the deposition temperature of side reactants by adding a shielding baffle (which can completely block or partially block the limiting baffle) inside the current limiting ring, so that the heat radiation directly acts on the shielding baffle, Can effectively inhibit or improve the deposition of side reactants. Due to the function of the baffle, the heat radiation of the restrictor ring will be greatly reduced, which can reduce the flow of the coolant and save the power consumption of the equipment. By changing the thickness of the shielding plate, the inner and outer space, etc., the temperature of the restrictor ring can be controlled to adjust the internal temperature field. In a preferred example, only the lower part of the restriction ring is blocked, and the effect of upper and lower heat can be obtained on the inner surface of the restriction ring. The temperature field of the upper and lower heat can significantly improve the flow field.

10‧‧‧ reaction chamber

20‧‧‧ Upper cover

30‧‧‧ current limiting ring

40‧‧‧tray

50‧‧‧ heater

60‧‧‧rotation axis

70, 71, 72, 73, 74, 75‧‧‧

91‧‧‧ Clearance

92‧‧‧ thickness

93‧‧‧ pitch

FIG. 1 is a schematic structural diagram of a conventional metal organic chemical vapor deposition (MOCVD) device and a middle-limiting ring device thereof.

FIG. 2 is a schematic diagram of the structure of the MOCVD apparatus and the middle current limiting ring device according to the present invention.

3 to 8 are schematic diagrams of the structure of the shielding plate according to different embodiments of the present invention.

Fig. 9 is a schematic diagram of the temperature field in the right half of the reaction chamber when the shielding plate shown in Fig. 4 is provided.

Fig. 10 is a schematic view of the flow field in the right half of the reaction chamber when the shielding plate shown in Fig. 4 is provided.

Figure 11 is a schematic diagram of the temperature field in the right half of the reaction chamber when no shielding plate is provided.

Figure 12 is a schematic diagram of the flow field in the right half of the reaction chamber when no shielding plate is provided.

Figure 13 is a schematic diagram of the film growth rate distribution on the surface of the tray, reflecting the reference airflow conditions in Figures 9 to 12.

The invention provides a current-limiting ring device, which is suitable for various chemical vapor deposition (CVD) equipment, especially metal organic chemical vapor deposition (MOCVD) equipment. As shown in FIG. 2, a MOCVD device is provided with a reaction chamber 10, and the reaction chamber 10 is provided with an upper cover 20, which reacts during the process of processing. The vacuum chamber 10 is kept vacuum-tight. The upper cover 20 is also provided with interfaces for various process gases and interfaces for the cooling liquid. A tray 40 is provided in the reaction chamber 10, and one or more notches are provided on the upper surface thereof; one or more wafers are placed in corresponding notches (not shown in the figure) and carried by the tray 40; the tray 40 is heated by a heater 50 below it to a desired temperature (for example, about 1000 ° C). Several kinds of process gases required for the MOCVD process enter the reaction chamber 10 through the gas interface at the upper cover 20, and are guided to the heated tray 40 and the wafer carried by the tray 40 through the restriction ring 30 and the like, and start under high temperature conditions A chemical reaction is performed to form a deposited film on the wafer. The tray 40 is placed on the rotating shaft 60. During the process reaction, the rotating shaft 60 drives the tray 40 to rotate, so that the process gas is uniformly mixed and distributed on the surface of the tray 40 and the wafer. The reaction gas is discharged out of the reaction chamber 10 through a suction hole at the bottom of the reaction chamber 10 by a vacuum pump.

The flow limiting ring 30 is used to limit the flow field of the process gas, so as to obtain a better process air flow on the tray 40 and the wafer surface. Coolant pipes are distributed inside the restrictor ring 30. The coolant is introduced into the restrictor ring 30 through the corresponding coolant interface of the upper cover 20, and the restrictor ring 30 is cooled (the temperature of the restrictor ring 30 after cooling is about Below 100 ° C). The restrictor ring 30 is usually made of a metal material and has a good thermal conductivity. The restriction ring 30 illustrated in FIG. 2 is located inside the cavity wall of the reaction chamber 10 and outside the tray 40, and extends from a certain distance above the tray 40 to a certain distance below the tray 40, so that the process gas diffuses from below the upper cover 20 to The tray 40 and the wafer surface guide the reacted gas from the surface of the tray 40 until it flows to the bottom of the reaction chamber 10 and is discharged. The specific shape and arrangement position of the restrictor ring 30 can be designed according to the actual application requirements; as an example only, the portion of the restrictor ring 30 shown in FIG. 2 extending above the tray 40 is generally straight and the inner diameter is basically the same ; And the portion extending below the tray 40 is generally a horn type, and the inner diameter is gradually enlarged.

In the present invention, a shielding plate 70 is provided in a CVD device (such as a MOCVD device), which is used to implement adjustment and control of the gas field and / or temperature field in the reaction chamber 10. The shielding plate 70 is located in the restriction ring 30 The inside of the tray 40 and the outside of the tray 40; the shielding plate 70 is made of various high temperature resistant materials, such as, but not limited to, quartz, ceramics, graphite, tungsten, molybdenum, and the like. The shielding plate 70 has a low thermal conductivity, and can effectively block the high temperature radiation of the tray 40 to the restriction ring 30, increase the deposition temperature of the reaction by-products, and suppress or improve the deposition of the reaction by-products; and, can suppress or slow down the restriction ring The temperature rise of 30 reduces the use of coolant in the restrictor ring 30 and reduces the power consumption of the device.

The shielding plate 70 may match the shape inside the restriction ring 30. For example, in the example in FIG. 2, the upper portion of the shielding plate 70 is substantially straight, and the inner diameter is substantially the same; and the lower portion of the shielding plate 70 is generally a horn shape, and the inner diameter is gradually enlarged. The shielding plate may not exactly match the shape of the inside of the restricting ring 30. For example, in other examples, the shielding plate 73 as a whole may be a straight cylinder with the same inner diameter (as shown in FIG. 6), or the inside may be small on the inside and large on the inside (or larger and smaller on the inside, as shown in the inside of the shielding plate 74 in FIG. 7). Area)), and so on.

The outer surface of the shielding plate can abut the inner surface of the restrictor ring 30 (not shown in the figure). Alternatively, the outer surface of the shielding plate and the inner surface of the restricting ring 30 may be spaced apart from each other by a certain distance to avoid direct contact between the shielding plate and the restricting ring 30 for heat transfer. Generally, the width of the gap 91 of the shielding plate or the portion thereof to the restriction ring 30 is increased, so that the effect of blocking high-temperature heat radiation is better, but a part of the process gas may flow between the shielding plate and the restriction ring 30; otherwise, the shielding plate Or if the width of the gap 91 to the restriction ring 30 is reduced, the effect of blocking high-temperature heat radiation is reduced, but the process gas can be reduced or prevented from flowing into the gap 91. Preferably, the gap width between the shielding plate and the restrictor ring 30 can be 1 to 2 mm.

Or, in some different examples, different positions between the outer surface of the shutter plate and the inner surface of the restrictor ring 30 in the axial direction (or circumference) of the corresponding shutter plate may have the same pitch or different Pitch. Taking the axial direction as an example, the distance between the upper part of the shielding plate and the upper part of the restrictive ring 30 may be smaller (or greater than) the distance between the lower part of the shielding plate and the lower part of the restrictive ring 30 (as shown in Figures 6 and 7, but Not limited to this). The upper portion of the shielding plate / restriction ring refers to a portion thereof extending above the tray 40, and the lower portion of the shielding plate / restriction ring refers to a portion thereof each extending below the tray 40.

In some examples such as FIGS. 3 and 6, the thicknesses between the inner surface and the outer surface of the shielding plates 70 and 73 are substantially the same. In other examples, the thickness of the shielding plate 74 may be different from top to bottom (or from the circumference) (see FIG. 7). Generally, if the thickness 92 of the shielding plate or a part thereof is increased, the effect of blocking high-temperature heat radiation is better; on the contrary, when the thickness 92 of the shielding plate or a part thereof is reduced, the effect of blocking high-temperature heat radiation is weaker And Figure 8).

In different examples, the shielding plate can be a complete ring structure itself, or it can be formed by combining various structures such as arc segments (distributed on the circumference) or (axially distributed) endless belts. Ring structure. As another example, the complete or combined shielding baffles 70, 73, and 74 may extend up and down to surround the inside of the restrictive ring 30 and cover the entire surface of the restrictive ring 30 (as shown in Figs. 3, 6, and 7); or, Only part of the surface inside the restrictor ring 30 is covered with the shielding plates 71, 72, 75 (as shown in Figs. 4, 5 and 8).

The shielding plate can be an independent structure, and the shielding plate can be connected to the upper cover 20 or the cavity wall (or bottom) of the reaction chamber 10 by an appropriate connecting member; or the shielding plate can also be connected by an appropriate connecting member. It is fixedly connected to the restrictor ring 30 (preferably, there is still a gap 91 between the shielding plate and the restrictor ring 30 after the connection). For example, a horizontal and / or vertical locking screw 80 is provided (as shown in FIG. 5), and the penetrating shielding plate is connected to the restriction ring 30 (or the penetrating current limiting ring 30 is connected to the shielding plate). For another example, an extension section extending outward can be formed at the bottom of the shielding plate, so that it is located below the bottom of the restrictor ring 30 as a position for connecting the locking screw 80. Similarly, it is also possible to form an extension on the top of the shielding plate similar to the one used for connecting the locking screw. The locking screw 80 is preferably made of a thermal insulation material or a thermal insulation material, such as a ceramic material with a thermal conductivity lower than 0.5w / (m.k), or a metal screw and a low thermal conductivity material. The combination of the substrates can reduce the heat flow between the shielding plate and the current limiting ring, and finally make the shielding plate maintain a relatively high temperature during the deposition process, and the limiting ring maintains a low temperature. The temperature difference between the two can be Keep it above 100 degrees.

By using the above-mentioned various examples independently or in combination, for example, by configuring different structures of shielding plates (or shielding structures with variable structures or assembly auxiliary components to make their structures different, etc.), it can be used in CVD equipment. (Such as MOCVD equipment), especially when other components do not need to be changed, achieve different temperature and gas field adjustment effects to meet various processing requirements. The difference in the structure of the shielding plate can be reflected as one or more of the following factors of the shielding plate or its local position, but is not limited to these factors: shape structure, thickness between the inner and outer surfaces, the distance from the outer surface to the restrictor ring, materials, etc. Wait.

In the present invention, a space capable of guiding the flow of the process gas is formed by the inner side of the shielding plate, including but not limited to: an area surrounded by the inner surface of the upper portion of the shielding plate (as indicated by the flow field above FIG. 10), the process gas is Guided from the upper cover 20 to the tray 40 and the wafer surface; and / or, a gap formed between the inner surface of the lower part of the shielding plate and the outer edge of the tray 40 to form a process gas that leaves the surface of the tray 40 after the reaction is discharged by the bottom vacuum pump The gas circulation path (as shown in the flow field on the right in Figure 10).

The different inner diameters of the shielding plate (or parts of the shielding plate) can adjust the flow path of the process gas to or from the surface of the tray / wafer. Including, but not limited to, for example, by adjusting the inner diameter of the upper part of the shielding plate, the position of the tray 40 to which the process gas is guided and the surface of the wafer is controlled, such as deviating the center of the area surrounded by the inner surface of the upper portion of the shielding plate from the tray. 40 center so that the first position of the process gas is not the center of the corresponding tray 40, and for example, the inner diameter of the upper part of the shielding plate is slightly smaller than the diameter of the tray 40, and the process gas is first gathered in the area corresponding to the center of the tray 40 and then diffused to the edge. Area, and so on. For another example, the size of the distance 93 formed between the inner surface of the lower part of the shielding plate and the outer edge of the tray 40 also plays a corresponding role in adjusting the exhaust rate of the process gas to a certain extent.

In addition to directly replacing the shielding plate with a different inner diameter, it can also be shielded by assembling the thickness difference 92 between the inner and outer surfaces on the restrictor ring 30 (or setting / adjusting the outer surface to the restrictor ring 30 with different gaps 91). Plate to adjust the flow space of the process gas inside the shielding plate. As an example, suppose that the shielding plate with an increased thickness of 92 (while keeping the gap 91 with the restrictor ring 30 unchanged) is equivalent to making the space inside the shielding plate smaller; and it is also assumed that the outer surface and the The increase in the clearance 91 of the restrictor ring 30 (while keeping the thickness 92 constant) is also equivalent to reducing the space inside the shutter to achieve adjustment of the process gas flow range or path. Other conditions such as the reduction of the thickness 92 or the gap 91 of the shielding plate, or when the thickness 92 and the gap 91 are changed, can be derived and tested according to the above, and are not listed one by one.

In the present invention, since a high temperature-resistant and low thermal conductivity shielding baffle is used to shield all or part of the inner surface of the current-limiting ring 30, the high-temperature heat radiation from the heated tray 40 is blocked to make the blocked current-limiting The temperature increase at the ring 30 portion is suppressed or slowed (reducing the use of cooling liquid and reducing power consumption), and achieves the effect of adjusting the temperature field in the reaction chamber 10. Compared with the case where the direct contact with the cooled restrictor ring 30 causes the temperature of the process gas leaving from the vicinity of the high-temperature tray 40 to drop sharply (about 1000 ° C. to about 100 ° C.), reaction byproducts are generated. The temperature of the surface of the plate is higher than that of the restrictor ring 30, so that when the process gas leaving from the tray 40 contacts the shielding plate near the tray 40, the temperature change is relatively small, and thus it is not easy to generate reaction by-products.

According to the above description, in different examples, it is assumed that the shielding plate with an increased thickness 92 (while keeping the gap 91 between the outer surface and the restrictive ring 30 unchanged) or the outer surface and the restrictive ring 30 is replaced. The shielding plate with an increase in the gap 91 (while maintaining the same thickness 92) has a relatively high effect of blocking high-temperature heat radiation. better. In addition, assuming that the thickness 92 and the outer surface gap 91 remain unchanged, and the distance 93 between the inner surface of the shielding plate and the outer edge of the tray 40 increases, the high-temperature heat radiation received is reduced, and the temperature of the shielding plate is increased slowly. In addition, other high-temperature resistant materials with different parameters such as thermal conductivity and heat capacity can be considered to make the shielding plate to adapt to different application situations. Other adjustments such as the thickness of the shielding baffle 92, the inner / outer space 93, or the thickness 92, the inner / outer space 93, and the material can be adjusted and tested according to the above, and are not listed one by one.

Considering that the reacted gas leaving the high-temperature tray 40 will contact the cooling restrictor ring 30, the temperature of the reacted gas during the flow suddenly drops and generates loose by-products, so the shielding plate can be mainly arranged outside the tray 40 The area corresponding to the edge (such as Fig. 4, 5 and 8), or the thickness of the shielding plate corresponding to this area (such as Fig. 8), and the adjustment of the space are adjusted to achieve the effect of adjusting the temperature field in the reaction chamber 10. . The setting of the shielding baffle can make the gas from the reaction area reach the exhaust area surrounded by the outer wall of the base below and the inner wall of the reaction chamber before the reaction area is still at a relatively high temperature, such as 200 degrees or more, so that the reaction process gas A large number of decomposed organic molecules will not re-polymerize due to low temperature. Due to the higher temperature of the shielding plate, even a small amount of deposition will be a dense sediment, which will not easily fall off to form particulate pollutants, which will affect the quality of subsequent processes. . With the air inlet device located on the top of the reaction chamber, the process gas flows from the top to the wafer on the upper surface of the tray. The space surrounded by the restriction ring can be divided into the upper gas diffusion space and the lower reaction space close to the upper surface of the tray. The reaction space between the upper end of the shielding plate and the upper surface of the tray in the present invention. In the gas diffusion space, a large number of process gases undergo mixed diffusion during downward diffusion, but the temperature cannot be too high to prevent the process gas from reacting in advance and is not conducive to the quality of the material formed by the deposition. Therefore, the inner wall of the restriction ring needs to be at a low temperature. Therefore, the upper restriction ring is not covered by the baffle. The reaction space is close to the upper surface of the tray, and has different distributions according to the specific design parameters of the reaction chamber. It is usually within 10mm or 30mm above the surface of the tray. The best is Within 3mm, the process gas is heated to the temperature required for the reaction in the reaction space to form a stable and dense layer of deposited material. The reacted gas is driven by the high-speed rotating tray to flow horizontally to the periphery. Therefore, the shielding baffle corresponds to the distribution of the reaction space, so as to obtain the best treatment effect. The height of the upper end of the shielding baffle can be slightly higher than the upper surface of the tray, but it cannot be too high to reach the gas diffusion space above and the lower end of the shielding It can be extended below the lower surface of the tray, so as not to affect the gas flow rate. In a preferred example shown in FIG. 4, the shielding plate 71 mainly extends from the vicinity of the horizontal position of the tray 40 to a certain distance below the tray 40 (there is no or only a small distance above the tray 40). That is, a space for guiding the process gas from the upper cover 20 to the tray 40 and the surface of the wafer is formed on the inner side of the upper part of the restrictor ring 30 (the flow field is schematically shown in FIG. 10). Here, because the process gas directly contacts the upper part of the cooled restrictor ring 30, the temperature of the process gas will not start a chemical reaction before circulating to the tray 40 (illustrated by the temperature field at the top of Figure 9) until the process gas reaches the tray. Only when the temperature rises near 40 and the surface of the wafer does the reaction begin to form a deposited film required by the process.

In addition, the inner side of the lower part of the shielding plate 71 cooperates with the outer edge of the tray 40 to form a gas flow path that guides the temperature-increased reaction gas away from the tray 40 and is drawn out of the reaction chamber 10 (the flow field on the right in FIG. 10 is schematically illustrated in FIG. 9). The temperature field on the right indicates). In this example, the upper part of the shielding baffle 71 is vacant and the upper part of the restrictive ring 30 is exposed. However, the tray 40 is far away from the upper part of the restrictive ring 30, so the upper part of the restrictive ring 30 receives limited heat radiation, and the heating effect is not obvious. The lower part of the baffle 71 shields the lower part of the restrictive ring 30, effectively blocking the high temperature heat radiation of the lower part of the restrictive ring 30 from the tray 40, and also prevents the heated reaction gas from contacting the lower part of the lower restrictive ring 30, so as to suppress the reaction Product deposition.

Under the same reference airflow conditions (as shown in the example of the film growth rate distribution on the surface of the tray shown in Figure 13), Figures 9 and 10 show the partial shielding plate 71 shown in Figure 4 in the reaction chamber (only shown Schematic diagram of temperature distribution and flow field distribution. Figures 11 and 12 are not set When the baffle 71 is shielded, the temperature distribution diagram and the flow field distribution diagram in the reaction chamber (only the right half is shown). From the comparison of the flow field distribution in Figures 10 and 12, it can be found that the shielding plate provided in the present invention can not only improve the deposition of pollutants in the lower half of the inner wall of the restriction ring, but also significantly improve the Air flow field distribution. In Fig. 10, after the reaction, the restrictive ring of the gas flowing at a high speed to a low temperature is rapidly cooled and refracted downwardly into the exhaust passage between the outer wall of the base and the inner wall of the reaction chamber. The other part of the reaction gas does not turn downwards between the contact with the restrictor ring and still maintains a high temperature. During the downward flow, the two gas streams will interfere with each other and eventually form a vortex as shown in FIG. 12. The formation of the vortex will reduce the exhaust flow rate, and because the vortex has instability and uneven distribution, it will indirectly cause uneven air flow distribution on the upper surface of the tray. At the same time, the vortex will blow up some of the pollutants deposited on the exhaust channel to the top to form pollution, and the flow time of the reaction gas in the exhaust channel will increase, more pollutants will be deposited, and the reaction chamber will be opened. The frequency and cost of cleaning up. It can be seen from FIG. 10 that the vortex in the air flow field disappears after applying the shielding plate of the present invention, and the above-mentioned various problems caused by the vortex are also effectively solved. The use of the shielding plate provided at the lower part of the restriction ring of the structure of the present invention can make the temperature distribution between the edge of the tray and the shielding plate more uniform, and no sudden change in temperature will occur, which will further improve the airflow distribution and avoid the generation of vortices.

The position of the restrictor ring corresponding to the symbol 100 in FIG. 9 is blocked, so that the temperature in the area corresponding to the symbol 100 in the reaction chamber (the area inside the shielding plate 71) is significantly higher than that in the corresponding region in FIG. 11, and the pressure is increased. Adjusted about 2 Torr, which increased the rotation stability and reduced the backflow area before the suction port at the bottom of the reaction chamber shown in the right side of FIG. 9 compared to FIG. 11. Therefore, the present invention has a good adjustment effect on the temperature field and the flow field when the CVD (such as MOCVD) process processing is performed in the reaction chamber.

Although the content of the present invention has been described in detail through the above embodiments, it should be recognized that the above description should not be considered as limiting the present invention. Have general knowledge in the field to which this invention belongs After reading the above contents, various modifications and substitutions of the present invention will be apparent to the reader. Therefore, the protection scope of the present invention should be defined by the scope of the attached patent application.

Claims (9)

A restrictor ring device with a shielding baffle includes a restrictor ring that surrounds the outside of a tray in the reaction chamber and extends from a certain distance above the tray to a certain distance below the tray. The edge is close to the bottom of the reaction chamber, the restriction ring includes a coolant pipe, and a shielding plate made of a heat-resistant material is disposed between the inside of the restriction ring and the outside of the tray, and the shielding plate is fixed by The device is fixedly connected to the restricting ring, and there is a gap between the shielding plate and the restricting ring covered by the shielding plate, and the lower part of the inner surface of the restricting ring is shielded by the shielding plate to block from the tray to the restricting ring. The heat radiation of the flow ring constitutes a space for guiding the flow of process gas; wherein the shielding plate shields the portion of the current limiting ring from a portion near the horizontal position corresponding to the tray to a portion extending below the tray, the shielding plate The lower edge is close to the bottom of the reaction chamber. The restricting ring device with a shielding plate according to item 1 of the scope of patent application, wherein the fixing device between the shielding plate and the limiting ring is a locking screw, and the locking screw penetrates the shielding plate and is connected to The restriction ring or the restriction ring is connected to the shielding plate. The current limiting ring device with a shielding plate according to item 1 of the patent application scope, wherein the fixing device is made of a heat insulating material or a combination of a locking screw and a heat insulating substrate, so that the shielding plate and the limiting plate The temperature difference between the flow rings is greater than 100 degrees, and the thermal conductivity of the thermal insulation material is less than 0.5 w / (mk). The current-limiting ring device with a shielding plate according to item 1 of the patent application scope, wherein the heat-resistant material of the shielding plate is quartz, ceramic, graphite, tungsten, or molybdenum. The baffle-restricted ring device according to item 1 of the scope of the patent application, wherein the space for guiding the flow of the process gas includes an area surrounded by the inner surface of the extended portion of the restrictor ring above the tray, or The area surrounded by the inner surface of the extension plate above the tray guides the process gas to the surface of the tray, or the shield plate corresponds to the inner surface of the tray near the horizontal position of the tray and extends to the area below the tray and the inner surface of the tray. The gap between the outer edges of the tray forms a gas circulation path that allows the reacted gases to leave the surface of the tray. A chemical vapor deposition apparatus, wherein a reaction chamber provided by the chemical vapor deposition apparatus includes a restrictor ring device with a shielding baffle as described in any one of claims 1 to 5 of the patent application scope, and the reaction chamber In the process, the tray is placed on a rotating shaft and rotated by the rotating shaft during processing. The upper surface of the tray is provided with a notch for placing at least one wafer, a heater is located below the tray, and a reaction chamber is provided with an upper cover. The upper cover is provided with a gas interface for the process gas to enter the reaction chamber, and a coolant interface for the coolant to flow into the coolant pipe in the restrictor ring, and the shielding plate made of the heat-resistant material is located in the restrictor ring. Between the inner side and the outer side of the tray, the lower part of the inner surface of the restriction ring is shielded by the shielding plate to block heat radiation from the tray to the restriction ring, and the process gas in the reaction chamber passes through the shield. The space formed by the combination of the plate and the tray flows down to the suction hole provided at the bottom of the reaction chamber. A method for adjusting a chemical vapor deposition apparatus, wherein the chemical vapor deposition apparatus includes a reaction chamber including a base at the bottom, the base including a rotation shaft and a tray supported on the top of the rotation shaft, the A plurality of wafers are fixed on the upper surface of the tray. The top of the chemical vapor deposition device further includes an air inlet device, so that the process gas flows from the top to the upper surface of the tray, and a restriction ring surrounds the air inlet device and the tray. In the reaction space, a shielding plate made of a heat-resistant material is arranged between the inside of the restriction ring and the outside of the tray, and the lower portion of the inside surface of the restriction ring is shielded by the shielding plate, and the restriction is blocked by the shielding plate. The method of adjusting the chemical vapor deposition equipment includes the following steps from a position corresponding to the vicinity of the horizontal position of the tray and extending below the tray in the ring: controlling the current-limiting ring to have a first temperature so that the process gas flows to the wafer During the process above the surface, the process gas does not decompose and react in advance; the surface of the wafer is controlled to have a second temperature, and after the process gas reaches the tray and the wafer surface Bringing the process gas to a second temperature and starting a reaction process, the second temperature being higher than the first temperature; and controlling the shielding plate to have a third temperature so that the reacted gas leaves the tray and the wafer surface reaches the A large amount of deposits will not be formed near the outer edge of the tray, and will flow through the gap between the inner surface of the shielding plate and the outer edge of the tray until it is pumped out of the reaction chamber. The third temperature is higher than the first temperature and low. At the second temperature. The method for adjusting a chemical vapor deposition device according to item 7 of the scope of the patent application, wherein the reaction space between the air inlet device and the tray further includes a gas diffusion space located above and a position close to the upper surface of the tray In the reaction space, the process gas is gradually diffused and mixed in the gas diffusion space. When the reaction space reaches the reaction space, the process gas reacts to form the required deposition material. The upper end of the shielding plate is located at the upper end of the reaction space so as to flow through the limit. The process gas of the flow ring will not be decomposed in advance, and the process gas flowing through the shielding plate will not cause a large amount of pollutant deposition. The adjustment method of the chemical vapor deposition equipment according to item 8 of the scope of the patent application, wherein the upper end of the reaction space is located 3 to 30 mm above the upper surface of the tray.