TW202035765A - Metal-organic chemical vapor deposition device - Google Patents

Abstract

A metal-organic chemical vapor deposition device (MOCVD) is used to the deposition of the semiconductor film, and a cooling structure is configured on the ceiling of the reaction chamber to reduce the temperature gradient and to adsorb the stress to lower the probability of deformation or crack. In deposing the semiconductor film, the precursor enters through the gas injection reaction chamber and is deposed on the heated wafer subtract to form the semiconductor film, which is put on the holder of the susceptor in the reaction chamber. The difference of the temperature between the gas injection and wafer substrate generates the stress, which possibly deforms the chamber. The invention is proposed to reduce the temperature gradient and to absorb the stress.

Description

Organometallic chemical vapor deposition equipment

The invention relates to an organometallic chemical vapor deposition equipment, in particular to an organometallic chemical vapor deposition equipment with a cooling structure that can reduce the temperature difference in a reaction chamber and absorb thermal stress.

Metal organic chemical vapor deposition equipment is used to deposit semiconductor thin films on wafer substrates. The method of depositing semiconductor thin films is to flow through the organic metal reaction source (precursor), and then guide the vapor of the saturated organic metal reaction source into the reaction chamber, mix with other gas reaction sources and deposit on the heated wafer substrate to form a semiconductor film.

Organometallic chemical vapor deposition equipment usually includes a reaction chamber, a gas control and mixing system, a reaction source, and an exhaust gas treatment system. The reaction source includes a gas reaction source and an organometallic reaction source. A gas control system is used to pass the gas reaction source through the organometallic reaction source to absorb its saturated vapor, and then the saturated organometallic vapor reaction source enters the reaction through a gas injection port. Cavity.

The reaction chamber is mainly composed of a chamber wall, a susceptor, and a ceiling disposed on the opposite side of the wafer susceptor. A wafer holder is provided on the wafer stage, and the wafer substrate is placed on the wafer holder. It is necessary to maintain a low pressure (10-760 torr) when depositing semiconductors. In order to activate the wafer substrate to absorb the vapor reaction source, it is usually necessary to heat the wafer substrate through the wafer holder of the wafer susceptor. The large temperature difference between the vapor injection port and the wafer tray causes thermal stress on the wafer carrier and the opposite top plate, which may cause the reaction chamber to be deformed or cracked.

The structure of the cooling system of the organometallic chemical vapor deposition equipment proposed in the present invention can absorb thermal stress and reduce the temperature gradient, thereby reducing the temperature difference and temperature of the top plate.

The present invention provides an organometallic chemical vapor deposition equipment, which can reduce the temperature gradient and absorb thermal stress when depositing semiconductor films, and reduce the deformation or cracking of the top plate.

The present invention provides an organometallic chemical vapor deposition equipment, which includes a central shaft with a plurality of vapor reaction source channels inside; a wafer carrier, the center of the wafer carrier is rotatably connected to the central shaft, the wafer carrier The surrounding part has a plurality of wafer trays for supporting a wafer substrate; a top plate, a reaction chamber is formed between the wafer carrier and the wafer carrier, the center of the top plate is provided with a through hole, and the center An upper protruding edge is provided around the through hole; a gas injector, including a plurality of layers, arranged in the reaction chamber, connected with the central axis, between the plurality of layers and the wafer carrier, and the plurality of layers A plurality of injection ports are formed therebetween, and the plurality of injection ports are communicated with the plurality of steam reaction source channels in the central axis for introducing the steam reaction source into the reaction chamber; an injector fixing plate for fixing gas An injector; and an upper cover plate disposed above the top plate and the injector fixing plate for fixing the top plate and the injector fixing plate, the upper cover plate and the top plate have an airflow gap, wherein the injector is fixed The plate has a central disk and a peripheral disk. The central disk is thicker and is in contact with the top layer of the gas injector. The peripheral disk has a horizontal protruding edge. An air flow through hole is provided around the horizontal protruding edge, and the horizontal protrusion The edge is engaged with the upper protruding edge of the top plate, so that the air flow through hole and the air gap between the top plate and the upper cover plate form a cooling air flow channel, which can guide a cooling flow from the center to the surrounding direction in a radiation manner.

Please refer to the embodiment of FIG. 1, which proposes a metal organic chemical vapor deposition (MOCVD) equipment. The metal organic chemical vapor deposition equipment includes a central shaft 100 and a reaction chamber 800. A plurality of steam reaction source channels (not shown in the figure) are provided inside the central shaft 100, and the steam reaction source is guided into the reaction chamber 800 through the gas injector 500. A wafer carrier 200 is provided in the reaction chamber 800, and a top plate 300 is provided relative to the wafer carrier 200. The central shaft 100 is connected to the gas injector 500, communicates with the steam reaction source channel, and can guide the steam reaction source into the reaction chamber. The gas injector 500 is fixed to the injector fixing plate 600. The top plate 300 and the injector fixing plate 600 are fixedly connected to the upper cover plate 400 with a certain gap. The gap forms a passage for cooling gas to flow, and the cooling gas can be radiatively guided to flow from the center to the outside.

The wafer carrier 200 is provided with a wafer tray 210 for placing wafer substrates. The wafer stage 200 is generally disk-shaped, and the wafer trays 210 are distributed on the wafer stage 200 in an astrolabe. In order to activate the surface of the wafer substrate when depositing a semiconductor thin film, it is usually necessary to heat the wafer substrate through the wafer tray 210. The vapor reaction source uses the gas to pass through the metal-organic precursor to become a saturated vapor reaction source (metal-organic precursor) and other gaseous reaction sources (gas precursor), through the gas channel in the central axis, through the gas The injector 500 enters the reaction chamber 800. The temperature of the part of the gas injector 500 close to the central axis 100 is relatively low, while the temperature near the wafer tray 210 is high due to heating, and the temperature of the reaction chamber 800 is uneven.

In addition, there is a gap between the upper cover 400 and the top plate 300 as a channel for the cooling airflow. When the cooling airflow passes through the gap, there is also a temperature difference between the inside and outside of the top plate 300. Therefore, the top plate 300 is affected by the uneven temperature in the reaction chamber 800 and the external cooling air flow, which causes the top plate 300 to be greatly affected by thermal stress, and is easily deformed or may be broken. The present invention provides a solution and in solving this problem, the design of the top plate structure can quickly reduce the temperature difference and absorb the strain, and reduce the probability of deformation and cracking.

First, the gas injector 500 is fixed by the injector fixing plate 600, and the top plate 300 is provided with a central through hole 310 as an installation space for installing the injector fixing plate 600. The injector fixing plate 600 is arranged in the central through hole 310 of the top plate 300 and connected to the central shaft 100. The gas injector 500 is fixed on the injector fixing plate 600, and the injector fixing plate 600 is then fixed on the upper cover plate 400. As shown in the embodiment of FIG. 1, the gas injector 500 is composed of multi-layer plates, and the outlets between the layers corresponding to the internal channels of the central axis 100 form a flow path for guiding the vapor reaction source into the reaction chamber 800. In particular, in order to improve the efficiency of semiconductor thin film deposition, the layer plate of the gas injector 500 and the top plate 300 can be designed to have concave and convex planes, arranged in a radiation manner, and guide the flow of the reactive vapor source.

Please refer to the embodiment shown in FIG. 2. The injector fixing plate 600 is divided into a central disk 630 and a circumferential disk 610. The central disk 630 and the peripheral disk 610 can be formed as one piece or a two-piece structure. The central disk 630 is connected to the gas injector 500, and is usually designed to be thicker than the circumferential disk 610 and has a better heat conduction effect, can absorb greater stress and conduct heat quickly. The injector fixing plate 600 and the top plate 300 are designed separately. The distance between the injector fixing plate 600 and the top plate 300 and the distance between the central disc 630 and the circumferential disc 610 of the injector fixing plate 600 can be used as buffers to absorb stress and reduce the fear of deformation.

The circumferential disk 610 of the injector fixing plate 600 is thinner to form a horizontal flange, and a through hole 620 is provided around the horizontal flange, which can be used as an outlet for cooling air flow. The top plate 300 is inlaid into the horizontal flange of the injector fixing plate 600. A vertical flange 320 is provided on the edge of the central through hole 310 of the top plate 300 to bear against the horizontal flange of the circumferential disk 610 of the top plate to form an occluding structure. To restrict the flow direction of the cooling flow. The upper cover plate 400 is arranged above the injection top plate 300 with a certain gap, and the gap and the through hole 620 on the horizontal flange of the circumferential disk 610 of the injector fixing plate 600 form a channel.

The cooling fluid enters the upper part of the center plate of the injector fixing plate 600 from the rising passage in the central shaft 100, passes above the circumferential disc 610 of the injector fixing plate 600, and passes through the through hole 620 of the horizontal flange of the circumferential disc. The fixed plate 600 and the top plate 300 are restricted by the occluding structure, and continue to flow into the top of the top plate 300 and continue to flow to the periphery, and finally exhaust, forming a radial airflow. When the cooling fluid is discharged, the controller can be connected to adjust to the best flow rate.

The material of the top plate and the fixing plate of the injector are usually made of quartz, graphite, silicon carbide or stainless steel. In particular, the central disk and the circumferential disk of the injector fixing plate are designed to be separated, and the center disk is made of materials with good thermal conductivity and high thermal conductivity, while the circumferential disk has a small thermal conductivity. For example, the center disk is graphite and the peripheral disk is quartz.

The radii of the center disk and the circumferential disk of the injector fixing plate are different with the design of the wafer tray, and are designed according to the radial temperature distribution, so that it has the ability to optimize stress absorption. The shape and number of through holes on the protruding edge of the peripheral disc are not limited, and have a good flow guiding function, which quickly reduces the temperature gradient of the reaction chamber.

It should be emphasized that this article exemplifies the structure of the cooling system of the metal organic chemical vapor deposition equipment. Due to the radial and internal and external temperature gradients of the deposition equipment and the characteristics of the radiation cooling airflow, the structure of the injection fixed plate and the top plate is proposed. There is a separate structure upwards to absorb stress, and different components interlock with each other to guide airflow, quickly reduce the temperature gradient, and then quickly reduce the thermal stress.

The above embodiments are to illustrate the features of the present invention, and include but should not be construed as limitations of the present invention. The patent scope of the present invention should be defined by the scope of the patent application, and the content of the scope of the patent application should be interpreted in the broadest way.

100: central axis

200: Wafer stage

210: Wafer tray

300: top plate

310: Center through hole

320: vertical protrusion

400: Upper cover

500: gas injector

600: Injector fixing plate

610: Circumferential Disk

620: Through hole

630: Center plate

640: Joint

700: cooling air channel

800: reaction chamber

The drawings are for illustrative purposes, and are not used to limit the scope of the present invention. The drawings are not the entirety of the invention, nor do they indicate that a certain element or a step of the drawing is an essential feature of the present invention. Under special circumstances, parts of the invention can be modified according to the spirit of the invention to achieve the functions of the invention, which should also be included in the scope of the invention. More precisely, the scope of the invention should be defined by the claims .

FIG. 1 illustrates the reaction chamber structure of an organometallic chemical vapor deposition apparatus according to an embodiment of the present invention.

Fig. 2 shows the structure of the reaction chamber of the organometallic chemical vapor deposition equipment in the embodiment of Fig. 1 to illustrate the connection between the top plate, the gas injector and the injector fixing plate.

no

100: central axis

200: Wafer stage

210: Wafer tray

300: top plate

310: Center through hole

320: vertical protrusion

400: Upper cover

500: gas injector

600: Injector fixing plate

610: Circumferential Disk

620: Through hole

630: Center plate

640: Joint

700: cooling air channel

800: reaction chamber

Claims (7)

An organometallic chemical vapor deposition equipment, comprising: a central shaft with a plurality of vapor reaction source channels inside; a wafer carrier, the center of the wafer carrier is rotatably connected to the central axis, the wafer carrier The surrounding part has a plurality of wafer trays for supporting a wafer substrate; a top plate, a reaction chamber is formed between the wafer carrier and the wafer carrier, the center of the top plate is provided with a through hole, wherein the center penetrates An upper protruding edge is provided around the hole; a gas injector, including a plurality of layers, arranged in the reaction chamber, connected with the central axis, between the plurality of layers and the wafer carrier, and between the plurality of layers A plurality of injection ports are formed in between, and the plurality of injection ports are connected with the plurality of steam reaction source channels in the central axis for introducing the steam reaction source into the reaction chamber; an injector fixing plate for fixing gas injection And an upper cover plate disposed above the top plate and the injector fixing plate for fixing the top plate and the injector fixing plate, the upper cover plate and the top plate have an airflow gap, wherein the injector fixing plate It has a central disc and a peripheral disc, the central disc is thicker and is in contact with the top layer of the gas injector, the peripheral disc has a horizontal protruding edge, a gas flow through hole is arranged around the horizontal protruding edge, and the horizontal protruding edge It is occluded with the upper protruding edge of the top plate, so that the air flow through hole and the air gap between the top plate and the upper cover plate form a cooling air flow channel, which can guide a cooling flow from the center to the surrounding direction in a radiation manner. According to the first item of the scope of patent application, the metal organic chemical vapor deposition equipment, wherein the material of the center plate of the injector fixing plate is graphite, and the material of the peripheral plate of the injector fixing plate is graphite. The metal-organic chemical vapor deposition equipment described in item 1 of the patent application, wherein the material of the center plate of the injector fixing plate is quartz, and the material of the peripheral plate of the injector fixing plate is quartz. According to the organic metal chemical vapor deposition equipment described in the first item of the patent application, the central disk of the injector fixing plate has a larger thermal conductivity than the circumferential disk of the injector fixing plate. The metal-organic chemical vapor deposition equipment described in item 1 of the scope of patent application, wherein the material of the center plate of the injector fixing plate is graphite, and the material of the peripheral plate of the injector fixing plate is quartz. According to the organic metal chemical vapor deposition equipment described in item 1 of the scope of patent application, the inner surface of the top plate has a concave-convex surface distributed in a radial shape. For the organometallic chemical vapor deposition equipment described in item 6 of the scope of patent application, wherein any one of the plurality of plates of the gas injector has a concave-convex surface, which is distributed radially and corresponds to the inner surface of the top plate, To form a channel for the reaction vapor source.

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