Tray assembly and chemical vapor deposition apparatus

Abstract

This invention provides a tray assembly and a chemical vapor deposition apparatus. The tray assembly includes: a tray for supporting a substrate, the lower surface of which has cold areas with uneven heating during the process; a light guide disposed below the tray; and an auxiliary radiant heat source, the emitted light being incident from one end of the light guide, transmitted forward by total internal reflection within the light guide, and projected from the other end of the light guide onto the cold areas of the tray, thereby heating the cold areas. This invention is used to eliminate localized cold areas on the tray and improve the uniformity of thin film deposition on the substrate surface.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and in particular to a tray assembly and a chemical vapor deposition apparatus. Prior Technology

[0002] In the semiconductor device manufacturing process, a large number of micro-processes are required. Common methods include vapor deposition (PVD) or plasma processing, which utilize the principle of a vacuum reaction chamber to process semiconductor substrates. Based on whether the thin film deposition process involves a chemical reaction, thin film vapor deposition can be divided into physical vapor deposition (PVD) and chemical vapor deposition (CVD). CVD is currently the most widely used technology in the semiconductor industry for depositing a wide range of materials, including a broad range of insulating materials, most metals, and metal alloys.

[0003] During thin film deposition, uneven distribution of heating temperature field on the substrate can affect the uniformity of thin film deposition on the substrate surface. This can lead to defects such as uneven thickness, uneven composition, and uneven physical properties of the deposited film on the substrate surface, thereby reducing the yield of substrate production.

[0004] Existing chemical vapor deposition (CVD) apparatuses typically place a radiant heat source outside the chamber to heat the tray and substrate inside the chamber by emitting infrared radiation. However, during the process, due to the influence of airflow or tray structure, the temperature in some areas of the tray is significantly lower than that in other areas, resulting in localized cold zones and uneven film deposition on the substrate surface. Summary of the Invention

[0005] The purpose of this invention is to provide a tray assembly and a chemical vapor deposition apparatus to eliminate local cold zones on the tray and improve the uniformity of thin film deposition on the substrate surface.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A tray assembly for use in a chemical vapor deposition apparatus, comprising: A tray is used to support the substrate, and the lower surface of the tray has cold areas due to uneven heating during the process; A light guide is disposed below the tray; An auxiliary radiant heat source emits radiant light that enters from one end of the light guide, is transmitted forward by total internal reflection inside the light guide, and is projected from the other end of the light guide onto the cold area of ​​the tray to heat the cold area.

[0008] Optionally, the tray is made of graphite.

[0009] Optionally, the light guide is made of transparent quartz.

[0010] Optionally, the wavelength of the radiation emitted by the auxiliary radiant heat source is less than 3 μm.

[0011] Optionally, the light guide includes a main trunk and several branches extending upward from the main trunk and toward the cold zone, and the auxiliary radiant heat source is located below the main trunk.

[0012] Optionally, the light guide includes several separately arranged branches, each branch facing the cold zone, and an auxiliary radiant heat source is arranged below each branch.

[0013] Optionally, the location of the cold zone includes the edge of the tray.

[0014] Optionally, the plurality of branches are used to support the tray, and the location of the cold zone includes the contact area between the tray and the branches.

[0015] Optionally, the main trunk and the auxiliary radiant heat source are connected to a rotating mechanism, which drives the main trunk to rotate.

[0016] Optionally, all of the branches are fixed in place.

[0017] Optionally, multiple reflective surfaces are provided at the junction of the top of the main trunk and the branch, and the multiple reflective surfaces sequentially reflect the radiated light to the branch.

[0018] Optionally, the auxiliary radiant heat source is an LED lamp, a halogen lamp, or a laser.

[0019] A chemical vapor deposition apparatus, comprising: reaction chamber; The tray assembly as described in any of the preceding descriptions is located within the reaction chamber; Multiple radiant heat sources are disposed on the outside of the reaction chamber to heat the tray and the substrate through the outer wall of the reaction chamber.

[0020] Optionally, the reaction chamber includes an upper cover and a lower cover that are permeable to thermal radiation, and the plurality of radiative heat sources are disposed on the outside of the upper cover and the outside of the lower cover.

[0021] Optionally, the upper cover and the lower cover are made of transparent quartz material.

[0022] Optionally, the sidewall of the reaction chamber is provided with an air inlet and an air outlet for the input and output of process gases.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The present invention provides a light guide and an auxiliary radiant heat source below the tray. The radiant light emitted by the auxiliary radiant heat source propagates inside the light guide in the manner of total internal reflection and is projected onto the cold area on the tray, supplementing the cold area with additional radiant energy, increasing the temperature of the cold area, eliminating local cold areas on the tray, and improving the uniformity of thin film deposition on the substrate surface. Simple Explanation of the Diagram

[0025] Figure 1 is a structural diagram of an existing chemical vapor deposition apparatus; Figure 2 is a schematic diagram of the reflection and refraction of radiated light from the heat source by the supporting column; Figure 3 is a structural diagram of a chemical vapor deposition apparatus according to an embodiment of the present invention; Figure 4 is a structural diagram of a tray assembly provided in another embodiment of the present invention; Figure 5 is a schematic diagram of total internal reflection of the radiated light from the auxiliary radiant heat source by the light guide; Figures 6 to 8 are structural diagrams of a tray assembly provided in other embodiments of the present invention. Implementation

[0026] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the proposed solution of this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to aid those skilled in the art, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0027] Figure 1 shows a structural diagram of a conventional chemical vapor deposition (CVD) apparatus. The apparatus includes a reaction chamber 100, within which is a tray 110 for supporting a substrate. The tray 110 is supported by multiple support columns 120 and is rotatable circumferentially. The tray 110 is typically made of graphite, and the support columns 120 are typically made of transparent quartz. Multiple heat sources 130 are located on the outer side of the reaction chamber 100, radiating infrared light through the outer wall of the reaction chamber 100 to the tray 110 and the substrate.

[0028] Other components in the reaction chamber 100 besides the tray 110, or the shape of the outer shell of the reaction chamber 100, may obstruct the radiation path of the heat source. In addition, the structure in contact with the tray 110 will have a difference in heat conduction with the non-contact area. All of the above reasons lead to cold areas on the upper and lower surfaces of the tray 110 during the process, that is, the surface of the tray 110 will have uneven temperature. This uneven temperature will affect the uneven heating of the substrate carried on it, resulting in defects in thin film deposition.

[0029] In some embodiments, the cold zone originates from the contact area between the support column 120 and the lower surface of the tray 110. Since the quartz support column 120 is transparent, most of the infrared radiation passes through it and is not absorbed. Conversely, the graphite tray 110 is opaque and absorbs most of the infrared radiation. This results in a temperature difference between the tray 110 and the support column 120. Furthermore, heat conduction occurs in the contact area between the tray 110 and the support column 120, causing the temperature of this contact area on the lower surface of the tray 110 to be significantly lower than other areas on the lower surface of the tray 110. Additionally, according to Fresnel's law, the refractive index of transparent quartz is greater than that of a vacuum or atmospheric environment. This means that the support column 120 refracts and reflects the radiated light, as shown in Figure 2. This causes most of the radiated light that should have irradiated the contact area between the support column 120 and the tray 110 to be reflected by the inner and outer surfaces of the support column 120, affecting the uniformity of the projected radiated energy. This also results in the contact area not being adequately irradiated by infrared radiation, exacerbating the temperature difference in this area. Therefore, a localized cold zone is formed in the contact area between the tray 110 and the support column 120.

[0030] In some embodiments, as shown in FIG1, the sidewall of the reaction chamber 100 is provided with an air inlet 140 and an air outlet 150 for the input and discharge of process gas. The flow direction of the process gas in the reaction chamber 100 is approximately parallel to the upper surface of the tray 110. When the airflow passes over the upper surface of the tray 110, it carries away the heat of the tray, especially the heat at the edge of the tray 110, which is more easily carried away by the airflow. This results in the temperature at the edge of the tray 110 being lower than the temperature at the center, thus forming a local cold zone at the edge of the tray 110.

[0031] In view of this, in order to eliminate local cold spots on the tray and improve the uniformity of thin film deposition on the substrate surface, the present invention provides a light guide and an auxiliary radiant heat source below the tray. The radiant light emitted by the auxiliary radiant heat source propagates inside the light guide in the manner of total internal reflection and is projected onto the cold spots on the tray, supplementing the cold spots with additional radiant energy, increasing the temperature of the cold spots, and making the temperature of the tray surface more uniform.

[0032] Specifically, as shown in Figure 3, a chemical vapor deposition apparatus according to an embodiment of the present invention includes a reaction chamber 100. A tray assembly is provided within the reaction chamber 100. The tray assembly includes a tray 110 for supporting a substrate. Multiple radiant heat sources 130 are provided on the outer side of the reaction chamber 100 for heating the tray 110 and the substrate through the outer wall of the reaction chamber 100. The side wall of the reaction chamber 100 has an inlet and an outlet for process gases. The reaction chamber 100 includes an upper cover 100a and a lower cover 100b that are permeable to thermal radiation. The multiple radiant heat sources 130 are located on the outer sides of the upper cover 100a and the lower cover 100b. The upper cover 100a and the lower cover 100b are typically made of transparent quartz material, capable of transmitting most short-wave infrared radiation, thus providing the main energy to the tray 110 and the substrate for heating.

[0033] The tray assembly includes a tray 110, a light guide 111, and an auxiliary radiant heat source 112. As previously mentioned, the lower surface of the tray 110 has cold areas with uneven heating during the process. The light guide 111 is located below the tray 110. The radiant light emitted by the auxiliary radiant heat source 112 enters from one end of the light guide 111 and is transmitted forward by total internal reflection inside the light guide 111. It is then projected from the other end of the light guide 111 onto the cold area of ​​the tray 110, heating the cold area and increasing its temperature. This eliminates the localized cold areas on the tray 110 and improves the uniformity of thin film deposition on the substrate surface. The light guide 111 is designed with dimensions that allow the radiant light to undergo total internal reflection, and its end, where the radiant light exits, faces the cold area. This guides the heat energy from the auxiliary radiant heat source 112, located a distance from the tray 110, to the cold area to achieve temperature compensation.

[0034] In some embodiments, the light guide 111 may be made of transparent quartz to improve the transmission efficiency of the radiated light within the light guide 111. Furthermore, quartz material is less prone to introducing impurities into semiconductor devices.

[0035] In one embodiment, as shown in FIG3, the light guide 111 includes a main trunk 1111 and a plurality of branches 1112 extending upward from the main trunk 1111 and toward the cold zone. The auxiliary radiant heat source 112 is located below the main trunk 1111, thereby heating the cold zone can be achieved by setting only one auxiliary radiant heat source 112.

[0036] The plurality of branches 1112 are used to support the tray 110, and the location of the cold zone includes the contact area between the tray 110 and the branches 1112.

[0037] Furthermore, the main trunk 1111 and the auxiliary radiant heat source 112 are connected to a rotating mechanism. The rotating mechanism is used to drive the main trunk 1111 to rotate, thereby driving the tray 110 to rotate. During the rotation of the tray 110, the radiant light is always directed towards the contact area between the branch 1112 and the tray 110 to heat the cold area.

[0038] In the above embodiments, the light guide 111 also serves as a support for the tray 110. The end of the light guide 111 may not contact the bottom of the tray 110, but only face the cold area at the bottom of the tray 110. The location of the cold area may include the edge of the tray 110, and the plurality of branches 1112 face the edge of the tray 110. Optionally, the plurality of branches 1112 are evenly distributed along the edge of the tray 110 to achieve uniform heating of the edge. In other embodiments, the plurality of branches 1112 may be divided into two parts. One part of the branches 1112 heats the edge cold area from the main branch 1111 towards the edge of the tray 110, and the other part of the branches 1112 acts as a support column in contact with the tray 110, and can heat the cold area of ​​the contact area.

[0039] Furthermore, the main trunk 1111 and the auxiliary radiant heat source 112 are connected to a rotating mechanism. The rotating mechanism is used to drive the main trunk 1111 to rotate, thereby driving the several branches 1112 to rotate, which can improve the heating uniformity of the edge of the tray 110.

[0040] As shown in Figure 5, to achieve total internal reflection of the radiated light to each branch 1112, multiple reflecting surfaces a are provided at the junction of the top of the main trunk 1111 and the branch 1112. These reflecting surfaces a sequentially reflect the radiated light completely before it enters the branch 1112. As shown in Figure 5, the radiated light emitted from the auxiliary radiant heat source 112 enters the main trunk 1111 perpendicularly or substantially perpendicularly, undergoes total internal reflection at the reflecting surface a, and then enters the branch 1112. According to Fresnel's theorem, when light propagates within quartz material, based on the refractive index n=1.45, total internal reflection occurs when the angle between the light ray and the reflecting surface a is less than 47°. Therefore, the reflecting surface a must satisfy the total internal reflection condition to maximize the projection of the radiated light onto the cold area.

[0041] In another embodiment, as shown in Figures 6 to 8, the light guide 111 includes several separately arranged branches 1112, each branch 1112 facing the cold area, and an auxiliary radiant heat source 112 is arranged below each branch 1112.

[0042] As shown in Figure 6, the location of the cold zone includes the edge of the tray 110, and the plurality of branches 1112 face the edge of the tray 110. Optionally, the plurality of branches are evenly distributed along the edge of the tray 110 to uniformly heat the edge cold zone. Furthermore, the plurality of branches 1112 are fixed in place, and when the tray 110 rotates, the heating uniformity of the edge of the tray 110 can be improved.

[0043] As shown in Figure 7, the plurality of branches 1112 are used to support the tray 110, and the location of the cold zone includes the contact area between the tray 110 and the branches 1112. Furthermore, the plurality of branches 1112 are fixed in place to accommodate the requirement that the tray 110 remains stationary in some processes. In addition, the plurality of branches 1112 can be supported on the edge of the tray 110 to simultaneously heat the edge cold zone. Alternatively, as shown in Figure 8, the plurality of branches 1112 are supported on the non-edge area of ​​the tray 110. In this case, extensions 1113 facing the edge of the tray 110 can be provided on the plurality of branches 1112, whereby radiant light can be emitted from the extensions 1113 to heat the edge cold zone.

[0044] The auxiliary radiant heat source 112 can be an LED lamp, a halogen lamp, or a laser, and the wavelength of the emitted radiation light is concentrated below 3μm to ensure that the radiation light emitted by the auxiliary radiant heat source 112 is absorbed by the light guide 111 as little as possible, and the radiation light is incident perpendicularly to the bottom surface of the light guide 111 as much as possible to ensure the lowest reflectivity. In addition, the energy of the radiation light emitted by the auxiliary radiant heat source 112 is adjustable to meet the temperature control requirements of the cold zone in different process scenarios.

[0045] In summary, the present invention provides a light guide and an auxiliary radiant heat source below the tray. The radiant light emitted by the auxiliary radiant heat source propagates inside the light guide in a total internal reflection manner and is projected onto the cold area on the tray. The present invention utilizes the principle of total internal reflection of radiant light on the inner surface of the light guide to supplement the cold area with additional radiant energy, increase the temperature of the cold area, eliminate local cold areas on the tray, and improve the uniformity of thin film deposition on the substrate surface.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0048] 100: Reaction Chamber 100a: Top cover 100b: Bottom Cover 110: Pallet 111: Light guide 1111: Main trunk 1112: Branch a: Reflective surface 112: Auxiliary radiant heat source 120: Support column 130: Radiant heat source 140: Air Intake 150: Air outlet

Claims

1. A tray assembly for use in a chemical vapor deposition apparatus, the tray assembly comprising: A tray for supporting the substrate, the lower surface of which has cold areas with uneven heating during the process; A light guide is disposed below the tray; An auxiliary radiant heat source emits radiant light that enters from one end of the light guide, is transmitted forward by total internal reflection inside the light guide, and is projected from the other end of the light guide onto the cold area of ​​the tray to heat the cold area.

2. The tray assembly as described in claim 1, wherein, The tray is made of graphite.

3. The tray assembly as described in claim 1, wherein, The light guide is made of transparent quartz.

4. The tray assembly as described in claim 1, wherein, The wavelength of the radiation emitted by the auxiliary radiative heat source is less than 3 μm.

5. The tray assembly as described in claim 1, wherein, The light guide includes a main trunk and several branches extending upward from the main trunk toward the cold zone, and the auxiliary radiant heat source is located below the main trunk.

6. The tray assembly as described in claim 1, wherein, The light guide includes several separately arranged branches, each branch facing the cold zone, and an auxiliary radiant heat source is arranged below each branch.

7. The tray assembly as described in claim 5 or 6, wherein, The location of the cold zone includes the edge of the tray.

8. The tray assembly as described in claim 5 or 6, wherein, The plurality of branches are used to support the tray, and the location of the cold zone includes the contact area between the tray and the branches.

9. The tray assembly as described in claim 5, wherein, The main trunk and the auxiliary radiant heat source are connected to a rotating mechanism, which drives the main trunk to rotate.

10. The tray assembly as described in claim 6, wherein, All of the branches are fixed in place.

11. The tray assembly as described in claim 5, wherein, Multiple reflective surfaces are provided at the junction of the top of the main trunk and the branch. The multiple reflective surfaces sequentially reflect the radiated light completely before it is incident on the branch.

12. The tray assembly as claimed in claim 1, wherein, The auxiliary radiant heat source is an LED lamp, a halogen lamp, or a laser.

13. A chemical vapor deposition apparatus, comprising: reaction chamber; The tray assembly as described in any one of claims 1 to 12 is located within the reaction chamber; Multiple radiant heat sources are disposed on the outside of the reaction chamber to heat the tray and the substrate through the outer wall of the reaction chamber.

14. The chemical vapor deposition apparatus as claimed in claim 13, wherein, The reaction chamber includes an upper cover and a lower cover that are permeable to thermal radiation, and the plurality of radiant heat sources are disposed on the outside of the upper cover and the outside of the lower cover.

15. The chemical vapor deposition apparatus as claimed in claim 14, wherein, The upper cover and the lower cover are made of transparent quartz.

16. The chemical vapor deposition apparatus as claimed in claim 13, wherein, The sidewall of the reaction chamber is provided with an air inlet and an air outlet for the input and output of process gases.

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