TWI863070B - Silicon wafer epitaxial growth base support frame and device - Google Patents

Abstract

The present invention provides a silicon wafer epitaxial growth base support frame and device, the base support frame includes: a support column; and, a plurality of support arms extending radially outward and axially upward from the longitudinal axis of the support column, the support arm including a first end and a second end opposite to each other in the axially upward extension direction thereof, the first end being connected to the support column, and the second end supporting a base for carrying a silicon wafer together with the support column; the support arm also includes a middle area between the first end and the second end along the axially upward extension direction thereof, the silicon wafer epitaxial growth base support frame also includes: a plurality of arcuate arms, an arcuate arm being connected between the middle areas of two adjacent support arms, and the plurality of arcuate arms all have the longitudinal axis of the support column as the center and the same radius to form a circular ring shape together. The silicon wafer epitaxial growth base support frame and device provided by the embodiment of the present invention can improve the uniformity of the thickness of the epitaxial layer growth and enhance the flatness of the epitaxial silicon wafer.

Description

Silicon wafer epitaxial growth base support frame and device

The present invention relates to a silicon wafer epitaxial growth technology field, and in particular to a silicon wafer epitaxial growth base support frame and device.

This invention claims priority to Chinese Patent Application No. 202211523610.0 filed in China on November 30, 2022, the entire contents of which are incorporated herein by reference.

The epitaxial growth process of silicon wafers is an important process in the semiconductor chip manufacturing process. This process refers to the process of growing a layer of silicon single crystal layer with controllable resistivity and thickness, no crystal originating particles (COP) defects and no oxygen deposition on a polished silicon wafer under certain conditions. The epitaxial growth of silicon wafers mainly includes vacuum epitaxial deposition, vapor phase epitaxial deposition and liquid phase epitaxial deposition, among which vapor phase epitaxial deposition is the most widely used. In a high temperature environment, silicon source gas reacts with hydrogen to generate single crystal silicon and deposits it on the surface of the silicon wafer to obtain an epitaxial layer. At the same time, a doping agent (B ₂ H ₆ or PH ₃ ) is introduced to dope the epitaxial layer to obtain the required resistivity.

The epitaxial growth device includes a reaction chamber formed by an upper quartz bell jar and a lower quartz bell jar, and a base for carrying a silicon wafer and a base support part for supporting the base are arranged in the reaction chamber. Since the gas enters the chamber in a single direction during the epitaxial growth process, the silicon wafer needs to be rotated during the growth process to ensure uniform growth. Therefore, the base support part can fix the base and drive the base to rotate so that the epitaxial growth can be carried out uniformly on the substrate. Outside the quartz bell jar, a heating bulb is arranged to provide reaction energy, which provides heat for the reaction by thermal radiation.

For epitaxial growth of silicon wafers, flatness is an important indicator to measure the quality of epitaxial silicon wafers, and the flatness of epitaxial silicon wafers is directly related to the thickness of the epitaxial layer. During the epitaxial growth process, the temperature in the reaction chamber generated by the halogen lamp, the concentration of the silicon source gas, the flow rate of the silicon source gas, etc. will have a very obvious impact on the thickness of the epitaxial layer. The uniformity of the epitaxial film thickness is an important part of the quality of epitaxial wafers, and the condition for high-quality epitaxial wafers is that the film thickness distribution on the wafer surface is within a predetermined range.

In the related art, the thickness of the epitaxial film is affected by the temperature of the silicon wafer located below it. The silicon wafer is heated by the susceptor, but the susceptor support part exists below the susceptor. Due to the existence of the susceptor support part, the temperature of the susceptor shielded by the susceptor support part on the heat radiation path is different from the temperature of other parts, resulting in the problem of uneven temperature of the entire susceptor.

The embodiment of the present invention provides a silicon wafer epitaxial growth base support frame and device, which can improve the uniformity of the thickness of the epitaxial layer growth and enhance the flatness of the epitaxial silicon wafer.

The technical solutions provided by the embodiments of the present invention are as follows:

A silicon wafer epitaxial growth base support frame includes: a support column; and a plurality of support arms extending radially outward and axially upward from the longitudinal axis of the support column, the support arm including a first end and a second end opposite to each other in the axially upward extension direction, the first end being connected to the support column, and the second end supporting a base for carrying a silicon wafer together with the support column; the support arm also includes a middle area between the first end and the second end along the axially upward extension direction, the silicon wafer epitaxial growth base support frame also includes: a plurality of arcuate arms, an arcuate arm being connected between the middle areas of two adjacent support arms, and the plurality of arcuate arms all have the longitudinal axis of the support column as the center and the same radius to form a circular ring shape together.

Exemplarily, the arc arm is made of the same material as the support arm.

Exemplarily, the arc arm and the support arm are both made of quartz material.

Exemplarily, the arc-shaped arm and the support arm have the same thickness in the longitudinal axis direction of the support column.

Exemplarily, the width of the arc-shaped arm along its own radial direction ranges from 8 to 12 mm.

Exemplarily, on a projection plane perpendicular to the longitudinal axis of the support column, the orthographic projection of the support arm on the projection plane has a first radius along the radial direction of the support column, and the orthographic projection of the arc arm on the projection plane has a second radius along the radial direction of the support column, and the second radius is equal to half of the first radius.

Exemplarily, there are three support arms, and the three support arms are evenly distributed around the circumference of the support column.

The present invention also provides a silicon wafer epitaxial growth device, which includes: A base for carrying a silicon wafer; A base support frame as described above, the base support frame is located below the base.

Exemplarily, a reaction chamber for accommodating a base includes an upper bell jar and a lower bell jar, the upper bell jar and the lower bell jar together enclose a reaction chamber, the base separates the reaction chamber into an upper reaction chamber and a lower reaction chamber, and the silicon wafer is placed in the upper reaction chamber; A heating element is arranged outside the reaction chamber, and provides a high temperature environment for vapor phase epitaxial deposition for the reaction chamber through the upper bell jar and the lower bell jar; wherein the base support frame is located on the radiation path of the heating element radiating heat to the base.

Exemplarily, the silicon wafer epitaxial growth device further includes: An air inlet, which is arranged on the side wall of the reaction chamber and is used to sequentially transport the cleaning gas and the silicon source gas into the reaction chamber; An exhaust port, which is arranged on the side wall of the reaction chamber and is used to discharge the reaction tail gas of the cleaning gas and the silicon source gas from the reaction chamber.

The beneficial effects brought by the embodiments of the present invention are as follows:

In the above scheme, arc arms are connected between the middle areas of adjacent support arms of the base support frame, so that multiple arc arms between the multiple support arms can form a ring shape. The ring shape can play the role of shielding heat radiation like the support arm, thereby reducing the impact of the arc arm connection area on the epitaxial growth of the silicon wafer and improving the thickness uniformity and flatness of the epitaxial layer.

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be described clearly and completely in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those with ordinary knowledge in the field without the need for progressive improvements are within the scope of protection of the present invention.

Unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary knowledge in the field to which the present invention belongs. "First", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one", "an" or "the" and other similar words do not indicate quantitative limitations, but indicate the existence of at least one. "Include" or "comprising" and other similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to express relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

Before describing in detail the silicon wafer epitaxial growth base support frame and the device provided by the embodiment of the present invention, it is necessary to describe the related technologies as follows:

In the related technology, the silicon wafer epitaxial growth device may include a base, a base support frame and a heating element, wherein the base support frame is supported under the base, and the silicon wafer is loaded onto the base. When the epitaxial layer grows, the base and the base support frame can be rotated to improve the uniformity of the epitaxial layer growth on the surface of the silicon wafer.

The inventor of the present invention has found through research that the thickness of the epitaxial layer on the silicon wafer is affected by the temperature of the base below it, and the base support frame is located below the base and on the heat radiation path of the heating element, which will shield part of the heat of the base, resulting in temperature differences in different areas of the base, which in turn leads to the problem of uneven epitaxial layer.

As shown in Figure 1, an epitaxial layer formed after epitaxial growth of a silicon wafer using a silicon wafer epitaxial growth device in related technology is used as an example. The figure shows the thickness result of the epitaxial layer, and different color levels represent different thicknesses of the epitaxial layer. It can be seen from the figure that there is an annular area A at a certain distance from the center of the silicon wafer. There is a color difference between this area A and other areas. The inventor has found that the reason for the generation of this area is that the support arm affects the distribution of the thermal field, which in turn affects the growth rate of the epitaxial layer, and ultimately leads to differences in the thickness of the epitaxial layer.

In order to solve the above problems, as shown in FIG. 2 and FIG. 3, an embodiment of the present invention provides a silicon wafer epitaxial growth base support frame, comprising: a support column 210; and a plurality of support arms 220 extending radially outward and axially upward from the longitudinal axis of the support column 210, the support arm 220 comprising a first end and a second end opposite to each other in the axially upward extension direction thereof, the first end being connected to the support column 210, and the second end being supported together with the support column 210 for supporting the substrate. The base 100 for carrying silicon wafers; the support arm 220 also includes a middle area 221 located between the first end and the second end along its axial upward extension direction, and the silicon wafer epitaxial growth base support frame also includes: a plurality of arc arms 222, an arc arm 222 is connected between the middle areas 221 of two adjacent support arms 220, and the plurality of arc arms 222 all have the longitudinal axis of the support column 210 as the center and the same radius to form a circular shape together.

In the above scheme, by connecting the arc arms 222 between the middle areas 221 of the adjacent support arms 220 of the base support frame, the multiple arc arms 222 between the multiple support arms 220 can form a ring shape. The ring shape can play the role of shielding heat radiation like the support arm 220, thereby reducing the influence of the area on the support arm 220 connected to the arc arms 222 on the epitaxial growth of the silicon wafer, and improving the thickness uniformity and flatness of the epitaxial layer.

It should be noted here that the connection position between the arc arm 222 and the support arm 220 can be adjusted according to silicon wafers of different sizes, base support frames of different structures, etc. The connection position should be the position corresponding to the annular area with different color levels in the thickness distribution result of the epitaxial layer.

As an exemplary embodiment, the arc arm 222 is made of the same material as the support arm 220. The arc arm 222 and the support arm 220 have the same thickness in the longitudinal axis direction of the support column 210. For example, the arc arm 222 and the support arm 220 can both be made of quartz. In this way, the thermal conductivity of the arc arm 222 and the support arm 220 can be the same as much as possible, so as to have the same impact on the thermal field.

In addition, illustratively, the width of the arc-shaped arm 222 along its own radial direction ranges from 8 to 12 mm. The reason for this setting is that if the width is too small, the influence range of the arc-shaped arm 222 will be too small, and there will still be a temperature uneven area. If the width is too large, it will affect other areas except the annular area shown in FIG. 1, thereby causing the flatness to deteriorate.

In addition, taking a silicon wafer with a diameter of 300 mm as an example, when the silicon wafer is placed in the base 100, due to the shielding of the back support arm 220, the thickness of the silicon wafer epitaxial layer at the half of the silicon wafer radius will be significantly different from that in other areas. The calculation method of the thickness uniformity of the epitaxial layer is: (Max-Min)/(Max+Min), Max represents the maximum thickness value, and Min represents the minimum thickness value. The thickness difference in this area will cause the difference between the Max value and the Min value to become larger, thereby causing the thickness uniformity to deteriorate, and then causing the surface flatness of the silicon wafer to deteriorate.

Therefore, in an exemplary embodiment, on a projection plane perpendicular to the longitudinal axis direction of the support column 210, the orthographic projection of the support arm on the projection plane has a first radius along the radial direction of the support column 210, and the orthographic projection of the arc arm 222 on the projection plane has a second radius along the radial direction of the support column 210, and the second radius is equal to half of the first radius.

It should be noted that in other embodiments, according to different actual silicon wafer sizes and different structures of the support arm 220, the ratio of the second radius to the first radius can also be adaptively adjusted.

In addition, exemplarily, there are three support arms 220, and the three support arms 220 are evenly distributed around the circumference of the support column 210.

In addition, the embodiment of the present invention also provides a silicon wafer epitaxial growth device, which includes: A base 100 for supporting a silicon wafer; A base support frame provided by the embodiment of the present invention, the base support frame is located below the base 100.

Exemplarily, the reaction chamber for accommodating the base 100 includes an upper bell 300 and a lower bell 400, the upper bell 300 and the lower bell 400 together enclose the reaction chamber, the base 100 separates the reaction chamber into an upper reaction chamber and a lower reaction chamber, and the silicon wafer is placed in the upper reaction chamber; The heating element 500 is arranged outside the reaction chamber, and provides a high temperature environment for vapor phase epitaxial deposition for the reaction chamber through the upper bell 300 and the lower bell 400; The base support frame is located on the radiation path of the heating element 500 to radiate heat to the base 100.

Exemplarily, the silicon wafer epitaxial growth device further includes: An air inlet 600, which is disposed on the side wall of the reaction chamber and is used to sequentially transport the cleaning gas and the silicon source gas into the reaction chamber; An exhaust port 700, which is disposed on the side wall of the reaction chamber and is used to discharge the reaction tail gas of the cleaning gas and the silicon source gas from the reaction chamber.

The following points need to be explained: (1) The drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention, and other structures can refer to the general design. (2) For the sake of clarity, in the drawings used to describe the embodiments of the present invention, the thickness of the layer or region is enlarged or reduced, that is, these drawings are not drawn according to the actual scale. It can be understood that when an element such as a layer, film, region or substrate is said to be located "on" or "under" another element, the element can be "directly" located "on" or "under" another element or there can be an intermediate element. (3) In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

The above are only specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the patent application.

100: base 210: support column 220: support arm 221: middle area 222: arc arm 300: upper bell 400: lower bell 500: heating element 600: air inlet 700: exhaust port A: area

Figure 1 shows a schematic diagram of the thickness color gradation of the silicon wafer epitaxial layer in the related technology; Figure 2 shows a schematic diagram of the structure of the silicon wafer epitaxial growth device provided by the embodiment of the present invention; Figure 3 shows a top view of the silicon wafer epitaxial growth base support frame provided by the embodiment of the present invention.

A: Area

Claims (9)

A silicon wafer epitaxial growth base support frame, comprising: a support column; and a plurality of support arms extending radially outward and axially upward from the longitudinal axis of the support column, the support arm comprising a first end and a second end opposite to each other in the axially upward extension direction thereof, the first end being connected to the support column, and the second end supporting a base for carrying a silicon wafer together with the support column; the support arm also comprising a middle region between the first end and the second end in the axially upward extension direction thereof, the silicon wafer epitaxial growth base support frame also comprising : Multiple arc arms, one arc arm is connected between the middle areas of two adjacent support arms, and multiple arc arms are centered on the longitudinal axis of the support column and have the same radius to form a circular ring shape; the connection position between the arc arm and the support arm can be adjusted according to silicon wafers of different sizes, base support frames of different structures, etc., and the connection position is the position corresponding to the annular area with different color levels in the thickness distribution result of the epitaxial layer; the width of the arc arm along its own radial direction ranges from 8 to 12 mm. As described in claim 1, the silicon wafer epitaxial growth base support frame, wherein the arc-shaped arm and the support arm are made of the same material. As described in claim 1, the silicon wafer epitaxial growth base support frame, wherein the arc arm and the support arm are both made of quartz material. As described in claim 1, the silicon wafer epitaxial growth base support frame, wherein the arc-shaped arm and the support arm have the same thickness in the longitudinal axis direction of the support column. As described in claim 1, the silicon wafer epitaxial growth base support frame, wherein, on a projection plane perpendicular to the longitudinal axis direction of the support column, the orthographic projection of the support arm on the projection plane has a first radius along the radial direction of the support column, and the orthographic projection of the arc-shaped arm on the projection plane has a second radius along the radial direction of the support column, and the second radius is equal to half of the first radius. As described in claim 1, the silicon wafer epitaxial growth base support frame, wherein the number of the support arms is three, and the three support arms are evenly distributed around the circumference of the support column. A silicon wafer epitaxial growth device, the device comprising: a base for carrying a silicon wafer; a silicon wafer epitaxial growth base support frame as described in any one of claims 1 to 6, the silicon wafer epitaxial growth base support frame is located below the base. The silicon wafer epitaxial growth device as described in claim 7, wherein the reaction chamber for accommodating the base includes an upper bell jar and a lower bell jar, the upper bell jar and the lower bell jar together enclose the reaction chamber, the base separates the reaction chamber into an upper reaction chamber and a lower reaction chamber, and the silicon wafer is placed in the upper reaction chamber; a heating element, which is arranged outside the reaction chamber and provides a high temperature environment for vapor phase epitaxial deposition for the reaction chamber through the upper bell jar and the lower bell jar; wherein the base support frame is located on the radiation path of the heating element radiating heat to the base. As described in claim 8, the silicon wafer epitaxial growth device further includes: an air inlet, which is arranged on the side wall of the reaction chamber and is used to sequentially transport the cleaning gas and the silicon source gas into the reaction chamber; an exhaust port, which is arranged on the side wall of the reaction chamber and is used to discharge the reaction tail gas of the cleaning gas and the silicon source gas from the reaction chamber.