U-shaped light source for wafer side edge detection

Abstract

The utility model provides a U-shaped light source for wafer side edge detection, which comprises an illumination light source which comprises a plurality of groups of light bars. The plurality of condensing lenses are arranged in front of the plurality of groups of light bars; the light uniformizing sheet is arranged in front of the condensing lenses, and the section of the light uniformizing sheet is in a U shape; the shell comprises a U-shaped part and a vertical part, and the vertical part is connected with the dodging sheet; the dodging sheet is the inner surface of the U-shaped light source, and the shell is the outer surface of the U-shaped light source; the illumination light source and the plurality of condensing lenses are arranged in an area surrounded by the shell and the dodging sheet; light through holes are formed in the center of the shell and the center of the dodging piece. According to the U-shaped light source for wafer side edge detection provided by the utility model, the mounting angles of the four groups of light bars are different, so that the compatibility of different chamfer shapes is improved, and the uniformity of a bright field detection background is remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor equipment especially relates to a U type light source for wafer side edge detection. BACKGROUND

[0002] The defect of wafer has the remarkable influence to semiconductor device, and the wafer of existence defect flows into subsequent process will have the serious influence to product performance and yield. Automated optical inspection (AOI) technology as an important detection method, has the extensive application in wafer detection.

[0003] From the process of wafer edge chamfer, there are seven forms at present, including arc chamfer, bevel chamfer, V chamfer, U chamfer, rectangular chamfer, wave-shaped chamfer and sawtooth chamfer. For ordinary illumination light source, the background of different chamfer forms imaging cannot achieve uniform effect. Taking bright field detection as an example, dark area will be produced in partial area, and the detection effect in dark area will decrease obviously. SUMMARY

[0004] In view of partial or all problems in prior art, the utility model provides a U type light source for wafer side edge detection, comprising:

[0005] Illumination light source, the illumination light source includes multiple groups of lamp strips, and the multiple groups of lamp strips are configured to emit illumination light beams;

[0006] Multiple condenser lenses, the multiple condenser lenses are arranged before the multiple groups of lamp strips, and the condenser lenses are used for reducing the divergence angle of the illumination light beams;

[0007] Uniform light sheet, the uniform light sheet is arranged before the multiple condenser lenses, and the uniform light sheet is in U type; and

[0008] Shell, the shell includes U type part and vertical part, and the vertical part is connected with the uniform light sheet;

[0009] The uniform light sheet is the inner surface of the U type light source, the shell is the outer surface of the U type light source, the illumination light source and the multiple condenser lenses are arranged in the area surrounded by the shell and the uniform light sheet, and the center of the shell and the uniform light sheet is arranged with light transmission hole.

[0010] Further, the illumination light source includes four groups of lamp strips, each group of lamp strips includes two lamp strips; and / or

[0011] The two lamp strips in each group of lamp strips are symmetrically arranged according to the position of the light transmission hole.

[0012] Further, the four groups of light bars are arranged at 6°, 50°, 80° and 100° angles respectively with respect to the direction parallel to the center line of the light hole.

[0013] Further, the length of each light bar is 40-60 mm; and / or

[0014] Each light bar comprises 5-7 lamp beads; and / or

[0015] The lamp beads are blue light LED lamp beads, and the wavelength range of the light beams emitted by the blue light LED lamp beads is 420-500 nm.

[0016] Further, the four groups of light bars comprise a first group of light bars, a second group of light bars, a third group of light bars and a fourth group of light bars.

[0017] The four groups of light bars are arranged according to the wafer chamfer;

[0018] The first group of light bars is used for illuminating the vertical part of the wafer side edge, the second group of light bars is used for illuminating the first chamfer adjacent to the vertical part, the third group of light bars is used for illuminating the area adjacent to the first chamfer, and the fourth group of light bars is used for illuminating the area where the wafer chamfer ends and the wafer surface area.

[0019] Further, the power of each group of light bars is controlled individually; and / or

[0020] The maximum power of each group of light bars is within 3 W.

[0021] Further, the maximum power of the second group of light bars, the third group of light bars and the fourth group of light bars is the same; and / or

[0022] The maximum power of the first group of light bars is less than that of the second group of light bars.

[0023] Further, the condenser lens is a cylindrical mirror; and / or

[0024] The length of each condenser lens is 40-60 mm.

[0025] Further, the light uniformizing sheet is a glass light uniformizing sheet or an acrylic light uniformizing sheet or a polycarbonate light uniformizing sheet; and / or

[0026] The thickness of the light uniformizing sheet is not more than 2 mm.

[0027] Further, the shell is a stainless steel shell or an aluminum alloy shell or a magnesium alloy shell or a titanium alloy shell or a rubber shell or a polypropylene shell or a polyethylene shell or a polyvinyl chloride shell.

[0028] Compared with the prior art, the utility model has the following advantages:

[0029] 1. The U-shaped light source for wafer side edge detection, the mounting angles of the four groups of lamp strips are different, the compatibility of different chamfer shapes is improved, and the uniformity of the bright field detection background is significantly improved.

[0030] 2. The U-shaped light source for wafer side edge detection, the power of the four groups of lamp strips can be independently controlled, and the background brightness difference between different shapes and different imaging areas can be maximally compensated.

[0031] 3. The U-shaped light source for wafer side edge detection, the lamp beads of the four groups of lamp strips adopt blue LEDs, the blue light wavelength is shorter, and the imaging resolution is higher. BRIEF DESCRIPTION OF DRAWINGS

[0032] To further illustrate the above and other advantages and features of the embodiments of the present application, more specific description of the embodiments of the present application will be presented with reference to the accompanying drawings. It can be understood that these drawings only depict typical embodiments of the present application, and therefore should not be considered as limiting the scope thereof. In the drawings, for the sake of clarity and conciseness, the same or corresponding components will be denoted by the same or similar reference numerals.

[0033] Figure 1 shows a cross-sectional schematic view of the U-shaped light source for wafer side edge detection of one embodiment of the present application; and

[0034] Figure 2 shows a schematic view of a lamp strip of one embodiment of the present application. DETAILED DESCRIPTION

[0035] In the following description, the present application is described with reference to the embodiments. However, those skilled in the art will realize that the embodiments can be implemented without one or more of the specific details or with other alternative and / or additional methods or components. In other instances, well-known structures or operations are not shown or described in detail in order to avoid obscuring the application point of the present application. Similarly, for the purpose of explanation, specific numbers and configurations are set forth in order to provide a thorough understanding of the embodiments of the present application. However, the present application is not limited to these specific details.

[0036] In the present application, unless specifically indicated, "arranged on" and "arranged above" do not exclude the presence of an intermediate object between them. In addition, "arranged on or above" only represents the relative positional relationship between the two components, and in some cases, such as after reversing the product direction, it can also be converted to "arranged below or below", and vice versa.

[0037] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to all of the same embodiment.

[0038] It should be noted that the embodiments of this utility model use the terms "comprising", "including", "having", "containing" and / or "comprising", which, when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0039] In this specification, unless otherwise specified, "first" and "second" are used only for distinguishing descriptions, do not contain differences in size, and should not be construed as indicating or implying relative importance.

[0040] In this specification, the quantifiers “multiple” and “more” refer to one or more elements.

[0041] The present invention will be further described below with reference to the accompanying drawings of the embodiments.

[0042] Figure 1 A cross-sectional schematic diagram of a U-shaped light source for wafer side inspection according to an embodiment of the present invention is shown. Figure 1 As shown, the U-shaped light source for wafer side inspection includes an illumination source, multiple focusing lenses 2, a light-diffusing sheet 3, and a housing 4. The illumination source includes four sets of light strips configured to emit illumination beams. The four sets of light strips include a first set of light strips 11, a second set of light strips 12, a third set of light strips 13, and a fourth set of light strips 14. Each set of light strips includes two light strips, which are symmetrically arranged according to the position of the light-transmitting aperture. Figure 1 As shown, the light-diffusing plate 3 is the inner surface of the U-shaped light source, and the outer shell 4 is the outer surface of the U-shaped light source. The lighting source and multiple condensing lenses are arranged in the area surrounded by the outer shell 4 and the light-diffusing plate 3. A light-passing hole 5 is arranged in the center of the outer shell 4 and the light-diffusing plate 3.

[0043] Figure 2 A schematic diagram of a light strip according to an embodiment of the present invention is shown. Figure 2As shown, one light bar includes 5-7 lamp beads 111. In an embodiment of the present application, the length of each light bar is 40-60 mm. Common LEDs have three colors of red, blue and green light, among which the wavelength of blue light is the shortest, and according to the calculation method of diffraction limit, the imaging Airy disk diameter is the smallest, so its imaging resolution is the highest. Under the same conditions, it is also stronger in the ability to distinguish small defects, so blue light LED is selected for the LED lamp bead. In an embodiment of the present application, the wavelength range of the light beam emitted by the blue light LED lamp bead is 420-500 nm.

[0044] For the complex chamfering of the wafer 10, the illumination of the four groups of light bars is targeted. In an embodiment of the present application, the first group of light bars 11, the second group of light bars 12, the third group of light bars 13 and the fourth group of light bars 14 are arranged at angles of 6°, 50°, 80° and 100°, respectively, with respect to the direction parallel to the center line of the light hole. Different angles are realized by the reference surface of the shell mounting position. According to the chamfering of the wafer, four groups of light bars are arranged. The first group of light bars 11 is mainly aimed at the side edge of the wafer, and the designed inclination angle is that as many light rays as possible are directly incident on the side edge part, so that as many scattered light as possible passes through the light hole into the lens, reserving the maximum adjustment amount for the imaging brightness consistency of different regions, and the angle settings of the other three groups of light bars are similar. The first group of light bars 11 is used to illuminate the vertical part of the side edge of the wafer 10, the second group of light bars 12 is used to illuminate the first chamfer adjacent to the vertical part, the third group of light bars 13 is used to illuminate the region adjacent to the first chamfer, and the fourth group of light bars 14 is used to illuminate the region where the wafer chamfering ends and the wafer surface region. Since the angles of chamfering of each region are different, the reflection or scattering directions are also different, and after imaging by the camera, four groups of light bar imaging regions are formed. Changing the power of the four groups of light bars changes the brightness of the corresponding region, and the imaging brightness of different regions can be made consistent through power adjustment. In an embodiment of the present application, the power of each group of light bars or each light bar can be controlled individually, and the maximum power of each group of light bars is within 3W. In an embodiment of the present application, the maximum power of the second group of light bars 12, the third group of light bars 13 and the fourth group of light bars 14 is the same, such as 2.6W; the maximum power of the first group of light bars 11 is less than that of the second group of light bars 12, such as 1.7W. The power of the four groups of light bars can be independently controlled, which helps to reduce the difference in imaging brightness of different regions, makes the imaging background of the wafer edge part uniform, is conducive to the highlighting of edge collapse defects, and reduces the probability of missed detection and over detection.

[0045] The initial divergence angle of the LED is usually large, which is not conducive to targeted illumination of different regions, so a lens needs to be added in front of the LED. For example Figure 1As shown, multiple condenser lenses 2 are arranged in front of the multiple sets of light strips. The condenser lenses 2 are used to reduce the divergence angle of the illumination beam and increase the illuminance per unit area. In one embodiment of this utility model, the condenser lens 2 can be a cylindrical mirror, and the length of each condenser lens is 40mm-60mm.

[0046] like Figure 1 As shown, the light-diffusing sheet 3 is arranged in front of multiple condenser lenses 2, and the light-diffusing sheet 3 is U-shaped. In one embodiment of this utility model, the light-diffusing sheet 3 is a glass light-diffusing sheet, an acrylic light-diffusing sheet, or a polycarbonate light-diffusing sheet, and the thickness of the light-diffusing sheet 3 does not exceed 2mm.

[0047] like Figure 1 As shown, the outer casing 4 includes a U-shaped portion and a vertical portion, the vertical portion being connected to the light-diffusing plate. In one embodiment of this invention, the outer casing 4 is a stainless steel casing, an aluminum alloy casing, a magnesium alloy casing, a titanium alloy casing, a rubber casing, a polypropylene casing, a polyethylene casing, or a polyvinyl chloride casing. In one embodiment of this invention, to ensure that the light beam is not affected by external stray light, the outer casing 4 includes a light-shielding material.

[0048] The U-shaped light source provided by this utility model for wafer side inspection has four sets of light bars installed at different angles, which improves compatibility with different chamfer shapes and significantly improves the uniformity of the background in bright-field inspection. The power of the four sets of light bars can be controlled independently, which can compensate for the background brightness differences between different shapes and imaging areas to the greatest extent. The lamps of the four sets of light bars use blue LEDs, and the blue light has a shorter wavelength, resulting in higher imaging resolution.

[0049] Although various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited to the exemplary embodiments disclosed above, but should be defined only according to the technical solutions and their equivalents.

Claims

1. A U-shaped light source for wafer side edge detection, characterized by, The U-shaped light source for wafer side edge detection comprises: a lighting source comprising a plurality of groups of light bars configured to emit a lighting beam; a plurality of condenser lenses arranged in front of the plurality of groups of light bars, the condenser lenses being used to reduce the divergence angle of the lighting beam; a light homogenizing sheet arranged in front of the plurality of condenser lenses, the light homogenizing sheet being in a U shape; and a housing comprising a U-shaped portion and a vertical portion, the vertical portion being connected to the light homogenizing sheet; the light homogenizing sheet is an inner surface of the U-shaped light source, and the housing is an outer surface of the U-shaped light source; the lighting source and the plurality of condenser lenses are arranged in an area enclosed by the housing and the light homogenizing sheet; and a light transmission hole is arranged at the center of the housing and the light homogenizing sheet.

2. The U-shaped light source for wafer side edge detection according to claim 1, wherein: the lighting source comprises four groups of light bars, each group of light bars comprising two light bars; and / or the two light bars in each group of light bars are symmetrically arranged according to the position of the light transmission hole.

3. The U-shaped light source for wafer side edge detection according to claim 2, wherein: the four groups of light bars are arranged at angles of 6°, 50°, 80° and 100°, respectively, with respect to the direction parallel to the center line of the light transmission hole.

4. The U-shaped light source for wafer side edge detection according to claim 2, wherein: each light bar has a length of 40-60 mm; and / or each light bar comprises 5-7 light beads; and / or the light beads are blue light LED light beads, and the wavelength range of the light beams emitted by the blue light LED light beads is 420-500 nm.

5. The U-shaped light source for wafer side edge detection according to claim 2, wherein: the four groups of light bars comprise a first group of light bars, a second group of light bars, a third group of light bars and a fourth group of light bars; the four groups of light bars are arranged according to the wafer chamfer; the first group of light bars is used to illuminate the vertical part of the wafer side edge, the second group of light bars is used to illuminate the first chamfer adjacent to the vertical part, the third group of light bars is used to illuminate the area adjacent to the first chamfer, and the fourth group of light bars is used to illuminate the area where the wafer chamfer ends and the wafer surface area.

6. The U-shaped light source for wafer side edge detection according to claim 2, wherein: the power of each group of light bars is controlled individually; and / or the maximum power of each group of light bars is within 3 W.

7. The U-shaped light source for wafer side edge detection according to claim 5, wherein: the maximum power of the second group of light bars, the third group of light bars and the fourth group of light bars is the same; and / or the maximum power of the first group of light bars is less than the maximum power of the second group of light bars.

8. The U-shaped light source for wafer side edge detection according to claim 1, wherein: the condenser lenses are cylindrical lenses; and / or each condenser lens has a length of 40-60 mm.

9. The U-shaped light source for wafer side edge detection according to claim 1, wherein: the light homogenizing sheet is a glass light homogenizing sheet or an acrylic light homogenizing sheet or a polycarbonate light homogenizing sheet; and / or The thickness of the light homogenizing sheet is not more than 2mm.

10. The U-shaped light source for wafer side edge detection according to claim 1, wherein, The shell is a stainless steel shell or an aluminum alloy shell or a magnesium alloy shell or a titanium alloy shell or a rubber shell or a polypropylene shell or a polyethylene shell or a polyvinyl chloride shell.

Images