Wafer dry cleaning apparatus

Abstract

The present invention relates to a dry cleaning apparatus for a wafer, and more particularly, to a dry cleaning apparatus for a wafer which can effectively remove organic residues on a wafer surface using a laser. The present invention provides a dry cleaning apparatus for a wafer for dry cleaning organic residues on a wafer surface, wherein the dry cleaning apparatus for a wafer includes a laser light source which irradiates a laser light, a collimating optical system which makes the laser light irradiated from the laser light source travel in parallel, a uniformizing optical system which makes light passing through the collimating optical system uniform, and an imaging optical system for adjusting light passing through the uniformizing optical system to conform to the size of a wafer.

Description

Technical Field

[0001] This invention relates to a dry cleaning apparatus for wafers, and more specifically to a dry cleaning apparatus for wafers that can effectively remove organic residues from the surface of wafers using lasers. Background Technology

[0002] After semiconductor supercritical processes or wet cleaning processes, the surface of the dried wafer may contain various organic residues such as PR (photoresist) residue or IPT (isopropyl alcohol) residue. These residues on the wafer surface can affect the process input-output ratio, so they must be removed. However, when these residues are wet cleaned, problems such as leaching occur, making wet cleaning unsuitable. Therefore, dry cleaning is required.

[0003] As one type of dry cleaning method, devices are currently being developed or used that use light generators or heaters to heat the wafer to above the thermal reaction temperature of organic matter (600°C based on carbon) to clean residual organic matter. However, such devices suffer from long process times and low cleaning efficiency. Summary of the Invention

[0004] The present invention is proposed to solve the problems of the prior art. The problem to be solved by the present invention is to provide a wafer dry cleaning device that can complete the operation in a short time and has a high efficiency in removing organic residues on the wafer.

[0005] As a solution to the aforementioned problem, the present invention provides a dry cleaning apparatus for wafers, used for dry cleaning organic residues on the surface of wafers. The dry cleaning apparatus for wafers includes: a laser source for irradiating with laser light; a collimating optical system for causing the laser light irradiated from the laser source to travel in parallel; a uniform optical system for making the light passing through the collimating optical system uniform; and an imaging optical system for adjusting the light passing through the uniform optical system to conform to the dimensions of the wafer.

[0006] The uniform optical system may include a DOE (Diffractive Optical Element), or it may include a microlens array, or it may include a light tube, or it may be used in combination with at least one of a light tube, a DOE, and a microlens array.

[0007] Preferably, the dry cleaning apparatus for wafers further includes a refractive optical system for refracting the laser.

[0008] In addition, the present invention provides a dry cleaning apparatus for wafers, used for dry cleaning organic residues on the surface of wafers. The dry cleaning apparatus includes: a laser source for irradiating light; a first uniform optical system for making the light irradiated from the laser source uniform; a collimating optical system for making the laser light passing through the first uniform optical system travel parallel; a refractive optical system for refracting the light passing through the collimating optical system by 90 degrees; a second uniform optical system for making the light passing through the refractive optical system uniform; and an imaging optical system for adjusting the light passing through the second uniform optical system to conform to the dimensions of the wafer.

[0009] Furthermore, the present invention provides a dry cleaning apparatus for wafers, used for dry cleaning organic residues on the surface of wafers. The dry cleaning apparatus includes: a laser source for irradiating with laser light; a first uniform optical system for making the light irradiated from the laser source uniform; a collimating optical system for making the laser light passing through the first uniform optical system travel parallel; a refractive optical system for refracting the light passing through the collimating optical system by 90 degrees; a second uniform optical system for making the light passing through the refractive optical system uniform; an imaging optical system for adjusting the light passing through the second uniform optical system to conform to the dimensions of the wafer; a cooling unit for cooling the wafer heated by the laser irradiation; an air jet section disposed on one side of the wafer to spray inert gas onto the surface of the wafer; and an air suction section disposed on the opposite side of the air jet section to suction the inert gas sprayed by the air jet section and the organic residues on the surface of the wafer, having a width narrower than the air jet section.

[0010] According to the present invention, a wafer dry cleaning apparatus can be provided that completes the operation in a short time and has a high efficiency in removing organic matter from the wafer. Attached Figure Description

[0011] Figure 1 This is a diagram illustrating a dry cleaning apparatus for wafers according to a first embodiment of the present invention.

[0012] Figure 2 This is a diagram illustrating a dry cleaning apparatus for wafers according to a second embodiment of the present invention.

[0013] Figure 3 This is a diagram used to illustrate the particle removal unit.

[0014] Figures 4 to 6 This is a schematic diagram illustrating a dry cleaning apparatus for wafers according to a third embodiment of the present invention.

[0015] (Explanation of reference numerals in the attached diagram)

[0016] 10: Laser source; 20: Collimating optical system

[0017] 30: Uniform optical system; 40: Imaging optical system Detailed Implementation

[0018] The following describes preferred embodiments of the present invention to provide specific details for implementing the present invention.

[0019] First, a dry cleaning apparatus for wafers according to a first embodiment of the present invention will be described.

[0020] Figure 1 This is a diagram illustrating a dry cleaning apparatus for wafers according to a first embodiment of the present invention.

[0021] The wafer dry cleaning apparatus according to this embodiment is an apparatus for cleaning organic residues on the surface of wafers. As described in the background art, organic residues include PR residues, IPA residues, etc., and lasers are used to clean these organic residues. It is well known that laser cleaning cleans wafer surfaces using three mechanisms: photomechanical, photochemical, and photothermal. In this embodiment, the photothermal mechanism, which is most relevant to the removal of organic matter, is utilized. The mechanism is as follows: if organic particles adhering to the wafer surface are rapidly heated, they suddenly expand, and the expanded particles fall off the wafer surface and are removed.

[0022] like Figure 1 As shown, the wafer dry cleaning apparatus according to this embodiment is configured to include a laser light source 10, a collimation optical system 20, a uniform optical system 30, and an imaging optical system 40.

[0023] The laser light source 10 serves as the structure for irradiating the laser and can utilize fiber light sources, CO2 light sources, etc. In this embodiment, a fiber light source is used.

[0024] The collimating optical system 20 is a structure that enables the laser to travel parallel to each other. Collimated light is defined as light in which all rays within the speed of light are parallel to each other, and the collimating optical system 20 is a device for generating laser light that meets this definition.

[0025] The collimating optical system 20 can be like Figure 1 As shown in the summary, it consists of multiple lenses, including a collimating lens.

[0026] The uniform optical system 30 is a structure used to make the light passing through the collimating optical system 20 uniform.

[0027] The meaning of uniform light is that the light energy (energy) is uniform across all points within a specific area illuminated by light. Although it is impossible to make a laser 100% uniform, it can be made close to uniform by using various mechanisms, namely, by using a uniform optical system 30 that utilizes such mechanisms.

[0028] Because the uniform optical system 30 makes the laser irradiated on the surface of the wafer uniform, it can effectively remove organic residues present in all areas of the wafer surface.

[0029] The uniform optical system 30 may include a DOE (Diffractive Optical Element), which is an optical element that uses diffraction phenomena caused by periodic internal or surface structures to control the light path.

[0030] The uniform optical system 30 may include a microlens array. A microlens array refers to a plurality of lenses arranged in one or two dimensions in a medium, which can be used for purposes such as optical collimation or focusing; in this embodiment, it is used for optical collimation.

[0031] The uniform optical system 30 may also include a light pipe. A light pipe, as a structure that improves the uniformity of light emitted from a light source to make it direct light (light illuminating a specific area or object), can be used for optical collimation; in this embodiment, it is used for optical collimation.

[0032] On the other hand, the uniform optical system 30 may also include any one or a combination of a light pipe and a DOE and a microlens array. This means that it can be implemented in the form of a light pipe and a DOE, a light pipe and a microlens array, a light pipe, a DOE, and a microlens array, etc.

[0033] The imaging optical system 40, which adjusts the light passing through the uniform optical system 30 to conform to the dimensions of the wafer W, can be configured as a combination of multiple lenses, such as convex or concave lenses. Figure 1 As shown, if a diffused laser L is required, a concave lens is used.

[0034] The laser L emitted from the laser source 10 passes through the collimating optical system 20 and the homogenizing optical system 30 and passes through the imaging optical system 40 in a parallel and uniform state. The imaging optical system 40 adjusts (diffuses or shrinks) the laser to conform to the size of the wafer W and reaches the wafer W.

[0035] The laser L that reaches wafer W provides energy to the surface of wafer W and heats it, thereby separating and removing organic residues from the surface of wafer W.

[0036] Figure 1 The wafer dry cleaning apparatus shown is the closest to the prototype dry cleaning apparatus used to illustrate the structure of the laser source 10, collimating optical system 20, uniform optical system 30, imaging optical system 40, etc.

[0037] Hereinafter, a second embodiment of the present invention will be described with reference to the accompanying drawings. The dry cleaning apparatus according to this embodiment is a device with several additional structures added to the dry cleaning apparatus according to the previously described embodiment. The description will focus on the additional structures added to the previously described dry cleaning apparatus, while the structures included in the previous embodiments will be briefly described.

[0038] Figure 2 This is a diagram illustrating a dry cleaning apparatus for wafers according to a second embodiment of the present invention. Figure 3 This is a diagram used to illustrate the particle removal unit.

[0039] The wafer dry cleaning apparatus according to this embodiment is configured to include a refractive optical system, a particle removal unit, and a cooling unit compared to the wafer dry cleaning apparatus of the previous embodiment. The laser L irradiated from the laser source 110 passes through the first uniform optical system 120, the collimating optical system 130, the refractive optical system 140, the second uniform optical system 150, and the imaging optical system 160 to irradiate the wafer W.

[0040] The first uniform optical system 120 and the second uniform optical system 150 are substantially the same as the uniform optical system of the first embodiment described above. The collimating optical system 130 or the imaging optical system 160 are also substantially the same as the corresponding structures in the first embodiment, so additional descriptions are omitted.

[0041] The refractive optical system 140, as a structure that can change the direction of laser L through refraction, can use a mirror.

[0042] The refractive optical system 140 is used in this embodiment because when the laser source 110 is a fiber optic source, it may be difficult to control if the fiber optic source is set vertically. Therefore, the fiber-type laser source 110 is set horizontally and used by refraction in the vertical direction through the refractive optical system 140.

[0043] The particle removal unit is a structure for effectively removing organic particles if the laser L irradiates the wafer W and rapidly heats the organic particles attached to the wafer surface, causing the organic particles to expand and separate from the wafer W. It includes an air jet section 210, an air suction section 220, and a flow path 230.

[0044] The air jet section 210 is as follows: Figure 3 The structure shown sprays inert gas onto the surface of wafer W. The air suction unit 220 is located on the opposite side of the air jet unit 210 and is connected to a vacuum pump to suction the inert gas sprayed by the air jet unit 210 and organic residues on the wafer surface.

[0045] On the other hand, the air suction section 220 is narrower than the air injection section 210. With this structure, the flow velocity of the inert gas increases towards the air suction section 220. When the flow rate is constant, if the flow cross-sectional area decreases, the fluid velocity increases. The narrow width of the air suction section 220 means that the flow cross-sectional area on the air suction section 220 side is smaller, thus the fluid movement speed increases.

[0046] If the velocity of the inert gas is increased, it can be expected to effectively remove particles (organic residues) from the wafer surface.

[0047] The flow path 230 serves as a space between the air injection section 210 and the air suction section 220, allowing inert gas to flow, and a wafer W is disposed in the flow path 230.

[0048] The cooling unit 300 is a structure disposed below the wafer W for cooling the wafer W heated by the laser L. According to the research of Li Minghua et al. (Surface cleaning of wafers using laser cleaning technology; published in the Korean Journal of Liquid Particulate Chemistry, Vol. 12, No. 4), if the wafer is cooled, the efficiency of organic matter removal may decrease due to the photothermal mechanism. Therefore, it is preferable to activate the cooling unit 300 after irradiating the wafer W with the laser L and removing particles by the particle removal unit 200.

[0049] Figures 4 to 6 The wafer dry cleaning apparatus shown according to a third embodiment of the present invention is an embodiment using multiple refractive optical systems. In this embodiment, when there is a limitation on height in the arrangement of the wafer dry cleaning apparatus, it is configured to have a horizontally oriented laser L path, rather than as... Figure 1 or Figure 2 The embodiment shown is configured to have a laser path that is long in the vertical direction.

[0050] The laser L emitted from the laser source 1 is refracted three times in the first refractive optical system 2, the second refractive optical system 4, and the third refractive optical system 7, and then shines downward through the through-hole 8 to reach the wafer.

[0051] Reference numerals 3, 5, and 6 in the attached figures indicate optical systems. Uniform optical systems, collimating optical systems, and imaging optical systems can be used. Only three optical systems are briefly shown in the figures, but their number and types are not limited.

[0052] On the other hand, Figures 1 to 6 In the attached diagram, reference numeral C indicates a housing that internally accommodates various optical systems.

Claims

1. A dry cleaning apparatus for wafers, used for dry cleaning organic residues on the surface of wafers, wherein, The dry cleaning apparatus for wafers includes: Laser source, irradiating with laser light; A collimating optical system that allows the laser light emitted from the laser source to travel in parallel; A uniform optical system, which makes the light passing through the collimating optical system uniform; An imaging optical system for adjusting light passing through the uniform optical system to conform to the dimensions of the wafer; and The particle removal unit provides an airflow for removing organic residues that have been removed from the wafer by light irradiating the wafer. The particle removal unit includes: An air jetting section is disposed on one side of the wafer and jets gas onto the surface of the wafer; and An air suction unit, located on the opposite side of the air jet unit, suctions the gas ejected by the air jet unit and organic residues separated from the wafer surface by the laser. The width of the air jet section is wider than the width of the air suction section.

2. The dry cleaning apparatus for wafers according to claim 1, wherein, The uniform optical system includes diffractive optical elements.

3. The dry cleaning apparatus for wafers according to claim 1, wherein, The uniform optical system includes a microlens array.

4. The dry cleaning apparatus for wafers according to claim 1, wherein, The uniform optical system includes a light tube.

5. The dry cleaning apparatus for wafers according to claim 1, wherein, The uniform optical system is used in combination with at least one of a light tube, a diffractive optical element, and a microlens array.

6. The dry cleaning apparatus for wafers according to any one of claims 1 to 5, wherein, The dry cleaning apparatus for wafers also includes a refractive optical system for refracting the laser.

7. The dry cleaning apparatus for wafers according to claim 6, wherein, The dry cleaning apparatus for wafers uses multiple refractive optical systems.

8. A dry cleaning apparatus for wafers, used for dry cleaning organic residues on the surface of wafers, wherein, The dry cleaning apparatus for wafers includes: Laser source, irradiating with laser light; A first uniform optical system makes the light irradiated from the laser source uniform; A collimating optical system that allows the laser light passing through the first uniform optical system to travel in parallel; A refractive optical system for refracting light passing through the collimating optical system by 90 degrees; The second uniform optical system makes the light passing through the refractive optical system uniform; An imaging optical system for adjusting light passing through the second uniform optical system to conform to the dimensions of the wafer; and The particle removal unit provides an airflow for removing organic residues that have been removed from the wafer by light irradiating the wafer. The particle removal unit includes: An air jetting section is disposed on one side of the wafer and jets gas onto the surface of the wafer; and An air suction unit, located on the opposite side of the air jet unit, suctions the gas ejected by the air jet unit and organic residues separated from the wafer surface by the laser. The width of the air jet section is wider than the width of the air suction section.

9. The dry cleaning apparatus for wafers according to claim 8, wherein, The first uniform optical system or the second uniform optical system includes diffractive optical elements.

10. The dry cleaning apparatus for wafers according to claim 8, wherein, The first uniform optical system or the second uniform optical system includes a microlens array.

11. The dry cleaning apparatus for wafers according to claim 8, wherein, The first uniform optical system or the second uniform optical system includes a light tube.

12. The dry cleaning apparatus for wafers according to claim 8, wherein, The first uniform optical system or the second uniform optical system is used in combination with at least one of a light tube and a diffractive optical element and a microlens array.

13. The dry cleaning apparatus for wafers according to any one of claims 8 to 12, wherein, The dry cleaning apparatus for wafers also includes a refractive optical system for refracting the laser.

14. The dry cleaning apparatus for wafers according to claim 1 or 8, wherein, The dry cleaning apparatus for wafers also includes a cooling unit disposed below the wafer for cooling the wafer.

15. The dry cleaning apparatus for wafers according to claim 1 or 8, wherein, The gas ejected from the air jet is an inert gas.

16. The dry cleaning apparatus for wafers according to claim 13, wherein, The dry cleaning apparatus for wafers uses multiple refractive optical systems.

17. A dry cleaning apparatus for wafers, used for dry cleaning organic residues on the surface of wafers, wherein, The dry cleaning apparatus for wafers includes: Laser source, irradiating with laser light; A first uniform optical system makes the light irradiated from the laser source uniform; A collimating optical system that allows the laser light passing through the first uniform optical system to travel in parallel; A refractive optical system for refracting light passing through the collimating optical system by 90 degrees; The second uniform optical system makes the light passing through the refractive optical system uniform; An imaging optical system for adjusting light passing through the second uniform optical system to conform to the dimensions of the wafer; A cooling unit for cooling the wafer heated by the laser irradiation; An air jetting section is disposed on one side of the wafer and jets inert gas onto the surface of the wafer; and An air suction section is provided on the side opposite to the air jet section to suction inert gas and organic residues on the surface of the wafer that are ejected by the air jet section, and has a narrower width than the air jet section.

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