Automatic laser drying device for semiconductor wafer

Abstract

The disclosed automatic laser drying device for a semiconductor wafer comprises: a laser beam irradiation unit including a laser beam generator, which uses a continuous-wave infrared-wavelength laser and generates a laser beam in order to irradiate the laser beam toward a semiconductor wafer, a laser beam transmitter for transmitting the laser beam generated by the laser beam generator, and a laser beam irradiator for irradiating the surface of the semiconductor wafer with the laser beam; a wafer rotating unit for rotating the semiconductor wafer; an arm, spaced apart from the semiconductor wafer, that swings or moves linearly around a rotation axis positioned in the outer area of the semiconductor wafer; a head assembly including the laser beam irradiator, an IPA nozzle for spraying isopropyl alcohol, and an N2 nozzle for spraying nitrogen; a vision camera for sensing, in real time, during a drying process, a drying boundary line positioned in an area irradiated with a laser beam; and a controller for controlling the arm such that the drying boundary line is positioned in the area irradiated with the laser beam.

Description

Automatic laser drying device for semiconductor wafers

[0001] The present invention relates to an apparatus for drying the surface of a semiconductor wafer using a laser, and specifically, to an automatic laser drying apparatus for a semiconductor wafer that uses a laser to dry ultrapure water and isopropyl alcohol (IPA) present on the semiconductor wafer after a cleaning process of the semiconductor wafer.

[0002] As high integration through semiconductor pattern miniaturization becomes more advanced, recent advanced semiconductors include ultra-fine structures with pattern sizes of 20 nm or less, and the aspect ratio of patterns in critical processes such as Shallow Trench Isolation (STI) patterns, Gate patterns, and Capacitor pattern formation processes is reaching 30 or higher. To form patterns with such high aspect ratios on a semiconductor wafer, advanced technological development is required not only in the photolithography and dry etching processes but also in the wet cleaning process to remove contaminants remaining after the dry etching process.

[0003] In the wet cleaning process, the semiconductor wafer is generally rotated at high speed, a cleaning solution is dispensed, and the wafer undergoes steps of ultrapure water rinsing and drying. During these steps, as the width of fine patterns decreases and the aspect ratio increases, the volume of ultrapure water inside the patterns decreases during the drying process. Consequently, capillary forces pull adjacent patterns together, causing them to stick to one another. This phenomenon is referred to as pattern leaning, and the importance of drying technology is becoming increasingly prominent in relation to the pattern leaning issue.

[0004] Figure 1 is a schematic diagram of the principle of pattern damage occurring during the semiconductor wafer drying process. Referring to Figure 1, the capillary force (σ) acting between patterns (P) is proportional to the surface tension (γ) (see the formula in Figure 1 (a)). Therefore, in semiconductor wafer drying technology, techniques have been developed to lower the surface tension of the liquid on the wafer at the moment of drying in order to avoid such pattern lining. When the surface tension is high, if the volume within the fine pattern decreases, pattern lining occurs during the drying process due to the high capillary force (see Figures 1 (b) and (c)). Therefore, to lower the capillary force, pattern lining during the drying process could be reduced by using IPA (Isopropyl alcohol), which has low surface tension, instead of ultrapure water, which has high surface tension (see Figure 1 (d)), and the surface tension could be further lowered by using high-temperature IPA in the next step.

[0005] Recently, as pattern sizes have become smaller and aspect ratios have increased, supercritical carbon dioxide (CO2) fluid has been applied to the drying process in some advanced processes. Since the surface tension of supercritical carbon dioxide fluid is zero, it does not generate capillary forces even if the volume of the fluid inside the pattern decreases during the drying process, thereby enabling drying without pattern lining. However, the supercritical carbon dioxide process is carried out under supercritical point conditions, namely a temperature of 31.1°C and a pressure of 73.8 Bar or higher (typically around 100 Bar), which requires an expensive ultra-high pressure chamber and an ultra-high pressure carbon dioxide supply system. Furthermore, the process is very complex because ultrapure water must be replaced with IPA first, and the wafer must be transferred from a wet cleaning chamber to an ultra-high pressure drying chamber in a wet state. In addition, this leads to an increase in the manufacturing cost of supercritical carbon dioxide process equipment and a decrease in the number of wafers that can be processed per hour, resulting in a decrease in productivity to less than one-fifth of that of the conventional process and, consequently, a problem in which the cost of the cleaning process increases by more than five times. Therefore, due to these various problems, the supercritical carbon dioxide process is difficult to apply universally in the drying process.

[0006] The present invention was devised to solve the aforementioned problems.

[0007] The problem that the present invention aims to solve is to provide an automatic laser drying device for semiconductor wafers that reduces the capillary force causing pattern lining in fine patterns by maximizing the temperature of the liquid IPA and minimizing the surface tension of the liquid IPA during the drying process after wet cleaning of a semiconductor wafer, by replacing ultrapure water with IPA to remove IPA on the wafer and irradiating an infrared laser of a wavelength that is well absorbed at the drying point (drying boundary line).

[0008] Another problem that the present invention aims to solve is to provide an automatic laser drying device for semiconductor wafers that can solve the problem of reduced efficiency in the drying process of a semiconductor wafer using a laser, which occurs when an infrared laser is irradiated from the irradiation unit to the drying boundary line on the wafer, and the infrared laser is not positioned correctly on the drying boundary line.

[0009] An automatic laser drying device for a semiconductor wafer according to one aspect of the present invention for solving the above problem comprises: a laser beam generating unit for generating a laser beam to use a laser of a continuous wave infrared wavelength and to irradiate a laser beam toward a semiconductor wafer, a laser beam transmitting unit for transmitting a laser beam generated by the laser beam generating unit, and a laser beam irradiating unit for irradiating a laser beam transmitted through the laser beam transmitting unit onto the surface of the semiconductor wafer; a wafer rotation unit for rotating the semiconductor wafer; an arm that swings or moves in a straight line while spaced apart from the semiconductor wafer around a rotation axis located in an outer region of the semiconductor wafer; a head assembly comprising the laser beam irradiating unit, an IPA nozzle for spraying isopropyl alcohol (IPA), and an N2 nozzle for spraying nitrogen gas (N2); a vision camera for sensing a drying boundary line located within an area receiving the laser beam on the surface of the semiconductor wafer in real time during the drying process; and, according to the sensing result of the vision camera, when the drying boundary line moves out of the area receiving the laser beam, the drying boundary line It is characterized by including a control unit for controlling the arm to be positioned within an area receiving a laser beam.

[0010] According to one embodiment, the laser beam irradiation unit includes a selective wavelength reflection mirror that reflects only the laser beam in the infrared wavelength band from the laser beam transmitted through the laser beam transmission unit and transmits other wavelength bands including visible light.

[0011] According to one embodiment, the vision camera is positioned on the upper part of the head assembly and receives visible light passing through the selected wavelength reflecting mirror to sense the drying boundary line.

[0012] According to one embodiment, the semiconductor wafer automatic laser drying device further includes a lighting unit that provides illumination toward the semiconductor wafer side for real-time sensing of the drying boundary line by the vision camera.

[0013] According to one embodiment, the laser beam irradiation unit uses a continuous wave infrared laser beam in the range of 2,000 to 4,000 nm or 6,500 nm to 12,500 nm.

[0014] According to one embodiment, the semiconductor wafer automatic laser drying device may further include an infrared camera installed on the upper part of the semiconductor wafer to monitor all processes in which the wafer drying process is carried out by the laser beam irradiation unit.

[0015] The present invention provides an automatic laser drying device for semiconductor wafers, and in the process of proceeding with a drying process after wet cleaning of a semiconductor wafer, by replacing ultrapure water with IPA to remove IPA on the wafer, an infrared laser of a wavelength that is well absorbed is irradiated at the drying point (drying boundary line), thereby maximally increasing the temperature of the IPA liquid and maximally lowering the surface tension of the IPA, thereby having the effect of lowering the capillary force that causes pattern lining in fine patterns.

[0016] In addition, the present invention provides an automatic laser drying device for a semiconductor wafer comprising a vision camera, a lighting unit, and a control unit, which are components for positioning the infrared laser irradiation unit at the drying boundary line of the semiconductor wafer, thereby ensuring that the infrared laser irradiated by the infrared laser irradiation unit is always positioned at the drying boundary line during the drying process, thus having the effect of increasing the efficiency of the drying process of the semiconductor wafer using a laser.

[0017] It should be noted that the effects of the present invention are further mentioned in the following 'Specific details for implementing the invention' section, in addition to the effects listed above.

[0018] FIG. 1 is a schematic diagram of the principle of pattern damage occurring during the semiconductor wafer drying process, and

[0019] FIG. 2 is a schematic diagram briefly illustrating the features of a semiconductor wafer drying device not equipped with a vision camera and a control unit, and

[0020] FIG. 3 is a drawing for explaining a semiconductor wafer drying process using the semiconductor wafer drying apparatus of FIG. 2, and

[0021] FIG. 4 is a drawing for explaining the features of an automatic laser drying device for semiconductor wafers according to one embodiment of the present invention.

[0022] The present invention is basically a device for drying ultrapure water and IPA present after a semiconductor wafer cleaning process, comprising a continuous wave laser generator having an infrared wavelength, a laser transmission device composed of a reflective mirror and a barrel, a laser optical device composed of a lens, and a drying arm device equipped with a laser device and IPA and N2 nozzles to scan the front surface of the wafer to be dried, and thereby effectively removing liquids such as ultrapure water and IPA present inside the fine pattern on the wafer surface without damaging the fine pattern on the wafer surface. Furthermore, in order to compensate for the disadvantage of reduced process efficiency caused by the laser beam not being accurately irradiated to the drying point during the process of drying a semiconductor wafer using such a drying device, the invention relates to an automatic laser drying device for semiconductor wafers that senses in real time the drying point—that is, the boundary between the part where the drying process has been performed and the part where it has not yet been performed (hereinafter referred to as the 'drying boundary line (DBL)' for convenience) during the process of gradually proceeding drying from the center of the semiconductor wafer toward the edge—and controls the arm to adjust the position of the head assembly so that the laser beam is accurately irradiated to the drying point during the process.

[0023] Hereinafter, an automatic laser drying apparatus for semiconductor wafers according to a preferred embodiment of the present invention will be described with reference to the attached drawings. It should be noted that the attached drawings and the embodiments described with reference thereto are simplified and illustrative for the purpose of assisting those skilled in the art in understanding the present invention. Furthermore, it should be noted that the shapes of the components or their positional relationships in the attached drawings are simplified for the purpose of explaining the features of the present invention. Additionally, within this specification, IPA is used as a term referring to isopropyl alcohol, and N2 is used as a term meaning nitrogen gas.

[0024] FIG. 2 is a schematic diagram briefly illustrating the features of a semiconductor wafer drying device (100) not equipped with a vision camera and a control unit, FIG. 3 is a diagram for explaining the semiconductor wafer drying process and drying boundary line (DBL) using the semiconductor wafer drying device (100) of FIG. 2, and FIG. 4 is a diagram for explaining the features of an automatic laser drying device (100') for semiconductor wafers according to an embodiment of the present invention. In FIG. 4, for convenience, only the configuration of a laser beam irradiation unit (111, 112, 113; 110), a vision camera (170), a control unit (180), and an illumination unit (190) is shown, but it should be noted that the basic configuration of the head assembly (HA) shown in FIG. 2 remains the same. That is, the semiconductor wafer automatic laser drying device (100') shown in FIG. 4 should be understood as having all the features of the semiconductor wafer drying device (100) shown in FIG. 2, while additionally including the components of a vision camera (170), a control unit (180), and a lighting unit (190).

[0025] Accordingly, referring to FIGS. 2 to 4 together, a semiconductor wafer automatic laser drying device (100') according to one embodiment of the present invention includes a laser beam irradiation unit (110), a wafer rotation unit (150), an arm (120), a head assembly (HA), a vision camera (170), and a control unit (180). In addition, the semiconductor wafer automatic laser drying device (100') according to one embodiment of the present invention may further include an illumination unit (190). In addition, it may further include an infrared camera (200) located above the semiconductor wafer (W). Reference numeral 160 is a wafer fixing unit.

[0026] First, regarding the wafer rotation unit (150) and the wafer fixing unit (160), the wafer fixing unit (150) fixes the semiconductor wafer (W) with the upper surface of the semiconductor wafer (W) exposed, and the wafer rotation unit (150) rotates the semiconductor wafer (W) by driving the wafer fixing unit (160) to rotate, and is positioned on the upper part of the wafer fixing unit (160).

[0027] Although not shown in FIGS. 2 and 4, an ultrapure water spray nozzle may also be provided to spray ultrapure water onto the upper surface of the semiconductor wafer (W) for rinsing the upper surface of the semiconductor wafer (W) after wet cleaning. Prior to drying the wafer (W) using IPA, a laser beam, and N2, an appropriate cleaning solution is sprayed onto the upper surface of the semiconductor wafer (W) while the semiconductor wafer (W) is rotating in order to remove impurities present on the surface of the semiconductor wafer (W), and ultrapure water is sprayed to replace the cleaning solution with ultrapure water. The semiconductor wafer automatic laser drying device (100') of the present invention is configured to rotate the semiconductor wafer (W) at high speed using a wafer rotation unit (150), replace the ultrapure water filled between the fine patterns formed on the surface of the semiconductor wafer with IPA, and then dry the replaced IPA using a laser beam and N2.

[0028] To this end, the semiconductor wafer automatic laser drying device (100') of the present invention includes a head assembly (HA) for proceeding with the drying process of a semiconductor wafer (W). The head assembly (HA) includes an IPA nozzle (140) for spraying IPA onto the upper surface of a semiconductor wafer (W) that is rotating, an N2 nozzle (130) for spraying nitrogen gas (N2) onto the upper surface of a semiconductor wafer (W) that is rotating, and a laser beam irradiation unit (113) for irradiating a laser beam generated using a laser of a continuous wave infrared wavelength toward the semiconductor wafer (W) that is rotating. The head assembly (HA) is located at one end of an arm (120).

[0029] The arm (120) participates in the drying process of the semiconductor wafer (W) by swinging or moving in a straight line while spaced apart from the semiconductor wafer (W) at the top of the semiconductor wafer (W), centered on a rotation axis located in the outer region of the semiconductor wafer (W). Here, the outer region of the semiconductor wafer (W) refers to any region other than the upper region of the semiconductor wafer (W) (e.g., any region in the right direction of the arrow indicated by the scan in FIG. 2 or in the left direction of the arm (120) in FIG. 4). By swinging or moving in a straight line, the head assembly (HA) is able to scan the entire region of the semiconductor wafer (W).

[0030] In the semiconductor wafer automatic laser drying device (100') of the present invention, the IPA nozzle (140) and the N2 nozzle (130) are arranged so that the IPA sprayed onto the semiconductor wafer (W) through the IPA nozzle (140) (specifically through the nozzle of the IPA nozzle) and the N2 sprayed onto the semiconductor wafer (W) through the N2 nozzle (specifically through the nozzle of the N2 nozzle) are sprayed in directions that intersect each other. Meanwhile, the laser beam irradiation unit (113) is arranged so that a laser beam can be irradiated perpendicular to the semiconductor wafer (W) in order to heat the IPA sprayed onto the semiconductor wafer (W) so as to raise its temperature.

[0031] The laser beam irradiation unit (110) includes a laser beam generating unit (111) that generates a laser beam, a laser beam transmitting unit (112) that transmits the laser beam generated from the laser beam generating unit (111), and a laser beam irradiation unit (113) that irradiates the laser beam transmitted through the laser beam transmitting unit (112) onto the surface of a semiconductor wafer (W). The laser beam irradiation unit (113) uses a continuous wave infrared laser beam within the range of 2,000 to 4,000 nm or 6,500 nm to 12,500 nm.

[0032] In the laser beam irradiation unit (110), the laser beam irradiation section (113) includes a selective wavelength reflecting mirror (1131) and a focusing lens (1132). The selective wavelength reflecting mirror (1131) reflects only the laser beam in the infrared wavelength band from the laser beam transmitted through the laser beam transmission section (112) and transmits the laser beam in other wavelength bands, including visible light. In FIG. 4, for better understanding, the laser beam in the infrared wavelength band is represented by a solid line, and the visible light is represented by a dotted line.

[0033] FIGS. 2 and FIGS. 4 described herein are drawings that simply illustrate the characteristic configuration of an automatic laser drying device for semiconductor wafers according to one embodiment of the present invention, and such simplified configuration should not be interpreted as limiting the scope of the present invention.

[0034] A vision camera (170) is a component for sensing a drying boundary line (DBL) located within an area receiving a laser beam (a laser beam with a width of d1 in FIG. 3) on the surface of a semiconductor wafer (W) in real time during the drying process. The vision camera (170) is a component located on the upper part of a head assembly (HA) and receiving visible light that has passed through a selective reflection wavelength mirror (1131) to sense the drying boundary line (DBL). The vision camera (170) may be configured to be included inside the head assembly (HA) or configured to be connected to the outside of the head assembly (HA).

[0035] The control unit (180) is a component for sensing, based on the sensing result of the vision camera (170), when the drying boundary line (DBL) moves out of the area receiving the laser beam and the drying boundary line (DBL) is not receiving the laser beam, and controlling the arm (120) to move the head assembly (HA) so that the drying boundary line (DBL) is positioned within the area receiving the laser beam.

[0036] The lighting unit (190) is a component for providing illumination toward the semiconductor wafer (W) so that real-time sensing of the drying boundary line (DBL) by the vision camera (170) can be performed more smoothly. As shown in FIG. 4, the lighting unit (190) is added to the lower outer side of the head assembly and illuminates toward the semiconductor wafer (W), thereby preventing real-time sensing failures in the vision camera (170) caused by a lack of visible light reflected through the semiconductor wafer (W).

[0037] The infrared camera (200) is a component for visually monitoring whether the entire drying process is being properly performed through laser beam irradiation on the surface of the semiconductor wafer (W). Since the infrared camera (200) is intended to monitor the entire wafer where the drying process is taking place, it is configured to be separated from the head assembly (HA) and located in an independent location on the upper part of the wafer. It is also possible to determine whether the drying process is being properly performed by software by analyzing the infrared images acquired from the infrared camera (200) in real time.

[0038] Referring to FIGS. 2 to 4, the sequence of the semiconductor wafer drying process according to the present invention is described as follows: First, a semiconductor wafer (W) is rotated using a wafer rotation unit (150), and a suitable cleaning solution is sprayed onto the rotating semiconductor wafer (W) to remove impurities from the surface. Then, ultrapure water is sprayed to replace the cleaning solution. Next, an arm (120) equipped with a head assembly (HA) having an IPA nozzle is positioned at the center of the semiconductor wafer (W), and IPA is sprayed to replace the ultrapure water on the semiconductor wafer (W) with IPA. At this time, the rotation speed of the semiconductor wafer (W) is set to a range of 500 rpm to 1,200 rpm. Additionally, after spraying IPA, it is maintained for a sufficient amount of time so that the inside of the fine pattern is completely replaced with IPA. Subsequently, the rotation speed (rpm) of the semiconductor wafer (W) is increased to thin the thickness of the IPA liquid layer on the surface of the semiconductor wafer so that it can be dried more easily. In this case, the surface of the semiconductor wafer (W) must not be exposed anywhere on the wafer, that is, the entire surface of the semiconductor wafer (W) must be covered with the IPA liquid layer (liquid film). If the surface of the semiconductor wafer (W) is exposed, a drying defect may occur in that area. In a conventional semiconductor wafer drying method using IPA (a conventional semiconductor wafer drying method different from the method of the present invention, which locally heats the semiconductor wafer by spraying IPA using a laser beam), the process is carried out by spraying IPA that has been heated to approximately 60 to 70°C to cover the upper surface of the semiconductor wafer (W) with IPA at a relatively high temperature. However, when the drying process is carried out by spraying IPA heated to such a high temperature as is, rapid cooling occurs due to heat loss caused by evaporative heat compared to using low-temperature IPA (as explained in more detail below), and especially when the rotation speed of the semiconductor wafer (W) is increased, cooling is further accelerated, resulting in drying defects.Accordingly, the semiconductor wafer automatic laser drying device of the present invention utilizes a method in which IPA at room temperature (generally around 15°C to 25°C) is sprayed toward the semiconductor through an IPA nozzle, and selectively and locally heated only at the drying point using a laser beam. In other words, the semiconductor wafer automatic laser drying device of the present invention utilizes the IPA sprayed by the IPA nozzle in its room temperature state without any heating or temperature control, and uses a method in which the IPA is heated only at the drying point using a laser beam during the drying process. In this process, if the drying process proceeds without the laser beam being irradiated toward the drying point (i.e., the drying boundary line), the purpose of heating only at the drying point using a laser beam becomes meaningless, and more drying defects may occur. Therefore, as mentioned above, the drying boundary line is sensed in real time through a vision camera (170) during the drying process, and if the head assembly (HA) is not positioned so that the laser beam is irradiated toward the drying boundary line, the arm is controlled through the control unit (180).

[0039] Next, when the surface of the semiconductor wafer (W) is sufficiently covered with IPA, the arm (120) is set so that the head assembly (HA) is positioned at the center of the semiconductor wafer (W), and N2 is sprayed toward the center of the semiconductor wafer (W) through the N2 nozzle (130) installed near the IPA nozzle (140) in the head assembly (HA). As the IPA liquid film opens due to the N2 spraying from the N2 nozzle (130), drying occurs as the IPA liquid film on the surface, that is, the central part of the semiconductor wafer (W), is removed. Caution is required because if this process is carried out abruptly, a degree defect may occur due to incomplete drying. In this state, if the arm (120) is moved at a constant speed so that the head assembly moves outward (edge ​​direction) of the semiconductor wafer (W) around the axis of rotation, the circular drying area on the semiconductor wafer (W) expands with an increased radius by the distance the arm moves, and the semiconductor wafer drying process is completed when it reaches the edge of the wafer. As the drying area per unit time increases as it moves outward from the semiconductor wafer, the movement speed of the arm (120), the rotation speed (rpm) of the semiconductor wafer, the injection flow rate of N2, and the injection flow rate of IPA must be optimally adjusted according to the position of the arm (120) (e.g., can be distinguished by the radius of a virtual concentric circle (VC) in the part where the head assembly (HA) is located) in order to prevent defects caused by incomplete drying.

[0040] In the conventional semiconductor wafer drying method using IPA, as mentioned earlier, the intention was to reduce pattern lining by using high-temperature IPA to raise the temperature of the IPA at the drying point and thereby lowering the surface tension of the IPA. However, during the process of rotating the semiconductor wafer at high speed, the thickness of the IPA liquid film at the drying point becomes thin, being less than a few micrometers. Typically, a large volume of air is blown over the wafer to maintain downflow in the cleaning chamber, and at the same time, N2 is blown at the drying point. As this cools the wafer surface and causes heat loss due to the evaporative heat of the IPA, the thin IPA liquid film at the drying point cools rapidly. Consequently, the drying proceeds with the temperature of the IPA at the drying point lowered by up to 20°C to 30°C compared to the high temperature at the time of spraying (generally in the range of 60°C to 70°C). Therefore, the effect of reducing surface tension expected by raising the intended IPA temperature is limited, and the improvement effect on pattern lining through this is inevitably diminished. In other words, in the conventional high-temperature IPA drying process, the high temperature of the IPA is maintained outside the drying zone, but a much lower temperature is processed at the actual drying point, thereby reducing the effect of raising the temperature.

[0041] Therefore, to prevent this, the semiconductor automatic laser wafer drying device of the present invention sprays IPA at room temperature (generally around 15°C to 25°C) instead of high-temperature IPA and irradiates a laser beam at the drying point to heat the IPA to its boiling point (generally 82.6°C). This allows the surface tension of the IPA to be lowered to its minimum value at the moment of drying, thereby reducing the magnitude of the capillary force and expanding the process window without pattern leaning. The laser used at this time is at the peak position of the absorption spectrum of IPA, which is 2,000 to 4,000 nm or 6,500 to 12,500 nm. By using a range of wavelengths to maximize the absorption of IPA, it is possible to effectively raise the temperature.

[0042] When using the semiconductor wafer automatic laser drying device of the present invention described above, first, by expanding the process window without pattern leaning in the IPA drying process, it can be applied to the semiconductor wafer drying process with a relatively low aspect ratio among processes applying supercritical CO2 drying, and additionally, the existing semiconductor wafer drying process using IPA substitution can be improved into a more uniform and stable process without using high-temperature IPA. Furthermore, drying defects can be minimized by sensing the drying boundary line in real time through a vision camera during the drying process and controlling the arm through the control unit (180) so that the laser beam can be irradiated to the drying boundary line.

[0043] The above description merely illustrates preferred embodiments of the present invention, and those skilled in the art should be aware that modifications and changes can be made to the present invention without altering the gist of the invention, and should be noted that the scope of the present invention is defined by the following claims.

[0044] <Explanation of Symbols>

[0045] 100' : Automatic laser drying device for semiconductor wafers of the present invention

[0046] 110 : Laser beam irradiation unit

[0047] 120 : Aam

[0048] 130 : N2 nozzle

[0049] 140 : IPA (Isopropyl Alcohol) Nozzle

[0050] 170 : Vision Camera

[0051] 180 : Control unit

[0052] 190 : Lighting section

[0053] 200: Infrared camera

Claims

1. As an automatic laser drying device for semiconductor wafers, A laser beam irradiation unit comprising a laser beam generating unit for generating a laser beam to use a continuous wave infrared wavelength laser and irradiate a laser beam toward a semiconductor wafer, a laser beam transmitting unit for transmitting the laser beam generated by the laser beam generating unit, and a laser beam irradiation unit for irradiating the surface of the semiconductor wafer with the laser beam transmitted through the laser beam transmitting unit; A wafer rotation unit for rotating the above semiconductor wafer; An arm that swings or moves in a straight line while spaced apart from the semiconductor wafer, centered on a rotation axis located in the outer region of the semiconductor wafer; A head assembly comprising the above-mentioned laser beam irradiation unit, an IPA nozzle for spraying isopropyl alcohol (IPA), and an N2 nozzle for spraying nitrogen gas (N2); A vision camera for sensing a drying boundary line located within an area receiving the laser beam on the surface of the semiconductor wafer in real time during the drying process; and A semiconductor wafer automatic laser drying device characterized by including a control unit for controlling the arm such that, depending on the sensing result of the vision camera, when the drying boundary line moves out of the area receiving the laser beam, the drying boundary line is positioned within the area receiving the laser beam.

2. In Claim 1, A semiconductor wafer automatic laser drying device, characterized in that the laser beam irradiation unit includes a selective wavelength reflection mirror that reflects only the laser beam in the infrared wavelength band from the laser beam transmitted through the laser beam transmission unit and transmits other wavelength bands including visible light.

3. In Claim 2, A semiconductor wafer automatic laser drying device characterized in that the vision camera is located on the upper part of the head assembly and receives visible light passing through the selected wavelength reflection mirror to sense the drying boundary line.

4. In claim 3, the semiconductor wafer automatic laser drying device is, A semiconductor wafer automatic laser drying device characterized by further including a lighting unit that provides illumination toward the semiconductor wafer side for real-time sensing of the drying boundary line by the vision camera.

5. An automatic laser drying apparatus for semiconductor wafers according to claim 1, wherein the laser beam irradiation unit uses a continuous wave infrared laser beam within the range of 2,000 to 4,000 nm or 6,500 nm to 12,500 nm.

6. In claim 1, the semiconductor wafer automatic laser drying device is, A semiconductor wafer automatic laser drying device characterized by further including an infrared camera installed on the upper surface of the semiconductor wafer to monitor all processes in which the wafer drying process is carried out by the laser beam irradiation unit.

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