WO2021128643A1

WO2021128643A1 - Semiconductor silicon material consumable growth furnace and preparation method for silicon material

Info

Publication number: WO2021128643A1
Application number: PCT/CN2020/082875
Authority: WO
Inventors: 李辉; 秦英谡; 穆童; 毛瑞川; 张熠
Original assignee: 南京晶升能源设备有限公司
Priority date: 2019-12-25
Filing date: 2020-04-02
Publication date: 2021-07-01
Also published as: CN110923803A; KR20210134830A; CN110923803B; KR102387823B1

Abstract

Provided are a semiconductor silicon material consumable growth furnace and a preparation method for the silicon material. The growth furnace comprises a furnace body, and a heat shield, a heating device and a crucible which are located in the furnace body. The crucible is supported by a crucible shaft which can be lifted and lowered; by lowering the crucible and the crucible shaft and by means of position cooperation of the crucible shaft and a lower heat shield, the center of the bottom of the crucible is overcooled, avoiding the lifting of the heater or the heat shield, so that a thermal field member above the crucible moves, and the attached deposits are scattered and fall into the crucible, thereby improving the crystal purity. The manner of overcooling the center of the bottom of the crucible in cooperation with a thermal field environment produced by means of multiple segments of heaters can not only maintain the height position of the solid-liquid growth interface relative to the heater unchanged, and ensure the stability of the thermal environment at the growth interface, but also form a growth interface where solid protrudes to liquid, facilitating removal of impurities during crystallization and increasing the crystal purity.

Description

Semiconductor silicon material consumable growth furnace and silicon material preparation method

Technical field

The invention belongs to the technical field of a silicon crystal material growth furnace.

Background technique

Silicon materials have excellent properties such as unidirectional conductivity, heat-sensitive properties, optoelectronic properties, and doping properties, and can be grown into large-scale, high-purity crystals. Therefore, they have become an important integrated circuit basic material widely used in the world.

Semiconductor silicon materials are classified according to application scenarios, and can be divided into monocrystalline silicon materials for chips and silicon materials for etching. Among them, the monocrystalline silicon material for chips is the basic raw material for manufacturing semiconductor devices. The monocrystalline silicon material for chips forms a very small circuit structure through a series of wafer manufacturing processes, and then becomes a chip through cutting, packaging, testing and other links, and is widely used In the downstream market of integrated circuits. The silicon material used for etching is processed into semiconductor-grade silicon parts, which are used to etch silicon electrodes on equipment. As the silicon electrodes are gradually corroded and thinned during processing processes such as etching of silicon oxide films, when the thickness of the silicon electrodes is reduced to After a certain degree, new silicon electrodes need to be replaced, so silicon electrodes are the core consumables required for the etching process of wafer manufacturing. Impurities in silicon consumables will not only reduce the service life of the material, but more seriously will pollute the wafers being processed. Considering the high purity requirements of semiconductor materials, silicon consumables require extremely low metal impurities and carbon and oxygen impurities. Therefore, higher requirements are put forward on the impurity control of the growth furnace for preparing silicon consumables.

In the prior art scheme, generally a heating body and heat shield with uniform heat generation are designed to provide a thermal environment. The upper heat shield enters the air pipe, and inert gas is blown from above the crucible. The heating body and heat shield can be lifted upwards. A temperature measuring hole is opened in a fixed position of the side screen for temperature control and cooling. However, this solution also has several shortcomings, including: 1. Lifting the heater or heat shield will cause movement of the thermal field above the crucible, and the attached deposits will be scattered into the crucible, causing pollution, resulting in high impurity content in the finished product. 2. When the inert gas is blown from the top of the crucible, the volatiles deposited in the gas pipe will fall into the crucible, causing pollution; 3. The growth process cannot be controlled and the impurity content of the product is high.

Therefore, a new technical solution is needed to solve the above-mentioned problems.

Summary of the invention

Objective of the invention: The present invention provides a semiconductor silicon material consumable growth furnace, which solves the problem of impurity contamination during the preparation of the material, improves the purity of the material, and meets the requirements of the semiconductor field for ultra-high purity of the material.

The invention also provides a silicon material preparation method using the semiconductor silicon material consumable growth furnace.

Technical solution: In order to achieve the above-mentioned purpose, the present invention can adopt the following technical solutions:

A semiconductor silicon material consumable growth furnace, comprising a furnace body, a heat shield located in the furnace body, a heating device, and a crucible. The interior of the heat shield is a heat insulation cavity, and the crucible and the heating device surrounding the crucible are all located in the heat insulation. In the cavity, the heating device and the heat shield are fixed to each other, and a crucible shaft is arranged under the crucible, and the crucible shaft extends from the bottom of the crucible and passes through the bottom wall of the heat shield; the bottom wall of the heat shield is provided with a supply The shaft hole through which the crucible shaft passes, the cross section of the shaft hole gradually increases from top to bottom; and the crucible shaft has a shaft plug part that matches the shaft hole, and the cross section of the shaft plug corresponds to the same shaft hole. To gradually increase from top to bottom; when the shaft plug portion rises to the highest position, it cooperates with the shaft hole to form a closed state;

It also includes a gas hood located above the crucible, the gas hood facing the bottom of the crucible is provided with blowing holes; one end of the gas hood is connected to an air inlet pipe, and the other end is connected to an air outlet pipe. The air pipe also extends downward from the air hood; the bottom wall of the heat shield is fixed with two straight pipes penetrating the bottom wall; one of the straight pipes is matched with the lower end of the air inlet pipe, and the lower end of the air inlet pipe is telescopic relative to the straight pipe; A straight pipe is matched with the lower end of the air outlet pipe, and the lower end of the air outlet pipe is also telescopic relative to the straight pipe.

Further, the shaft hole is a conical hole, the shaft plug is a conical shaft plug matched with the conical hole, and the conical shaft plug is arranged around the crucible and coaxial with the crucible shaft.

Further, the heating device includes an upper heater, a middle heater, and a lower heater; the upper heater is located above the crucible, the middle heater and the lower heater surround the crucible facility, and the middle heater is located above the lower heater.

Further, the upper heater is connected to the upper electrode and fixed to the top cover of the heat shield through the upper electrode, the upper electrode passes through the heat shield and the furnace body; the middle heater is connected to the middle electrode and passes through the middle electrode and the heat shield The top cover is fixed, the middle electrode passes through the heat shield and the furnace body; the lower heater is connected with the lower electrode and is fixed to the heat shield top cover through the lower electrode, and the lower electrode passes through the heat shield and the furnace body.

Further, the gas hood is fixed above the crucible.

Further, the crucible includes a circular graphite crucible and a circular quartz crucible located in the graphite crucible, and the graphite crucible is supported by the lower crucible shaft.

The method for preparing silicon material using the semiconductor silicon material consumable growth furnace provided by the present invention adopts the following technical solutions:

When growing silicon material crystals, the crucible moves down with the crucible axis; the gas blown from the gas hood above the crucible is blown onto the melt surface in the crucible.

Beneficial effects: Compared with the prior art, the advantages of the technical solution of the present invention are:

By lowering the crucible and the crucible axis, the position of the crucible axis and the lower heat shield is matched to cause the bottom center of the crucible to be too cold, avoiding the way of raising the heater or the heat shield, causing the thermal field above the crucible to move, causing The attached sediments are scattered into the crucible, which improves the purity of the crystal. The supercooling method of the bottom center of the crucible and the thermal field environment created by the multi-stage heater can not only maintain the height position of the solid-liquid growth interface relative to the heater, and ensure the stability of the thermal environment at the growth interface, but also can form a solid convex to the liquid The growth interface facilitates the removal of impurities during the crystallization process and improves the crystal purity. The upper part of the crucible is blown through the gas hood, and the gas in the inlet pipe is blown into the gas hood from bottom to top, so that the volatile matter remaining in the inlet pipe will not directly fall into the melt.

Description of the drawings

Fig. 1 is a schematic cross-sectional view of a semiconductor silicon material consumable growth furnace in the present invention.

Fig. 2 is a schematic cross-sectional view from another angle of the semiconductor silicon material consumable growth furnace of the present invention.

Detailed ways

1 and FIG. 2, this embodiment discloses a semiconductor silicon material consumable growth furnace, including a furnace body 17, a heat shield located in the furnace body 17, a heating device, a crucible, the inside of the heat shield is In the heat-insulating cavity, the crucible and the heating device surrounding the crucible are all located in the heat-insulating cavity. The crucible includes a circular graphite crucible 8 and a circular quartz crucible 9 located in the graphite crucible 8. The graphite crucible 8 is supported by the crucible shaft 7 below. The heating device and the heat shield are fixed to each other. The furnace body 17 has a furnace body upper wall 18 and a furnace body bottom wall 19 respectively. The furnace body 17, the furnace body upper wall 18, and the furnace body bottom wall 19 are all provided with cooling water tanks. The furnace body 17 has two middle electrode holes. And two lower electrode holes, the upper wall 18 of the furnace body is provided with two upper electrode holes, and the bottom wall 19 of the furnace body is provided with a crucible shaft hole and two air pipe holes. An overflow plate 20 is placed on the bottom wall 19 of the furnace body. The overflow plate 20 is provided with a crucible shaft hole and two air pipe holes. The overflow plate 20 is equipped with two support columns 13 with a diameter of 50-60 mm. A lower heat shield 3 is placed on the support column 13, the thickness of the lower heat shield 3 is 100-200mm, and two tracheal holes are opened. The heat shield includes a side heat shield 1, an upper heat shield 2, and a lower heat shield 3. A side heat shield 1 is placed on the lower heat shield 3, two middle electrode holes and two lower electrode holes are opened on the side heat shield 1, and the thickness of the side heat shield 1 is 100-200mm. An upper heat shield 2 is placed on the above-mentioned side heat shield 1, and two upper electrode holes are opened on the upper heat shield 2, and the thickness of the upper heat shield 2 is 100-200 mm. The lower heat shield 3, the heat shield 1, and the heat shield 2 constitute an integral heat shield system. In the heat shield system, the heating device includes an upper heater 4, a middle heater 5, and a lower heater 6. The upper heater 4 is located above the crucible, the middle heater 5 and the lower heater 6 surround the crucible facility, and the middle heater 5 is located above the lower heater 6. The distance between the upper heater 4 and the upper heat shield 2 is 50-70mm, which is fixed by two upper electrodes 14. The upper electrode 14 passes through the upper heat shield 2, the upper electrode hole of the upper flange 18, and is connected to the power supply outside the furnace. . The distance between the middle heater 5 and the side heat shield 1 is 80-100mm, which is fixed by two middle electrodes 16. The middle heater 5 has two wide grooves to facilitate the movement of the elbow pipe 11 without interference. Passes through the side heat shield 1, the middle electrode hole of the furnace body 17, and is connected to the power source outside the furnace body. The distance between the lower heater 6 and the side heat shield 1 is 80-100 mm and is fixed by two lower electrodes 15. The lower electrode 15 passes through the side heat shield 1 and the lower electrode hole of the furnace body 17, and is connected to the power source outside the furnace body. The distance between the middle heater 5 and the lower heater 6 is 30-50 mm.

A crucible shaft 7 is provided below the crucible, and the crucible shaft 7 extends from below the crucible and passes through the bottom wall of the heat shield, that is, the lower heat shield 3. The bottom wall of the heat shield is provided with a shaft hole for the crucible shaft to pass through, and the cross section of the shaft hole gradually increases from top to bottom; and the crucible shaft 7 has a shaft plug portion 71 that matches the shaft hole. The cross section of the shaft plug portion 71 corresponding to the shaft hole also gradually increases from top to bottom; when the shaft plug portion 71 rises to the highest position, it cooperates with the shaft hole to form a closed state. In this embodiment, the shaft hole is a conical hole with a cone angle of 90-120°. The shaft plug 71 is a conical shaft plug fitted with the conical hole, and the conical shaft plug is arranged around the crucible and coaxial with the crucible axis.

It also includes a gas hood located above the crucible, the gas hood facing the bottom of the crucible is provided with blowing holes; one end of the gas hood is connected to the gas inlet pipe 11, and the other end is connected to the gas outlet pipe 111, which is bent downward from the gas hood Extend, the air outlet pipe also extends downward from the gas hood. The bottom wall of the heat shield is fixed with two straight pipes 12 passing through the bottom wall; one of the straight pipes 12 is matched with the lower end of the air inlet pipe 11, and the lower end of the air inlet pipe 11 is telescopic relative to the straight pipe 12; the other straight pipe 12 Cooperating with the lower end of the air outlet pipe, the lower end of the air outlet pipe 111 is also telescopic relative to the straight pipe 12. In this embodiment, the lower end of the air inlet pipe 11 and the lower end of the air outlet pipe and the upper end of the straight air pipe 12 are snap-connected to be able to slide up and down in the straight air pipe 12. When the crystal is growing, one end of the inlet pipe 11 is introduced with high-purity argon gas, and the outlet pipe is pumped. The gas circulates in the gas hood 10 to sweep the melt surface, take away volatiles and impurities, and improve the purity of the crystal. The gas in the inlet pipe 11 is blown into the gas hood from bottom to top, so that the volatile matter remaining in the inlet pipe will not directly fall into the melt. When the crucible and the crucible shaft 7 move downwards, the air inlet pipe 11 and the air outlet pipe 111 move together with the graphite crucible 8, and the straight air pipe 12 is fixed. The inner diameter of the air inlet pipe 11 and the outlet pipe 111 is 40-60mm, the pipe wall thickness is 5-7mm, the straight air pipe 12 has an inner diameter of 65-75mm, and the pipe wall thickness is 5-7mm.

The center of the lower heat shield 3 is opened to match the conical surface of the crucible shaft 7. When the crucible shaft 7 moves downwards, the two originally attached conical surfaces gradually separate the distance, increasing the relative area and increasing Heat leakage in the center of the bottom of the crucible, gradually increase the degree of subcooling to provide crystallization driving force, avoid raising the heater or heat shield, causing the thermal field above the crucible to move, causing the attached deposits to fall into the crucible. With the decrease of the crucible position, and the thermal field environment created by the above-mentioned multi-stage heater, the height position of the solid-liquid growth interface relative to the heater can be maintained unchanged, ensuring the stability of the thermal environment at the growth interface, and the growth from solid to liquid can be formed. The interface facilitates the removal of impurities during the crystallization process and improves the crystal purity.

The present invention also provides an embodiment of a silicon material preparation method using the above-mentioned semiconductor silicon material consumable growth furnace.

The preparation method includes: when the silicon material crystal is grown, the crucible moves downward with the crucible axis; and the gas blown from the gas hood above the crucible is blown onto the melt surface in the crucible. When the crucible axis 7 moves downwards, the two originally attached conical surfaces gradually separate the distance, increase the relative area, increase the heat leakage at the bottom of the crucible, and gradually increase the degree of subcooling to provide crystallization driving force and avoid lifting The heater or heat shield makes the heat field above the crucible move, causing the attached deposits to fall into the crucible. With the decrease of the crucible position, and the thermal field environment created by the above-mentioned multi-stage heater, the height position of the solid-liquid growth interface relative to the heater can be maintained unchanged, ensuring the stability of the thermal environment at the growth interface, and the growth from solid to liquid can be formed. The interface facilitates the removal of impurities during the crystallization process and improves the crystal purity.

There are many methods and ways to implement the technical solution in the present invention, and the above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention. All the components that are not clear in this embodiment can be implemented using existing technology.

Claims

A semiconductor silicon material consumable growth furnace, comprising a furnace body, a heat shield located in the furnace body, a heating device, and a crucible. The inside of the heat shield is a heat insulation cavity, and the crucible and the heating device surrounding the crucible are all located in the heat insulation. The cavity is characterized in that the heating device and the heat shield are fixed to each other, and a crucible shaft is arranged under the crucible, and the crucible shaft extends from the bottom of the crucible and passes through the bottom wall of the heat shield; the bottom of the heat shield The wall is provided with a shaft hole for the crucible shaft to pass through, and the cross section of the shaft hole gradually increases from top to bottom; and the crucible shaft has a shaft plug part matched with the shaft hole, and the cross section of the shaft plug part is the same as The corresponding shaft hole is also gradually enlarged from top to bottom; when the shaft plug portion rises to the highest position, it cooperates with the shaft hole to form a closed state;

It also includes a gas hood located above the crucible, the gas hood facing the bottom of the crucible is provided with blowing holes; The air pipe also extends downward from the air hood; the bottom wall of the heat shield is fixed with two straight pipes penetrating the bottom wall; one of the straight pipes is matched with the lower end of the air inlet pipe, and the lower end of the air inlet pipe is telescopic relative to the straight pipe; A straight pipe is matched with the lower end of the air outlet pipe, and the lower end of the air outlet pipe is also telescopic relative to the straight pipe.
The semiconductor silicon material consumable growth furnace according to claim 1, wherein the shaft hole is a conical hole, the shaft plug is a conical shaft plug matched with the conical hole, and the conical shaft plug is arranged around the crucible And coaxial with the crucible axis.
The semiconductor silicon material consumable growth furnace according to claim 2, wherein the heating device includes an upper heater, a middle heater, and a lower heater; the upper heater is located above the crucible, and the middle heater and the lower heater The device surrounds the crucible facility and the middle heater is located above the lower heater.
The semiconductor silicon material consumable growth furnace according to claim 3, wherein the upper heater is connected to the upper electrode and fixed to the top cover of the heat shield through the upper electrode, and the upper electrode passes through the heat shield and the furnace body; The middle heater is connected to the middle electrode and fixed to the top cover of the heat shield through the middle electrode, the middle electrode passes through the heat shield and the furnace body; the lower heater is connected to the bottom electrode and is fixed to the top cover of the heat shield through the bottom electrode, The electrodes pass through the heat shield and the furnace body.
The semiconductor silicon material consumable growth furnace according to claim 1, wherein the gas hood is fixed above the crucible.
The semiconductor silicon material consumable growth furnace according to claim 1, wherein the crucible comprises a circular graphite crucible and a circular quartz crucible located in the graphite crucible, and the graphite crucible is supported by the lower crucible shaft.
A method for preparing silicon material using the semiconductor silicon material consumable growth furnace according to any one of claims 1 to 6, characterized in that the crucible moves downwards with the crucible axis when growing silicon material crystals; blowing out from the gas hood above the crucible The gas is blown onto the melt surface in the crucible.