TWI489100B - Method and apparatus for examining contamination of substrate with optical recognition system - Google Patents

Description

Device for inspecting substrate contamination by optical identification system and method thereof

The present invention relates to an apparatus for inspecting substrate contamination and a method thereof, and more particularly to an apparatus and method for inspecting substrate contamination using an optical identification system.

In recent years, electronic products have flourished, and semiconductor devices have been widely used in many electronic products because of their high degree of integration, lightness, and shortness, such as processors, memory, and others. Integrated circuit (IC), light-emitting diode (LED), charge coupled device (CCD), complementary metal oxide semiconductor (CMOS), etc. In terms of image display, an LCD panel, or a LED panel, and an OLED panel are widely used due to an increase in demand for a flat display. Furthermore, package substrates and printed circuit boards (PCBs) are indispensable components in integrated circuit components and many electronic devices.

Most of these products or semi-finished products are manufactured on a substrate. For example, semiconductor devices are mostly fabricated on a semiconductor substrate such as a germanium substrate, a germanium substrate, a gallium arsenide substrate, or the like. The liquid crystal display panel is fabricated on a glass substrate, and even recently developed on a flexible plastic substrate. The substrate of the light-emitting diode is, for example, a sapphire substrate, an epitaxial substrate or the like. The package substrate and the printed circuit board are fabricated on an organic substrate. However these products Manufacturing methods include: thin film deposition, such as physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), etc., photolithography, electroplating, etching, thermal oxidation, Chemical mechanical polishing, spin coating, screen printing, etc. And each product is completed after dozens or hundreds of the above processes. In order to improve the yield and quality of these products, these processes need to be carried out in a very clean environment, such as a clean room, or a vacuum chamber. These products are very sensitive to dust particles and impurities. Especially in the process, different formulations, including liquid or gaseous, are often used. In order to prevent the residue of the formulation in the process from affecting the quality of the subsequent process, cleaning between the process and the process is required. . Conventionally, it is washed with a multi-channel wet chemical reaction and DI water, and then baked to ensure no residue. However, at present, there is no good detection method for whether there is residual after the above various substrate processes or the surface condition of the substrate is changed due to abnormal chemical liquid process, and it is usually detected in the subsequent process after the defect is generated, for example, for example, for example, The problem of photoresist peeling caused by residual acid. If it is possible to detect contamination or residue on the substrate before the process is implemented, remedial cleaning can avoid product defects and improve production yield.

Therefore, one aspect of the present invention is to provide an optical identification method and apparatus thereof, which can check whether a substrate is contaminated or left before a process is implemented to ensure the yield of the process.

According to an embodiment of the invention, an optical identification system is provided for inspecting a possible contaminant on a substrate, comprising: a carrying device, an optical identification device and a liquid spray device. The carrying device is configured to support the substrate, and the optical identification device is disposed above the carrying device for scanning an upper surface of the substrate. a liquid spray device disposed above the carrier device for generating a complex on the substrate A plurality of liquid particles, wherein the liquid particles have a predetermined size range and are adapted to be attached to the upper surface of the substrate at a predetermined pitch and shape at a predetermined spacing of the surface of the substrate to facilitate scanning by the optical identification device. When the substrate does not contain contaminants, the liquid particles adhere to the upper surface in an approximately spherical shape and have a predetermined size and spacing range; when the substrate contains contaminants, the liquid particles adhere to the upper surface in a film shape and irregularity. The shape or the non-predetermined size and the range of the pitch are spherical. It is determined by the optical identification system whether the liquid particles on the substrate exhibit an abnormal phenomenon to determine whether surface contamination occurs. The liquid particles can be removed by natural volatilization, blowing volatilization or heating and volatilization.

In accordance with another embodiment of the present invention, an optical identification method for inspecting a possible contaminant on a substrate is provided, comprising: providing a substrate on a carrier. A plurality of liquid particles are then produced by a vapor atomizing device, wherein the liquid particles each have a predetermined size range and are adapted to adhere to one of the upper surfaces of the substrate at a predetermined pitch and shape. The surface of the substrate is scanned by an optical identification device to capture at least one image and identify the size and spacing of the liquid particles in the image. When the substrate does not contain contaminants, the liquid particles adhere to the upper surface in an approximately spherical shape and have a predetermined size and spacing range; when the substrate contains contaminants, the liquid particles may exceed a non-predetermined size and spacing range.

In accordance with still another embodiment of the present invention, an optical identification system is provided for inspecting a possible contaminant on a substrate, including: an optical identification device and a liquid spray device. The optical identification device is disposed above the substrate for scanning an upper surface of the substrate. The liquid spray device is disposed above the substrate to generate a plurality of liquid particles, wherein the liquid particles are attached to the upper surface of the substrate for scanning by the optical identification device. And capturing at least one image and identifying liquid particles in the image. When the substrate does not contain contaminants, the liquid particles present a first shape in the image. When the substrate contains contaminants, the liquid particles assume a second form in the image, and the first form is different from the second form.

According to some embodiments of the present invention, the substrate may be a germanium substrate, a germanium substrate, a gallium arsenide substrate, a glass substrate, a flexible plastic substrate, a sapphire substrate, an epitaxial substrate, an organic substrate, or the like. The optical identification device not only recognizes the size, spacing and/or shape of the liquid particles, but also identifies the color of the liquid particles to identify whether they contain contaminants.

The advantages, spirits and features of the present invention will be described and discussed in detail by reference to the accompanying drawings. It is to be noted that, in order to make the invention more comprehensible, the appended drawings are only schematic representations, and the related dimensions are not shown in actual scale.

10‧‧‧Substrate

12,12’,208,208’‧‧‧ liquid particles

200‧‧‧ Optical Identification System

202‧‧‧Substrate

204‧‧‧Upper surface

206‧‧‧Liquid spray device

210‧‧‧Optical identification device

212‧‧‧ optical lens

214‧‧‧Photosensitive elements

216‧‧‧Image recognition device

220‧‧‧ Carrying device

302‧‧‧second heater

304‧‧‧First heater or cooler

402‧‧‧Web Edition

404‧‧‧ hole

D, D’‧‧‧ Diameter

S, S’‧‧‧ spacing

502, 504, 506‧ ‧ steps

1 is a schematic view of a surface of a substrate having liquid particles, in accordance with an embodiment of the present invention.

2 is a schematic diagram of an optical identification system in accordance with an embodiment of the present invention.

Figure 2A is an enlarged view of a portion of the area in Figure 2.

FIG. 3 is a schematic diagram of an optical identification system according to another embodiment of the present invention.

4 is a schematic diagram of an optical identification system in accordance with still another embodiment of the present invention.

FIG. 5 is a flow chart of an optical identification method according to an embodiment of the invention.

For the sake of the advantages and spirit of the invention, the spirit and the features may be more easily and clearly understood, and the detailed description and discussion will be made by way of example and with reference to the accompanying drawings. It is worth noting that this The embodiments are merely representative of the present invention, and the specific methods, devices, conditions, materials, and the like are not intended to limit the invention or the corresponding embodiments.

The optical identification system and method of the present invention can be applied to various substrates, For example, a semiconductor substrate corresponding to a semiconductor device (such as a germanium substrate, a germanium substrate, a gallium arsenide substrate, etc.), a glass substrate of a liquid crystal display panel, a flexible plastic substrate, a sapphire substrate of a light emitting diode, an epitaxial substrate, etc., a package substrate And organic substrates of printed circuit boards and the like.

Please refer to FIG. 1 , which shows a schematic diagram of liquid particles on the surface of the substrate. Taking the semiconductor substrate 10 as an example, for example, a germanium substrate, after some processes, is washed by deionized water, and it is desirable to remove the residue. For example, reactive reactant particles remaining on the surface after the deposition process, residual photoresist or etching solution after the lithography process, residual plating solution after plating, residual polishing liquid after polishing, etc., or during substrate transport Dust attached to the environment. These will form contaminants on the surface of the substrate 10, which will affect defects in subsequent processes, such as development defects in the lithography process. It is worth noting that when the sprayed liquid particles have a residual surface, these contaminant particles may affect some of the characteristics of these liquid particles, such as surface tension, color, and the like.

Taking pure water or deionized water, which is the most commonly used in the semiconductor process, as an example, when we spray steam on the substrate, a plurality of liquid particles 12 (i.e., deionized water particles) are generated on the substrate 10, and if the liquid particles 12 are present, Contaminants, this contaminant will fuse or mix with the liquid particles 12. Those skilled in the art will recognize that since the surface tension of water is very high, 72.75 mN/m, as long as the particle size is appropriate, an approximately spherical shape will appear on the substrate 10, as shown by the liquid particles 12 in the figure. Conversely, if the liquid particles 12' are fused or mixed with contaminants, the surface tension of the water may be destroyed by the contaminants. If the adhesion of the liquid particles 12' to the surface of the substrate is greater than the surface tension, the liquid particles 12' are made on the substrate. Can not appear spherical, but instead become a film, as shown in Figure 1 liquid particles 12' Shown. In particular, when the contaminant is an organic compound molecule, or a surfactant, such as an alcohol, an aldehyde, an acid, or an ester, it is soluble in the water particles, and the surface tension of the water particles is lowered. These organic compounds are often found in lithography processes, dielectric layer deposition, and polishing processes. Therefore, if some organic compounds remain after some processes, the above method can be used to discriminate whether the surface remains.

Similarly, in the case of pure water or deionized water, which is most commonly used in semiconductor manufacturing, when we spray steam on a substrate, a plurality of liquid particles 12 (i.e., deionized water particles) are generated on the substrate 10, and the substrate is chemically liquid during the manufacturing process. The process abnormality causes the contaminant to form a strong bond with the substrate. At this time, the contaminant does not fuse or mix with the liquid particle 12', but the surface energy of the substrate changes, which also causes the liquid particle size, spacing or morphology to change.

Please refer to FIG. 2 and FIG. 2A simultaneously. FIG. 2 is a schematic diagram of an optical identification system according to an embodiment of the present invention, and FIG. 2A is an enlarged view of a partial area of FIG. As shown, in some embodiments of the present invention, an optical identification system 200 is provided for inspecting a substrate 202 for residual contaminants (not shown), such as the organic compounds described above. The substrate 202 has an upper surface 204. The upper surface 204 may have formed some components (not shown) or stacked thin films (not shown) including active components such as field effect transistors (FETs) and passive components. Such as capacitors, resistors, inductors, etc., and the thin film layer includes a dielectric layer, an insulating layer, a metal layer, a wiring layer, a photoresist layer, and the like. Therefore, the material of the upper surface 204 may be metal, dielectric material, insulating material, organic compound, polymer, or the like. The substrate 202 can be inspected in the optical identification system of the present invention after it has been subjected to at least one process step and subjected to a suitable cleaning step. The optical identification system of the present invention includes a carrier 220 for carrying, supporting and holding the substrate 202. The carrier device 220 is, for example, an electrostatic chuck, or a vacuum chuck or the like. The liquid spray device 206 is disposed above the substrate 202, It is used to generate a plurality of liquid particles 208 attached to the upper surface 204 of the substrate 202. The liquid spray device 206 includes a steam spout device, an ultrasonic oscillating spray device, or a general nozzle spray device. Referring to FIG. 2A, in order to facilitate subsequent identification, the liquid particles 208 preferably have a predetermined size, such as a diameter D, respectively. The determination of the diameter D is related to the composition of the liquid particles 208 and the material adhesion of the liquid molecules 208 relative to the upper surface 204. In some embodiments, the preferred diameter D is from about 2 microns to about 2 mm, which is resolved according to optical identification. The degree can be adjusted by parameters such as spray parameters, substrate surface gas flow rate and substrate temperature. The liquid particles 208 are disposed on the upper surface 204 at a predetermined interval S, and are vented to the vapor to condense to generate liquid particles. The pitch S is related to the liquid type, the substrate temperature and the surface state of the substrate, and can generate liquid particles having a small pitch; The other active bead generating devices can dynamically adjust the spacing S, but when the spacing is too small, the liquid bead overlap problem will affect the inspection. In some embodiments, the optical identification system of the present invention can be configured in a clean room or a clean chamber.

As described above, when the liquid particles 208 do not contain contaminants or when there is no abnormal element bonding on the substrate, the adhesion to the upper surface 204 is approximately spherical, and when the liquid particles 208 contain contaminants, or there is an abnormality on the substrate. When the element is bonded, it changes due to surface tension and adhesion, and adheres to the upper surface 204 as a film (as shown by the liquid particles 208' in FIG. 2). Since the liquid particles 208 and 208' are different in shape, they can be identified by an optical identification device 210. In some embodiments of the invention, optical identification device 210 includes an optical lens 212, a charge coupled component 214 (CCD), and an image recognition device 216. The charge coupled device 214 scans the upper surface 204 of the substrate 202 through the optical lens 212 to capture an image containing an image of the liquid particles 208, 208' on the upper surface 204. The image recognition device 216 is configured to recognize the shape of the liquid particles 208, 208' in the image, such as a spherical shape or an aspherical shape (film shape). Those skilled in the art should know that image recognition equipment The device generally includes a processor, a memory, and an input/output device, etc., can receive images, perform calculation and recognition, and then output the identification result, and the steps can be completed by using firmware or software, which is a commonly used technology. Therefore, it will not be repeated here. In some embodiments of the present invention, when the image recognition device recognizes that the liquid particles 208' in the image are aspherical, that is, irregularly shaped, it can be concluded that the surface of the substrate 202 remains or is contaminated. Subsequent remedial cleaning can be performed.

It should be noted that the resolution of the optical identification device 210 needs to be able to accurately detect the distance S between the liquid particles 208' and the size D. Therefore, it is necessary to select a photosensitive element 214 with a suitable degree of identification (such as a charge coupled device CCD or a complementary type). Metal-oxide layer-semiconductor CMOS), and the magnification of the optical lens 212. In order to improve the accuracy of optical recognition, the size and properties of the various substrates 202 are also considered. The scanning method of the optical recognition device 210 for the upper surface 204 may be stepped by a stepper method, and the partial regions are scanned one by one in a matrix. The magnification of the optical lens 212 should also take into account the size of the substrate, so the magnification can be greater than 1, less than 1 or equal to 1. Furthermore, it should be noted that the effect of contaminants on the liquid particles 208' may, in addition to changing the surface tension, alter the reflective or refractive properties of the surface of the liquid particles 208'. In some embodiments, the contaminated liquid particles 208', and the uncontaminated liquid particles 208, may exhibit different colors in the image by appropriate light illumination. Therefore, the optical recognition device 210 can also determine whether the upper surface 204 is contaminated by recognizing the color of the liquid particles in the image. In addition, as described above, the substrate 202 is strongly bonded to the substrate 202 due to an abnormal chemical liquid process during the manufacturing process. At this time, the contaminant does not fuse or mix with the liquid particles 208', but the surface of the substrate 202 Can change, also causes changes in the size, spacing (due to abnormal polymerization) or morphology (changes in adhesion) of the liquid particles. Therefore, the optical identification device 210 can also recognize the size, spacing or form of the liquid particles in the image. It is judged whether or not the upper surface 204 is contaminated.

Please refer to FIG. 3, which is a schematic diagram of an optical identification system according to another embodiment of the present invention. The same reference numerals in the drawings represent similar elements or devices. For the function and detailed description, please refer to the above description, and no further details are provided herein. In some embodiments, in order to evenly distribute and control the size of the liquid particles 208, a first heater or cooler 304 may be added to the carrier 220 to moderately bake or cool the substrate 202. The liquid particles 208 on the surface 204 are subjected to moderate evapotranspiration and cooling as needed to maintain spacing and control particle size. In order to improve the identification accuracy and prevent the liquid particles 208 from adhering to the lens and affecting the image capturing, a second heater 302 may be disposed around the periphery of the optical lens 212 to bake the optical lens to adhere the liquid particles thereon (not Show) evapotranspiration.

Please refer to FIG. 4, which is a schematic diagram of an optical identification system according to still another embodiment of the present invention. The same reference numerals in the drawings represent similar elements or devices. For the function and detailed description, please refer to the above description, and no further details are provided herein. In some embodiments, another method for uniformly distributing liquid particles 208 and controlling its size is to configure a web between liquid spray device 206 and upper surface 204 when liquid spray device 206 produces liquid particles 208. The screen 402 has a plurality of holes 404, and the diameter D' of the holes 404 is slightly larger than the diameter D of the predetermined liquid particles 208, so that the liquid particles 208 can be easily passed through to the upper surface 204. The spacing S' of the holes 404 is the same as the spacing S of the predetermined liquid particles 208, so that the liquid particles 208 produced by the liquid atomizing device 206 can be evenly distributed on the upper surface 204. The material of the screen 402 may be selected from a hydrophobic material such that the liquid particles 208 are not easily attached thereto, and the screen 402 may be in close proximity to the upper surface 204, so that the liquid particles 208 are less likely to drift between the screen 402 and the upper surface 204. Of course, the screen 402 will be removed before the subsequent optical identification device 210 performs scanning.

Referring to FIG. 5, a flow chart of an optical identification method according to an embodiment of the invention is shown. In some embodiments, the steps of the optical identification method of the present invention are as follows. First, as shown in step 502, the substrate is provided on a carrier. A plurality of liquid particles are then produced by a liquid spray device as in step 504. The liquid particles respectively have a predetermined size and are attached to the upper surface of one of the substrates at a predetermined interval from each other. Then, in step 506, an optical recognition device is used to scan the upper surface of the substrate to capture at least one image and identify liquid particles in the image. When the substrate does not contain contaminants, the liquid particles adhere to the upper surface to have an approximately spherical shape, and when the substrate contains contaminants, the liquid particles adhere to the upper surface to form an aspherical shape or a film shape. As described above, in step 506, if the surface energy of the substrate is changed due to contaminants or contamination, the image of the liquid particles may be differently displayed, such as different colors, changes in liquid particle size, spacing, or morphology, and may also be by liquid. Particle color, size, spacing, and shape identification are used to determine whether there is contamination. Additionally, as noted above, the screen as previously described may be added in step 504 such that the liquid particles may be more evenly distributed and the screen removed prior to step 506. It should be noted that although the liquid particles are exemplified by pure water or deionized water in the above embodiments, those skilled in the art should know that other liquids can be used as the liquid according to the upper surface material and the type of the contaminant. Particles, such as organic solvents, can be identified by optical identification techniques as long as the liquid particles are mixed or fused with contaminants, or the contaminants change the surface properties of the substrate to produce significant changes in appearance, such as shape, size, spacing, color, morphology, etc. To determine if there is pollution.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Although the invention has been disclosed in an embodiment, However, it is not intended to limit the invention, and any person skilled in the art can make various changes and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is attached to the patent application. The scope is defined.

208,208’‧‧‧ liquid particles

210‧‧‧Optical identification device

200‧‧‧ Optical Identification System

212‧‧‧ optical lens

202‧‧‧Substrate

214‧‧‧Charge-coupled components

204‧‧‧Upper surface

216‧‧‧Image recognition device

206‧‧‧Liquid spray device

220‧‧‧ Carrying device

Claims (10)

An optical identification system for inspecting a possible contaminant on a substrate, comprising: a carrying device configured to support the substrate; an optical identification device disposed above the carrying device for scanning one of the substrates An upper surface; and a liquid spray device disposed above the carrier for generating a plurality of liquid particles, wherein the liquid particles each have a predetermined size and are adapted to be attached to the substrate at a predetermined interval from each other The surface is scanned by the optical identification device. When the upper surface of the substrate does not contain the contaminant, the image exhibits a first form; when the upper surface of the substrate contains the contaminant, The image is in a second form, wherein in the image of the first form, the liquid particles are attached to the upper surface in an approximately spherical shape and have the predetermined size and the predetermined spacing range; In the image, the liquid particles are attached to the upper surface in a spherical shape, irregular shape or a spherical shape of a non-predetermined size and a range of pitch. The optical identification system of claim 1, wherein the substrate is selected from the group consisting of a semiconductor substrate, an LED substrate, a glass substrate, a package substrate, and a circuit board. The optical identification system of claim 1, wherein the image of the first form and the liquid particles of the second form of the image exhibit different colors. The optical identification system of claim 1, wherein the carrying device further comprises a first heater for heating the substrate. The optical identification system of claim 1, wherein the carrying device further comprises a cold A device for cooling the substrate. The optical identification system of claim 1, wherein the optical identification device further comprises: an optical lens; a photosensitive element, wherein the photosensitive element scans the upper surface of the substrate through the optical lens to capture an image And an image recognition device for identifying the size, shape, spacing or color of the liquid particles in the image. The optical identification system of claim 6, further comprising a heater disposed on a periphery of the optical lens for maintaining the drying of the optical lens. The optical identification system of claim 1, wherein the liquid spray device comprises a vapor ejector device, an ultrasonic oscillating spray device, or a general nozzle spray device. The optical identification system of claim 1, further comprising a screen disposed between the upper surface of the substrate and the liquid spray device when the liquid spray device generates the liquid particles, and The screen is removed while the optical identification device is scanning, wherein the screen further includes a plurality of holes, wherein the holes are approximately larger than the predetermined size, and the holes are separated from each other by the predetermined spacing. The optical identification system of claim 1, wherein the liquid particles comprise deionized water particles, pure water particles or organic solvent particles, and the like.