Wafer heat treatment device

Abstract

The invention provides a wafer heat treatment device which comprises a reaction cavity and a carrying table, and a through hole used for containing an ejector pin is formed in the carrying table; the reaction cavity is provided with a first air inlet and a second air inlet which are located on the same side, the first air inlet is higher than the carrying table, and the second air inlet is lower than the carrying table. In the technological process, a first air flow is conveyed to the position above a carrying table through a first air inlet, a second air flow is conveyed to the position below the carrying table through a second air inlet, the flow velocity relational expression of the first air flow and the second air flow is calculated according to the Bernoulli principle, and then the sizes of the first air inlet and the second air inlet are designed according to the relational expression. The particles accumulated in the through holes can be taken away by the second airflow, so that the reaction cavity is kept clean. When the device provided by the invention is used for carrying out heat treatment on the wafer, particles in the through hole of the carrying table can be cleaned in the technological process, so that the cleaning cost is saved, and the production efficiency is improved; in addition, the defects of the wafer caused by the particles can be avoided, and the quality and the yield of the chip are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor manufacturing, and specifically relates to a wafer heat treatment device. Background Art

[0002] In Situ Steam Generation (ISSG) is a technology widely used in the field of semiconductor manufacturing, especially in the shallow trench isolation sidewall oxidation and gate oxide processes at process nodes of 55nm and below. This process can provide a precise oxide layer, which is crucial to improving chip performance and reliability.

[0003] In the reaction chamber used for the in-situ steam oxidation process, the wafer is placed on a carrier with a through hole for accommodating the ejector pin. During the process, the high flow gas in the reaction chamber will cause the Bernoulli effect, causing the byproducts produced in the process to accumulate in the through hole, forming a potential source of particles. These particles may be brought into the reaction chamber due to the pressure difference generated by the airflow, and eventually scattered on the surface of the wafer, forming defects on the surface of the wafer, affecting the quality and yield of the chip. In order to solve this problem, the existing technology generally takes measures to clean the through hole regularly, which can reduce the defects caused by these particles to a certain extent. However, this method cannot solve the particle problem that already exists in the pretreatment stage. In addition, this method is not conducive to improving production efficiency. Summary of the invention

[0004] In view of the shortcomings of the prior art described above, the present invention provides a wafer heat treatment device, including a reaction chamber and a carrier, wherein the wafer is placed on the carrier, and the carrier has a through hole for accommodating a pin; the reaction chamber has a first air inlet and a second air inlet located on the same side, wherein the first air inlet is arranged higher than the carrier, and the second air inlet is arranged lower than the carrier. During the process, the first air inlet conveys the first air flow to the top of the carrier, and the second air inlet conveys the second air flow to the bottom of the carrier, and the flow velocity relationship between the first air flow and the second air flow is calculated in combination with the Bernoulli principle, and then the size of the first air inlet and the second air inlet is designed according to the relationship, so that the particles accumulated in the through hole can be taken away by the second air flow, thereby keeping the reaction chamber clean. By using the device provided by the present invention to heat treat the wafer, the particles in the through hole of the carrier can be cleaned during the process, which saves the cleaning cost and improves the production efficiency; in addition, the defects caused by the particles to the wafer can be avoided, and the quality and yield of the chip can be effectively improved.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides a wafer heat treatment device, including a reaction chamber and a carrier, wherein:

[0006] The carrier is located in the reaction chamber and is used to place the wafer;

[0007] The reaction chamber has a first air inlet and a second air inlet located on the same side, the first air inlet is arranged above the stage, and the second air inlet is arranged below the stage;

[0008] The reaction chamber further comprises a first gas outlet and a second gas outlet located on the same side, and the first gas outlet / the second gas outlet are arranged opposite to the first gas inlet / the second gas inlet;

[0009] A first airflow is formed between the first air inlet and the first air outlet, and a second airflow is formed between the second air inlet and the second air outlet.

[0010] Optionally, the air pressure generated by the second airflow is lower than the air pressure generated by the first airflow.

[0011] Optionally, the first air outlet is arranged at the same height as the first air inlet.

[0012] Optionally, the second air outlet is arranged at the same height as the second air inlet.

[0013] Optionally, the second air outlet is arranged lower than the second air inlet.

[0014] Optionally, the flow rates of the first airflow and the second airflow are equal.

[0015] Optionally, a flow controller is further included, which is located outside the reaction chamber and is used to supply gas to the first gas inlet and the second gas inlet.

[0016] Optionally, the flow controller is connected to the first air inlet through a first pipeline, and the cross-sectional area of ​​the first pipeline is equal to that of the first air inlet.

[0017] Optionally, the flow controller is connected to the second air inlet through a second pipeline, and the cross-sectional area of ​​the second pipeline is equal to that of the second air inlet.

[0018] Optionally, the carrier has a plurality of evenly distributed through holes, and the through holes penetrate the upper surface and the lower surface of the carrier.

[0019] The wafer heat treatment device provided by the present invention has at least the following beneficial effects:

[0020] 1) The device provided by the present invention is used to perform heat treatment on the wafer, a first airflow is generated above the carrier, and a second airflow is generated below the carrier. The pressure difference between the first airflow and the second airflow is used to make the second airflow take away the particles accumulated in the through hole, thereby preventing the particles from causing defects to the wafer, and effectively improving the quality and yield of the chip;

[0021] 2) By utilizing the pressure difference between the first airflow and the second airflow, particulate matter in the through hole of the carrier can be cleaned during the process, saving cleaning costs and effectively improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a schematic structural diagram of a wafer heat treatment device provided in an embodiment.

[0023] Component number description

[0024] 1 Reaction chamber

[0025] 101 First air intake

[0026] 102 Second air inlet

[0027] 103 First air outlet

[0028] 104 Second air outlet

[0029] 2. Carrier

[0030] 200 Through hole

[0031] 3 Flow controller

[0032] 4 First pipeline

[0033] 5 Second pipeline

[0034] 6 Vacuum pump DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0036] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Although the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation, the form, quantity, positional relationship and proportion of each component in actual implementation can be changed at will under the premise of realizing the technical solution of this party, and the component layout form may also be more complicated.

[0037] Example

[0038] According to Bernoulli's principle, when gas flows in a chamber, the pressure is low where the flow rate is fast, and high where the flow rate is slow. In combination with a wafer heat treatment device, when gas flows in a reaction chamber, due to the complexity of the internal structure of the device, there will be local flow rate differences. For example, if there is a small protrusion or narrow channel in the device, the gas will flow faster when flowing through this area, and the surrounding area with lower pressure may attract nearby particles. This is because there is a pressure difference between the normal pressure area and the low pressure area. Driven by this pressure difference, the particles will move to the low pressure (high flow rate) area, causing particle accumulation.

[0039] This embodiment provides a wafer heat treatment device, such as Figure 1 As shown, it includes a reaction chamber 1 , a carrier 2 and a flow controller 3 . The carrier 2 is located in the reaction chamber 1 and is used to place wafers. The flow controller 3 is used to supply gas to the reaction chamber 1 .

[0040] As an example, the shape, material and size of the reaction chamber 1 can be selected and adjusted as needed, without specific limitation herein, as long as the heat treatment requirements of the wafer to be processed can be met; the internal structure and size of the reaction chamber 1 can also be selected and adjusted according to the requirements of the wafer to be processed, as long as the wafer can be placed therein and heat treated.

[0041] like Figure 1 As shown, the carrier 2 has a plurality of evenly distributed through holes 200, which penetrate the upper and lower surfaces of the carrier 2. The through holes 200 are used to accommodate ejector pins (not shown in the figure). During the process, the ejector pins are used to lift the wafer. As an example, the number of ejector pins is at least three, that is, the number of through holes 200 is at least three. The more ejector pins there are, the more stable the wafer can be lifted and supported. In this embodiment, the number of ejector pins is three, that is, there are three through holes 200 on the carrier 2, and the three through holes 200 are arranged in an equilateral triangle on the carrier 2. In other optional embodiments, the number of ejector pins can be more, as long as it can ensure that the wafer is lifted and prevented from sliding.

[0042] As an example, the carrier 2 can be made of aluminum, and the surface of the carrier 2 is anodized to form a thin layer of aluminum oxide. The thin layer of aluminum oxide can improve the hardness and wear resistance of the carrier 2, optimize the heat resistance of the carrier 2, and enhance the corrosion resistance of the carrier 2, so as to ensure the reliability and durability of the carrier 2 in the working environment.

[0043] like Figure 1As shown, the flow controller 3 is located outside the reaction chamber 1, and is used to provide the reaction gas to the reaction chamber 1. As an example, the type of reaction gas, flow rate and other parameters are determined according to the type of heat treatment. In this embodiment, the in situ steam generation (ISSG) process is taken as an example, and the reaction gas is a mixed gas of nitrogen, oxygen, hydrogen and nitrous oxide, and the flow rate of the reaction gas is between 15 and 25 slm (standard liters per minute), preferably 20 slm.

[0044] like Figure 1 As shown, the reaction chamber 1 has a first gas inlet 101, a second gas inlet 102, a first gas outlet 103 and a second gas outlet 104, wherein the first gas inlet 101 and the second gas inlet 102 are located on the same side, and the first gas outlet 103 and the second gas outlet 104 are located on the other opposite side.

[0045] As an example, the first gas inlet 101 and the first gas outlet 103 are located at the same height and are higher than the carrier 2. The flow controller 3 delivers the reaction gas into the reaction chamber 1 through the first gas inlet 101, and controls the flow rate of the reaction gas within a set range, generates a first gas flow above the carrier 2, and the reacted gas flows out of the reaction chamber 1 through the first gas outlet 103. In this embodiment, the flow rate V1 of the gas (i.e., the first gas flow) flowing into the reaction chamber 1 from the first gas inlet 101 is 20 slm (standard liters per minute).

[0046] As an example, the flow controller 3 is connected to the first air inlet 101 through the first pipeline 4. The cross-sectional areas of the first pipeline 4 and the first air inlet 101 are equal, both are S1. In this embodiment, the diameter of the first pipeline 4 is 1 / 4 inch (about 6.35 mm).

[0047] As an example, the second gas inlet 102 is arranged below the stage 2, and the second gas outlet 104 can be located at the same height as the second gas inlet 102, or can be arranged below the second gas inlet 102. In this embodiment, the second gas outlet 104 is located at the same height as the second gas inlet 102. The flow controller 3 delivers the reaction gas into the reaction chamber 1 through the second gas inlet 102, generates a second gas flow at the bottom of the stage 2, and the second gas flow flows out of the reaction chamber 1 through the second gas outlet 104.

[0048] As an example, the flow controller 3 is connected to the second air inlet 102 through the second pipeline 5, and the cross-sectional area of ​​the second pipeline 5 and the second air inlet 102 are equal, both being S2.

[0049] As an example, the first gas outlet 103 and the second gas outlet 104 are both connected to the vacuum pump 6. The vacuum pump 6 can adopt any pump structure in the prior art, and is not specifically limited here, as long as it can achieve the purpose of sucking the gas in the reaction chamber 1. On the one hand, the vacuum pump 6 is used to discharge the reacted gas from the reaction chamber 1. On the other hand, the vacuum pump 6 can also form a first airflow flowing in the horizontal direction above the carrier 2 and a second airflow flowing in the horizontal direction at the bottom of the carrier 2 by sucking the gas in the reaction chamber 1. By controlling the flow rate V2 of the second airflow, the air pressure generated by it can balance the pressure in the reaction chamber 1, thereby eliminating the turbulence caused by Bernoulli's principle, so that the particles accumulated in the through hole 200 are taken away by the second airflow, so that the reaction chamber 1 is kept clean. Specifically, according to Bernoulli's principle, formula (1) is obtained:

[0050]

[0051] Wherein, P1 is the air pressure generated by the first airflow, P2 is the air pressure generated by the second airflow, V1 is the flow rate of the first airflow, V2 is the flow rate of the second airflow, h1 is the height of the first airflow, h2 is the height of the second airflow, ρ is the density of the reaction gas, and g is the gravitational acceleration. To achieve the effect of eliminating turbulence, it is necessary to make the air pressure P2 generated by the second airflow less than the air pressure P1 generated by the first airflow, that is, P2-P1<0. Combining formula (1), we get formula (2):

[0052]

[0053] Wherein, Δh is the difference between the first airflow height h1 and the second airflow height h2, that is, the height difference between the first air inlet 101 and the second air inlet 102. In addition, according to the continuity equation of the fluid, formula (3) is obtained:

[0054] S1×V1=S2×V2 (3)

[0055] Wherein, S1 is the cross-sectional area of ​​the first gas flow, that is, the cross-sectional area of ​​the first pipeline 4, S2 is the cross-sectional area of ​​the second gas flow, that is, the cross-sectional area of ​​the second pipeline 4, V1 is the flow rate of the first gas flow, and V2 is the flow rate of the second gas flow. Therefore, by combining formula (2) and formula (3), the cross-sectional area S2 of the second pipeline 5 can be calculated, so that the second gas flow output by the second pipeline 5 can carry away the particles accumulated in the through hole 200, thereby achieving the effect of cleaning the reaction chamber 1.

[0056] In this embodiment, the flow rate V1 of the first air flow is 20 slm (standard liters per minute), and the height difference Δh between the first air inlet 101 and the second air inlet 102 is 0.2 m. According to formula (2), it can be calculated that the flow rate V2 of the second air flow needs to be greater than 20.1 slm (standard liters per minute). Furthermore, the diameter of the first pipeline 4 is 1 / 4 inch (about 6.35 mm). According to formula (3), it can be calculated that the radius of the second pipeline 5 is approximately less than 3.115 mm, so that the second air flow can carry away the particles accumulated in the through hole 200, so that the reaction chamber 1 can be kept clean.

[0057] The wafer heat treatment device provided in this embodiment includes a reaction chamber and a carrier, the wafer is placed on the carrier, and the carrier has a through hole for accommodating a pin; the reaction chamber has a first air inlet and a second air inlet located on the same side, the first air inlet is arranged higher than the carrier, and the second air inlet is arranged lower than the carrier. During the process, the first air inlet conveys the first air flow to the top of the carrier, and the second air inlet conveys the second air flow to the bottom of the carrier. The flow velocity relationship between the first air flow and the second air flow is calculated in combination with the Bernoulli principle, and then the size of the first air inlet and the second air inlet is designed according to the relationship, so that the particles accumulated in the through hole can be taken away by the second air flow, so that the reaction chamber is kept clean. By using the device provided in this embodiment to heat treat the wafer, the particles in the through hole of the carrier can be cleaned during the process, saving the cleaning cost and improving the production efficiency; in addition, it can also avoid the defects caused by particles to the wafer, effectively improving the quality and yield of the chip.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A wafer heat treatment device, characterized in that: It includes a reaction chamber and a carrier, wherein: The carrier is located in the reaction chamber and is used to place the wafer; The reaction chamber has a first air inlet and a second air inlet located on the same side, the first air inlet is arranged above the stage, and the second air inlet is arranged below the stage; The reaction chamber further comprises a first gas outlet and a second gas outlet located on the same side, and the first gas outlet / the second gas outlet are arranged opposite to the first gas inlet / the second gas inlet; A first airflow is formed between the first air inlet and the first air outlet, and a second airflow is formed between the second air inlet and the second air outlet.

2. The wafer heat treatment device according to claim 1, characterized in that: The air pressure generated by the second airflow is lower than the air pressure generated by the first airflow.

3. The wafer heat treatment device according to claim 2, characterized in that: The first air outlet is arranged at the same height as the first air inlet.

4. The wafer heat treatment device according to claim 2, characterized in that: The second air outlet is arranged at the same height as the second air inlet.

5. The wafer heat treatment device according to claim 2, characterized in that: The second air outlet is arranged lower than the second air inlet.

6. The wafer heat treatment device according to claim 1, characterized in that: The flow rates of the first airflow and the second airflow are equal.

7. The wafer heat treatment device according to claim 1, characterized in that: It also includes a flow controller, which is located outside the reaction chamber and is used to supply gas to the first gas inlet and the second gas inlet.

8. The wafer heat treatment device according to claim 7, characterized in that: The flow controller is connected to the first air inlet through a first pipeline, and the cross-sectional area of ​​the first pipeline is equal to that of the first air inlet.

9. The wafer heat treatment device according to claim 7, characterized in that: The flow controller is communicated with the second air inlet through a second pipeline, and the cross-sectional area of ​​the second pipeline is equal to that of the second air inlet.

10. The wafer heat treatment device according to claim 1, characterized in that: The carrier is provided with a plurality of evenly distributed through holes, and the through holes penetrate the upper surface and the lower surface of the carrier.

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