TW202221832A - Vertical furnace and vertical boat used therefor - Google Patents

Abstract

The present invention provides a new type of boat used in a vertical furnace. The slots in such boat have improved surface roughness and tilt angle. With the new boat herein, the contact area with wafers can be reduced, and thus the defects of the wafer edge and the overall uniformity of the film during the process are improved.

Description

High-yield wafer boat for vertical furnace tubes

The present invention relates to a vertical wafer boat for carrying wafers in a vertical furnace tube, specifically, a vertical wafer boat for heat treatment, oxidation, diffusion, CVD (chemical vapor deposition) and other processes.

Furnace tube equipment is widely used in semiconductor manufacturing for many processes such as diffusion deposition, oxidation, annealing, etc. Among them, the diffusion deposition process is mainly used to produce thin films on substrates (eg, semiconductor wafers). When processing through a vertical furnace tube, it is generally desirable to have better uniformity and fewer surface defects in the thin film on the substrate.

During wafer processing, it is usually necessary to introduce reactive gases into a furnace tube and diffuse the reactive gases in the furnace tube onto the surface of the substrate to produce the desired thin film. Therefore, it is very important that the reaction gas in the furnace tube is evenly distributed on the substrate. Generally speaking, furnace tube equipment can be divided into horizontal furnace tube and vertical furnace tube. Among them, the reactor of the vertical furnace tube is arranged in an upright manner, and is widely used because of its small overall footprint. In the conventional vertical furnace tube, the wafer carrier is supported by the wafer surface on the horizontal groove of the wafer boat, and the reaction gas is introduced into the furnace tube cavity through a gas injector, and diffuses to the carrier. Wafers on a wafer boat to achieve the purpose of thin film formation. However, when the wafer is carried in the wafer boat of the conventional design, the contact area between the wafer and the wafer boat's carrying surface (eg, the slot surface) is large and completely covered, so the reaction gas cannot be released. The reaction occurs uniformly on the wafer surface, and defects are prone to occur where the wafer contacts the carrier surface, so that the obtained wafer surface and film on the surface may be non-ideal.

It is against this background that the present invention arises.

In view of this, according to an embodiment of the present invention, a novel wafer boat for vertical furnace tubes is provided, which includes: an upper plate body, a lower plate body, a bearing rod body, and a supporting rod body. The upper plate body is the fixed plate at the top of the vertical crystal boat; the lower plate body is the positioning plate at the bottom of the vertical crystal boat; the support rod is the support column for strengthening the structure of the crystal boat; The carrier surface between the slots (also called "groove teeth", "groove surface", or "slot surface") is the main structure of the carrier wafer. The supporting rod body and the three bearing rod system of the wafer boat are connected between the upper plate body part and the lower plate body part. The crystal boat is integrally arranged in the inner tube of the vertical furnace tube and extends along the extending direction of the vertical furnace tube. In addition, when the wafer is placed in the wafer boat, the wafer is horizontally supported on each bearing surface of the wafer boat.

In one embodiment, each part of the wafer boat is made of quartz. In one embodiment, the length directions of the support rod body and the bearing rod body are parallel to each other, and two ends of each rod body are respectively connected with the planes of the upper plate body and the lower plate body. In one embodiment, the groove surface on the carrier rod body of the wafer boat is an inclined surface, and the angle between the groove surface and the horizontal surface is between 8° and 10°.

According to an embodiment of the present invention, a vertical furnace tube is provided, which includes an outer tube, an inner tube, a wafer boat, and a plurality of gas injectors. The inner tube is arranged inside the outer tube. The wafer boat is arranged inside the inner tube and used for carrying wafers. In one embodiment, the wafer boat has three carrying rods and one supporting rod, wherein the first carrying rod, the second carrying rod, the third carrying rod, and the supporting rod are separated from each other by a predetermined distance. arranged by distance. In one embodiment, the groove surfaces of the above-mentioned three bearing rods are roughened by the special technology of the present invention (for example, it may include steps such as groove forming, roughening, etching, cleaning, etc.), and the roughening degree reaches Ra>10um surface roughness.

Other aspects of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings.

The objects, advantages and features of the present invention will become more apparent from the following detailed description of several embodiments and the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a clearer understanding of the embodiments of the present invention. However, the disclosed embodiments may be practiced even in the absence of some or all of these details. In some instances, well-known structures and operations have not been described in detail to avoid unnecessarily obscuring the disclosed embodiments. Although numerous specific details are set forth for the purpose of explanation, it should be understood that they are not intended to limit the disclosed embodiments. When specific embodiments are described in relative terms (eg, "upper" and "lower," "top" and "bottom," "inner" and "outer," etc., these terms are Not intended as a limitation. Furthermore, it is to be understood that the various embodiments shown in the figures are schematic and not necessarily drawn to scale.

FIG. 1 is a schematic cross-sectional view of a vertical furnace tube 100 according to an embodiment of the present invention. As shown in FIG. 1 , the vertical furnace tube 100 includes an outer tube 102 , an inner tube 104 , a vertical wafer boat 106 , a gas injector 108 , a gas supply part 110 , and a base 120 . Wherein, the inner tube 104 is arranged in the outer tube 102, and the outer tube 102 and the inner tube 104 are arranged in the form of concentric circles, and the outer tube 102 and the inner tube 104 are separated by a predetermined distance. In some embodiments, the outer tube 102 and the inner tube 104 are made of quartz. In addition, the vertical wafer boat 106 is disposed in the inner tube 104 and on the base 120, and is used for horizontally carrying the wafer W to be processed thereon. In some embodiments, the vertical boat 106 is made of quartz. The gas injector 108 is used to deliver one or more reaction gases from the gas supply part 110 to the interior of the vertical furnace tube 100 . Various embodiments of the high-yield vertical wafer boat 106 of the present invention will be described below with reference to FIG. 2 and FIG. 3 .

According to an embodiment of the present invention, FIG. 2 and FIG. 3 respectively show a side view and a perspective view of the vertical wafer boat 106 . The vertical wafer boat 106 includes a rod body part and a plate body part, wherein the rod body part includes a first carrying rod body 112 , a second carrying rod body 114 , a third carrying rod body 116 , and a supporting rod body 118 , and the plate body The part includes the first plate body 122 and the second plate body 132 . In one embodiment, each of the first carrier rod 112 , the second carrier rod 114 , and the third carrier rod 116 has the same number of grooves arranged at equal intervals. In addition, each of these grooves has a carrier surface (ie, the surface that contacts the wafer, and may also be referred to as a "groove", "groove surface", or "slot surface" to support the wafer )"). In one embodiment, the bearing surface of each groove is inclined. For example, the angle θ between the bearing surface 140 of each groove and the horizontal surface 142 is between about 8° and 10°. In addition, the bearing surface of each groove can be roughened to make the surface roughness (Ra) >10 μm, as shown in the schematic diagram of FIG. 4 . In one embodiment, the support rod 118 is a solid quartz cylinder, which is used to provide support for the wafer boat body, so as to strengthen the overall structural strength of the wafer boat. It should be noted that although not all grooves on the carrier rods are shown in FIG. 2 for brevity, it should be understood that the grooves on the carrier rods may be distributed throughout their entire length, or part of the entire length.

As mentioned above, the vertical wafer boat 106 also includes the first plate body 122 and the second plate body 132. FIG. 5 shows a bottom view of the vertical wafer boat 106 (ie, a view of the bottom surface of the first plate body 122). The first plate body 122 is located at the bottom of the vertical wafer boat 106 and is the base of the vertical wafer boat 106 . The first plate body 122 enables the vertical wafer boat 106 as a whole to be stably set upright on the base (eg, the base 120 ) of the furnace tube (eg, the vertical furnace tube 100 ). FIG. 6 is a top view of the vertical wafer boat 106 (ie, a view of the top surface of the second plate body 132). The second plate body 132 is located on the top of the vertical wafer boat 106 and is mainly used to stabilize the wafer boat.

In the embodiment of the present invention, the rod body parts (ie, the first carrying rod body 112 , the second carrying rod body 114 , the third carrying rod body 116 , and the supporting rod body 118 ) are disposed on the first plate body 122 and the second plate body 132 , the lower end of each rod body is connected to the first plate body 122 , and the upper end of each rod body is connected to the second plate body 132 . Furthermore, the individual rod systems are arranged parallel to each other and spaced apart from each other along a circular arc. More specifically, the vertical wafer boat 106 has an open side (such as the open side 136 in the top view of FIG. 6 ) for wafers to enter and exit, and the three support rods 112 , 114 , 116 and the support rods 118 are in The semi-circular arc side 138 opposite to the opening side is arranged in parallel spaced apart from each other. In addition, the first and second bearing rods 112 and 114 are located near both ends of the semi-circular arc side, respectively, as shown in FIG. 6 . In one embodiment, the second bearing rod 114 and the third bearing rod 116 are separated by about 45 degrees; the first bearing rod 112 and the supporting rod 118 are separated by about 45 degrees; and the third bearing rod 116 and the supporting rod are separated by about 45 degrees. The bodies 118 are approximately 90 degrees apart, as shown diagrammatically in FIGS. 3 and 6 . Compared with the wafer boat with more supporting rods, the vertical wafer boat according to the present invention can obtain the following advantageous effects by using three supporting rods and one supporting rod: the contact area with the wafer is less. ; And it is more conducive to the balanced support when the wafer is placed on the wafer boat.

By using the vertical wafer boat 106 according to the present invention having an inclined and rough bearing surface, the uniformity of the thin film produced by the reaction on the wafer surface can be improved, and the undesired particles on the wafer can be eliminated. reduce. In a preferred embodiment, the angle between the inclined bearing surface of the groove and the horizontal plane is between 8° and 10°. In another preferred embodiment, the angle between the inclined bearing surface of the groove and the horizontal plane is about 10°. In addition, in a preferred embodiment, the surface roughness (Ra) of the inclined bearing surface of the groove is greater than 10 μm.

In some embodiments, the vertical boat 106 can be made of quartz (eg, GE model, HSQ model quartz). However, it should be understood that the vertical wafer boat 106 may be made of any other suitable material. In addition, in the vertical wafer boat 106, except for the first carrying rod body 112, the second carrying rod body 114, and the third carrying rod body 116, other parts can be processed to have a smooth surface, and can be sharp and/or sharp. Or sharp corners can be processed to make it round.

In some embodiments, the number of grooves provided on each of the first carrier rod body 112 , the second carrier rod body 114 , and the third carrier rod body 116 may be tens to hundreds. In a preferred embodiment, the number of grooves provided on each of the first carrying rod body 112, the second carrying rod body 114, and the third carrying rod body 116 is 170, and the inclination of each groove is 170. The bearing surfaces are parallel to each other and are separated by a predetermined distance (eg, about 5.2 mm apart in one embodiment).

Compared with the conventional wafer boat for vertical furnace tubes (the bearing surface of the groove is a horizontal plane and the surface is smooth), the present invention adopts the vertical wafer boat with the groove with rough inclined surface, so the following advantageous effects can be obtained: When the reaction gas is transported into the vertical furnace tube 100 for diffusion reaction, since there is a small contact area between the vertical wafer boat according to the present invention and the supported wafers, the reaction gas can be uniformly and effectively dispersed in the wafer. The round surface reacts, thereby improving the thickness uniformity of the deposited film; and it can also reduce the generation of particles on the wafer during the process, thereby reducing wafer defects and effectively improving the yield.

Although the foregoing embodiments have been described in detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways to implement the method and apparatus of the present embodiments. Accordingly, the present embodiments should be regarded as illustrative rather than restrictive, and the present embodiments should not be limited to the specific details set forth herein.

It is to be understood that the structures and/or methods described herein are exemplary in nature and that these particular embodiments or examples should not be regarded as limiting as various changes are possible.

The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes and structures, and other features, functions, acts, and/or properties disclosed herein, and any and all equivalents thereof.

100: Vertical furnace tube 102: Outer tube 104: Inner tube 106: Vertical crystal boat 108: Gas injector 110: Gas Supply Department 112: The first bearing rod 114: The second carrying rod 116: The third bearing rod 118: Support rod 120: Pedestal 122: The first board body 132: The second board 136: Open side 138: semicircular arc side 140: Bearing surface 142: Horizontal plane W: Wafer

The described embodiments and their advantages will be more fully understood with reference to the following detailed description taken in conjunction with the accompanying drawings. These drawings are not intended to limit changes in form and detail of the described embodiments that may be made by those skilled in the art without departing from the spirit and scope of the embodiments.

1 is a schematic cross-sectional view of a vertical furnace tube according to an embodiment of the present invention.

FIG. 2 shows a side view of a vertical wafer boat according to an embodiment of the present invention.

FIG. 3 shows a perspective view of a vertical wafer boat according to an embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a rough surface on a trench of a vertical wafer boat according to an embodiment of the present invention.

5 is a bottom view of a vertical wafer boat according to an embodiment of the present invention.

6 is a top view of a vertical wafer boat according to an embodiment of the present invention.

In the drawings of the present invention, reference numerals may be reused to designate similar and/or identical elements.

106: Vertical crystal boat

112: The first bearing rod

114: The second carrying rod

116: The third bearing rod

118: Support rod

122: The first board body

132: The second board

Claims (7)

A vertical crystal boat for vertical furnace tubes, comprising: three support rods, each of which has a plurality of grooves, wherein each of the plurality of grooves has a support surface and a horizontal surface for supporting the wafer; The support rod is used to strengthen the structural strength of the vertical crystal boat; a first plate body located at the bottom of the vertical wafer boat and connected to the lower end of each of the three bearing rod bodies and the support rod body; and a second plate body, located on the top of the vertical wafer boat, and connected to the upper end of each of the three bearing rod bodies and the support rod body, wherein the bearing surfaces of the plurality of grooves on the three bearing rods are roughened and inclined with respect to the horizontal planes, and The vertical wafer boat has an opening side for wafers to enter and exit the vertical wafer boat, and the three supporting rods and the supporting rods are arranged in parallel and spaced apart from each other on the semi-circular arc side opposite to the opening side. , and the first and second carrying rod systems of the three carrying rod bodies are respectively located near the two ends of the semicircular arc side. The vertical crystal boat for vertical furnace tubes as claimed in claim 1, wherein the three supporting rods, the supporting rods, the first plate body, and the second plate system are made of quartz material. The vertical wafer boat for vertical furnace tubes according to claim 1, wherein the bearing surfaces of the plurality of grooves on the three bearing rods have a surface roughness of Ra >10 μm. The vertical crystal boat for vertical furnace tubes according to claim 1, wherein the angle between the bearing surfaces of the plurality of grooves on the three bearing rods and the horizontal planes is about 8°~10° within the range of °. The vertical wafer boat for vertical furnace tubes according to claim 4, wherein the angle between the bearing surfaces of the plurality of grooves on the three bearing rods and the horizontal planes is about 10°. The vertical wafer boat for vertical furnace tubes according to claim 1, wherein the third one of the three carrying rods and the second carrying rod are spaced apart by about 45° on the semicircular arc side, And the support rod body and the first bearing rod body are spaced about 45° on the semicircular arc side. A vertical furnace tube, comprising: an outer tube; an inner tube disposed inside the outer tube; a plurality of gas injectors for delivering one or more reaction gases to the interior of the vertical furnace tube; and The vertical wafer boat according to any one of claims 1 to 6 is disposed inside the inner tube and used for carrying wafers.

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