TWI780909B - Imaging device for detecting wafer surface and imaging equipment thereof - Google Patents

Abstract

This application discloses an imaging device for detecting wafer surface and an imaging equipment thereof. The imaging device is arranged on the carrier and includes a support seat, a light irradiating portion and an image capturing portion. The carrier makes the wafer have an inclination angle based on a first axial direction. The image capturing portion includes a first bracket, a second bracket, a track and a camera movable on the track. The first bracket is erected on the carrier, a front end of the second bracket is pivotally connected to a base of the first bracket, and an extension arm of the second bracket is parallel to the horizontal plane. The second bracket is centered on the front end so that the extension arm has a movable range that sweeps across the surface of the carrier. The position of the extension arm parallel to the first axial direction is defined as a boundary of the movable range, and from the boundary to the direction of the light irradiated portion, a range of movement between 0 degrees and 50 degrees is arranged. Therefore, the surface uniformity of solder bumps on the wafer can be effectively detected.

Description

Imaging device and imaging equipment for detecting wafer surface

The present invention relates to an imaging device and imaging equipment thereof. For wafers with metal balls implanted on the surface, more particularly to an imaging device and imaging equipment for detecting the wafer surface.

With the evolution of semiconductor technology, the trend of miniaturization of integrated circuits has led to the continuous development of component packaging and construction technology. The electrical connection method between electronic components has evolved from wire bonds to ball planting. For example: Implant the solder ball.

The technology of bumping is to make metal balls on the wafer by thin film, yellow light, electroplating process or printing technology, and then melt the metal balls in the back-end integrated circuit packaging process, and then connect with the solder pads on the circuit board for encapsulation. For example, Wafer Level Chip Size Package (WLCSP) technology uses this method of planting balls on the wafer, which can greatly reduce the volume of the integrated circuit package.

Based on the requirements of semiconductor packaging precision, the spheres implanted on the wafer need to have certain uniform conditions. Response characteristics of the performance. Therefore, the surface state of the spheres implanted on the wafer needs to be correctly obtained for subsequent ball placement quality judgment.

One object of the present invention is to provide an effective imaging device and imaging equipment for the surface state of the spheres implanted on the wafer.

Another object of the present invention is to improve the detection efficiency of the ball surface state of the ball planted on the wafer.

In order to achieve the above-mentioned purpose and other purposes, the present invention proposes an imaging device for detecting the surface of a wafer, which is installed on a stage and is used for imaging a wafer implanted with a plurality of metal balls. The imaging device includes : a bearing seat, a light irradiation part and an image taking part. The carrying seat is used to carry the wafer, and based on a rotation range in the first axis, the wafer has an inclination angle compared with a horizontal plane. The light irradiating part is used for providing an irradiating light along the second axis and irradiating toward the wafer. The image-taking part includes: a first bracket, a second bracket, a track and a camera movable on the track, the first bracket is erected on the platform, and a front end of the second bracket is pivotally connected to the first A base of a bracket and the extension arm of the second bracket is parallel to the horizontal plane, the track is connected between a top seat of the first bracket and a rear end of the second bracket, the second bracket is connected by the The front end is the center of a circle so that the extension arm has a movable range to sweep across the surface of the stage. Wherein, the first axis is perpendicular to the second axis, and the position where the extension arm of the second bracket is parallel to the first axis is defined as the boundary of the movable range, and the movable range is defined as from The boundary has a moving range between 0° and 50° toward the direction of the light irradiation portion.

According to an embodiment of the present invention, the track may be an arc track, and the track is used to limit the included angle between an imaging axis of the camera and the horizontal plane within 15 degrees to 60 degrees.

According to an embodiment of the present invention, the inclination angle can be limited between -10 degrees and 10 degrees.

According to an embodiment of the present invention, the front end of the second support as the center of a circle can be disposed under the carrier seat and located on the central axis of the wafer.

According to an embodiment of the present invention, the image-taking unit may further include an indicating unit, a first limiting unit, and a second limiting unit arranged on the stage, and the first limiting unit and the second limiting unit Used to limit the movement range of the second bracket, the indicating unit is configured as an arc to indicate between the first limiting unit and the second limiting unit, and the indicating unit is provided with a scale to indicate the second The angle between the bracket and the first axis.

According to an embodiment of the present invention, the light irradiation part may include a light source unit and a diffusion unit, and the diffusion unit is a Fresnel lens.

According to an embodiment of the present invention, the carrier may have a rotation axis for rotating the wafer.

In order to achieve the above-mentioned purpose and other purposes, the present invention reproposes a kind of imaging equipment for detecting the surface of the wafer, including a second light irradiation part and an imaging device as described above, the imaging part of the imaging device The first bracket has a rotational degree of freedom around the bearing seat of the imaging device, and the movable range of the second bracket of the imaging part of the imaging device includes a plurality of limited intervals, and each of the limited intervals covers the bearing Different surface areas on the table surface, the second light irradiation part is arranged on the stage and used to provide irradiation light along the second axis and toward the wafer, the second light irradiation part is the same as that of the imaging device The light irradiation parts are disposed opposite to each other.

Accordingly, the imaging device for detecting the surface of the wafer and the imaging equipment thereof disclosed in the present invention can correctly obtain images implanted on the wafer under the configuration that the imaging position and the light emitting position of the irradiating light are on the same side. The surface state of the metal ball, thereby improving the detection efficiency.

100: bearing seat

200: Light irradiation department

200': The second light irradiation part

210: Light source unit

220: Diffusion unit

300: Image acquisition department

310: the first bracket

311: base

312: top seat

320: second bracket

321: front end

322: Backend

323: extension arm

330: track

340: camera

350: indicating unit

351: The first limit unit

352: The second limit unit

400: Wafer

500: carrier

L1: first axis

L2: second axis

Z: The axis perpendicular to the first axis and the second axis

I ₁ : image capture direction

I ₂ : Projection of I ₁ on the horizontal plane

θ ₁ : Inclination angle

θ ₂ : the angle between I ₂ and the first axis L1

θ ₃ : the angle between I ₁ and the horizontal plane

[FIG. 1] is a partial schematic diagram of an image pickup device for inspecting the surface of a wafer according to an embodiment of the present invention.

[ Fig. 2 ] is a three-dimensional schematic diagram of an imaging device for inspecting a wafer surface in an embodiment of the present invention.

[ Fig. 3 ] is a schematic top view of an imaging device for inspecting a wafer surface in another embodiment of the present invention.

[ FIG. 4 ] is a schematic top view of another operation of the embodiment in FIG. 3 .

In order to fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments and accompanying drawings, as follows:

In this document, the term "a" or "an" is used to describe a unit, component, structure, device, module, system, location or region, etc. This is done for convenience of description only and to provide a general sense of the scope of the invention. Accordingly, such description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is otherwise meant.

In this document, the terms "comprising, including, having" or any other similar terms are not limited to the elements listed herein, but may include other elements listed but generally inherent in the unit, component, structure, device, module, system, part or area.

In this article, the words "first" or "second" and similar ordinal numbers described are used to distinguish or refer to the same or similar elements, structures, parts or regions, and do not necessarily imply these elements , the spatial order of structures, parts or regions. It should be understood that in some cases or configurations, ordinal terms may be used interchangeably without affecting the practice of the present invention.

There are as many as one million metal spheres implanted on the wafer. In the past, large-scale manual visual inspection was used for inspection, but this method could neither improve the detection efficiency nor effectively reveal the defects on the metal spheres. Metal balls that are correctly implanted into the wafer usually have at least a smooth surface, and metal balls with defects, such as: balls with poor parameters related to ball formation, resulting in white spots and fogging on the surface, are easy to be melted and connected in the subsequent process. Finally, it will affect the electrical conductivity characteristics and reduce the quality.

Therefore, the defects of the metal sphere must be effectively visualized. Please refer to FIG. 1 , which is a partial schematic diagram of an imaging device for inspecting the surface of a wafer according to an embodiment of the present invention. As shown in Figure 1, in order to improve the detection efficiency of the spherical surface state of the ball planted on the wafer, in this embodiment, a specific arrangement is made to the position of the image taking and the light emitting position of the irradiating light, thereby improving the defects in the image. The degree of contrast between the part and the normal part allows blemishes to be effectively revealed.

In FIG. 1 , the image capturing device includes: a light irradiation unit 200 and a camera 340 . The light irradiation unit 200 is used to provide irradiation light to the wafer 400 , and the camera 340 is used to take images of the wafer 400 to provide image data for subsequent defect determination. As shown in FIG. 1 , the wafer 400 has an inclination angle θ1 compared to the horizontal plane, and the horizontal plane is a common plane formed by two mutually perpendicular axes, the first axis L1 and the second axis L2 . The first axis L1 is a rotation axis of the wafer 400 , for example, the wafer 400 can be tilted at an angle θ ₁ by rotating the platform carrying the wafer 400 around the first axis L1 . The second axis L2 is the irradiation direction of the irradiation light provided by the light irradiation unit 200 .

In the configuration of FIG. 1 , and under the condition that the positional relationship of the light irradiation part 200 relative to the wafer 400 is fixed, the orientation direction of the camera 340 is configured within a certain range, which can provide a relatively high degree of accuracy for the metal balls on the wafer 400. Good image resolution, that is, a high degree of contrast between the flawed part and the normal part on the surface of the metal ball. The projection amount of the imaging direction I ₁ of the camera 340 on the horizontal plane is I ₂ , based on the first axis L1, when the angle θ ₂ between the projection amount I ₂ and the first axis L1 is limited to 0°~50° When between degrees, the metal balls on the wafer 400 in the image captured by the camera 340 can be presented with a better contrast, which is helpful for the visualization and determination of defects.

Wherein, the included angle θ3 between the image capturing direction _I1 of the camera ₃₄₀ and the horizontal plane can be limited between 15 degrees and 60 degrees, and the aforementioned configuration conditions can be combined to provide better image capturing results. The light irradiation unit 200 may include a light source unit 210 and a diffuser unit 220 , the diffuser unit 220 is used to make the light emitted by the light source unit 210 form parallel light (parallel to the second axis L2 ) irradiated to the wafer 400 . The diffusion unit 220 is, for example, a Fresnel lens.

Based on the fact that the camera 340 and the light irradiation unit 200 are arranged on the same side (on the side of the first axis L1), and the inclination angle θ ₁ of the wafer 400 relative to the irradiation light, this makes the camera 340 on the substrate of the wafer 400 The reflected light formed corresponding to the irradiated light is equivalent to being excluded, and it is difficult to enter the camera 340 disposed on the same side as the light irradiating unit 200 . Therefore, such a configuration allows most of the information entering the camera 340 to come from the surface reflected light information of the ball-mounted spheres on the wafer 400, greatly reducing the interference from the reflected light information from the substrate of the wafer 400, and subsequent defect determination will be more accurate. .

Next, please refer to FIG. 2 , which is a three-dimensional schematic diagram of an imaging device for inspecting a wafer surface in an embodiment of the present invention. The imaging device used for detecting the surface of the wafer is arranged on the stage 500 for The wafer 400 implanted with a plurality of metal balls is imaged. The imaging device includes: a bearing base 100 , a light irradiation unit 200 and an imaging unit 300 . The imaging device of this embodiment provides a configuration in which the surface uniformity of the metal balls implanted on the wafer can be effectively detected, and the spheres with a higher degree of contrast can be efficiently obtained through the operation of the imaging device Image data of the surface state.

The carrier 100 is used for carrying the wafer 400 under test. The carrier 100 can make the wafer 400 have an inclination angle compared with the horizontal plane based on a rotation range along the first axis L1 (see FIG. 1 at the same time). The inclination angle is used to make the surface of the wafer 400 slightly face the light irradiation part 200 , and further, the inclination angle with the second axis L2 can be limited between -10°~10°. The light irradiation part 200 is used for providing irradiation light along the second axis L2 and irradiating toward the wafer 400 (refer to FIG. 1 at the same time).

The image capturing unit 300 includes: a first support 310 , a second support 320 , a track 330 and a camera 340 movable on the track 330 . The first bracket 310 is erected on the stage 500 . The front end 321 of the second bracket 320 is pivotally connected to the base 311 of the first bracket 310 , and the second bracket 320 has a degree of freedom to rotate around the base 311 relative to the base 311 of the first bracket 310 . The extension arm 323 of the second bracket 320 is parallel to a horizontal plane formed by the first axis L1 and the second axis L2 (see FIG. 1 at the same time).

The track 330 is connected between the top seat 312 of the first support 310 and the rear end 322 of the second support 320 . Wherein, the top seat 312 of the first support 310 is pivotally connected to the track 330 , and the track 330 has a degree of freedom to rotate around the top seat 312 relative to the top seat 312 of the first support 310 . The track 330 provides the moving path of the camera 340, so that the angle relationship between the imaging direction of the camera 340 and the horizontal plane can be controlled. Track 330 may be configured as an arc track. The camera 340 can provide different imaging angles of the wafer 400 along the track 330 (the included angle θ ₃ as an example in FIG. 1 ). In addition, the track 330 can further be used to limit the movable range of the camera 340, so that the angle between an imaging axis of the camera 340 and the horizontal plane is limited to 15°~60°, which is helpful for capturing the distribution information on the surface of the metal sphere. The movement of the camera 340 on the track 330 can be controlled by electric drive or manual adjustment, and further, multiple cameras 340 can be arranged on the track 330 to achieve simultaneous multi-angle imaging.

Therefore, the extension arm 323 of the second bracket 320 of the imaging device can be based on the movable pivot connection between the front end 321 and the base 311 of the first bracket 310, and the movable pivot between the track 330 and the top seat 312 of the first bracket 310. connected, so that the second bracket 320 can rotate with the pivot joint of the front end 321 as the center of a circle, so that the extension arm 323 has a movable range (the range of the included angle θ ₂ as shown in FIG. 1 , between between 0°C and 50°C). Wherein, the front end 321 of the second bracket 320 can be disposed under the carrier 100 and the center of the circle is set on the central axis of the wafer 400 (parallel to the Z-axis and passing through the center of the wafer 400 ).

Based on the disposition that the image capturing position and the light emission position of the illuminating light are on the same side, the position of the extension arm 323 parallel to the first axis L1 (please refer to FIG. 1 ) can be defined as the boundary of the movable range. . The included angle between the extension arm 323 and the boundary is in the range of 0°-50° (the included angle θ ₂ in the example shown in FIG. 1 ), so that the image capturing position and the light emitting position of the illuminating light will be on the same side.

Further, the image capturing unit 300 may further include an indicating unit 350 , a first limiting unit 351 and a second limiting unit 352 disposed on the stage 500 . The first limiting unit 351 and the second limiting unit 352 (such as protrusions disposed on the platform 500 ) are used to limit the moving range of the extension arm 323 of the second bracket 320 . The indicating unit 350 (for example, a ruler configured on the stage 500) is configured to form an arc to indicate between the first limiting unit and the second limiting unit, and the indicating unit 350 is provided with a measuring scale to indicate the first limiting unit. The angle between the extension arm 323 of the second bracket 320 and the first axis L1. For example, when the movement of the second bracket 320 of the imaging device is manually adjusted or needs to be visually confirmed by the operator, the indicating unit 350 can play an indicating role to provide the angle between the extension arm 323 and the first axis L1 instructions.

Further, the carrier 100 may have a rotation axis (parallel to the Z-axis and passing through the center of the wafer 400), which is used to rotate the wafer 400 so that the fixed-position light irradiation unit 200 and the camera 340 In other words, different detection surfaces are provided for the illumination by the light irradiation unit 200 and the imaging by the camera 340 . On the other hand, the imaging angle can also be changed by controlling the angle between the extension arm 323 and the first axis L1 at the same time, and the movable second bracket 320 provides more control degrees of freedom for the detection device.

Next, please refer to FIGS. 3 and 4 . FIG. 3 is a schematic top view of an imaging device for inspecting the wafer surface in another embodiment of the present invention, and FIG. 4 is a schematic top view of another operation of the embodiment of FIG. 3 .

Under the condition that the carrier 100 does not rotate (wafer 400 does not rotate), the above-mentioned imaging device can be further configured with the second light irradiation part 200 ′ and the first support 310 having a rotational degree of freedom around the carrier 100 , to construct a 360-degree imaging environment of the wafer 400 . As shown in Figure 3, the track 330 and the second bracket 320 (covered by the track 330, refer to Figure ₂ ) on the stage 500, according to the foregoing, have a movable range (between the angle θ2 and the first axis L1 between 0 degrees and 50 degrees), the movable range is represented as one of the limited intervals in the example of FIG. 3 and FIG. 4 . The second light irradiation unit 200 ′ is disposed on the stage 500 and is used for providing irradiation light along the second axis L2 and irradiating toward the wafer 400 , the second light irradiation unit 200 ′ is opposite to the light irradiation unit 200 oriented configuration.

3 and 4, the center of the wafer 400 is taken as the center, the first axis L1 and the second axis L2 are two axes that construct a plane, and the first quadrant corresponds to FIG. 2 The movable range of the embodiment is represented as the first limited interval R1 in the example of FIG. 3 and FIG. 4 . The first limited interval R1 represents a movable range in which the second support 320 skims over the surface of the stage 500, as shown in Figures 1 and ₂ , the acute angle θ2 with the first axis L1 is also between 0 degrees and 50 degrees. between. Similarly, the second limited interval R2 in the second quadrant, the third limited interval R3 in the third quadrant, and the fourth limited interval R4 in the fourth quadrant, the limited intervals in each quadrant, such as 1 and 2, the acute angle θ ₂ with the first axis L1 is also between 0° and 50°.

Wherein, FIG. 4 shows the configuration state of the first bracket 310 in the example of FIG. 3 , based on the configuration of the degree of freedom of rotation around the center of the wafer 400 , compared to FIG. 3 after rotating 180 degrees. In each quadrant, the corresponding limited interval allows the image capturing unit 300 to complete image capturing at various angles, all of which are completed under the condition that the camera 340 and the light irradiation unit 200 are arranged on the same side. Under this configuration, when taking images of the first and second quadrants, the light irradiation unit 200 is used; and when taking images of the third and fourth quadrants, the second light irradiation unit 200' is used instead . In addition, the preferred mode of operation is to firstly capture images of the first and fourth quadrants (using the light irradiation part 200 and the second light irradiation part 200' in sequence), and then perform image captures of the second and third quadrants (according to Sequentially use the light irradiation part 200 and the second light irradiation part 200'), during this period, the first bracket 310 rotates once by 180 degrees, as shown in FIG. 3 and changes to the configuration state of FIG. 4 . During the imaging of the third quadrant and the fourth quadrant, since the irradiating light used comes from the second light irradiating part 200', the inclination angle _θ1 of the wafer 400 relative to the irradiating light needs to change its direction accordingly, so that the second The irradiation light provided by the second light irradiation unit 200 ′ can be irradiated on the wafer 400 obliquely.

Wherein, the configuration of the second light irradiation part 200' can be the same as that of the light irradiation part 200, including a light source unit and a diffusion unit. The diffusion unit is used to make the light emitted by the light source unit form parallel light (parallel to the second axis L2). The diffusion unit is, for example, a Fresnel lens.

To sum up the above, the imaging device and imaging equipment disclosed in the present invention for detecting the surface of a wafer can correctly obtain the image implanted on the wafer under the configuration that the imaging position and the light emitting position of the irradiating light are on the same side. The surface state of the metal ball improves the detection efficiency. In addition, the configuration and collocation of various mechanisms of the imaging device provide convenience and flexibility in imaging.

The present invention has been disclosed above with preferred embodiments, but those skilled in the art should understand that the embodiments are only used to describe the present invention, and should not be construed as limiting the scope of the present invention. It should be noted that all changes and replacements equivalent to this embodiment should be included in this within the scope of the invention. Therefore, the scope of protection of the present invention should be defined by the scope of the patent application.

100: bearing seat

200: Light irradiation department

210: Light source unit

220: Diffusion unit

340: camera

400: Wafer

L1: first axis

L2: second axis

I ₁ : image capture direction

I ₂ : Projection of I ₁ on the horizontal plane

θ ₁ : Inclination angle

θ ₂ : the angle between I ₂ and the first axis L1

θ ₃ : the angle between I ₁ and the horizontal plane

Claims (9)

An image-taking device for detecting the surface of a wafer, which is set on a stage and used for taking an image of a wafer implanted with a plurality of metal balls. circle, and based on a rotation range on the first axis, the wafer has an inclination angle compared to a horizontal plane; a light irradiation part is used to provide an irradiation along the second axis and toward the wafer light; and an image-taking part, comprising: a first support, a second support, a track and a video camera movable on the track, the first support is erected on the stage, and a front end of the second support is A base of the first bracket is pivotally connected and the extension arm of the second bracket is parallel to the horizontal plane. The track is connected between a top seat of the first bracket and a rear end of the second bracket. The bracket is centered on the front end so that the extension arm has a movable range across the surface of the stage, wherein the first axis is perpendicular to the second axis, and the extension arm of the second bracket is parallel to the The position of the first axis is defined as the boundary of the movable range, and the movable range is defined as a moving range between 0° and 50° from the boundary toward the direction of the light irradiation portion. The imaging device according to claim 1, wherein the orbit is an arc-shaped orbit, and the orbit is used to limit the included angle between an imaging axis of the camera and the horizontal plane within 15 degrees to 60 degrees. The imaging device according to claim 1, wherein the inclination angle is limited between -10° and 10°. The imaging device as described in claim 1, wherein the front end of the second support as the center of a circle is disposed below the carrier and located on the central axis of the wafer. The imaging device as described in any one of claims 1 to 4, wherein the imaging unit further includes an indicating unit, a first limiting unit and a second limiting unit arranged on the stage, the first limiting unit The position unit and the second limit unit are used to limit the movement range of the second bracket. The indicating unit is configured as an arc to indicate between the first limit unit and the second limit unit. A scale is provided to indicate the angle between the second bracket and the first axis. The imaging device according to claim 5, wherein the light irradiation part includes a light source unit and a diffusion unit, and the diffusion unit is a Fresnel lens. The imaging device according to claim 5, wherein the carrier has a rotation axis for rotating the wafer. The imaging device according to any one of claims 1 to 4, wherein the carrier has a rotation axis for rotating the wafer. An imaging device for detecting the surface of a wafer, comprising a second light irradiation unit and an imaging device as described in any one of Claims 1 to 6, the first bracket of the imaging unit of the imaging device There is a degree of freedom of rotation around the bearing base of the imaging device, the movable range of the second support of the imaging part of the imaging device includes a plurality of limited intervals, each of which covers the surface of the stage non-overlapping different surface areas, the second light irradiation part is arranged on the stage and is used to provide irradiation light along the second axis and toward the wafer, the second light irradiation part and the imaging device The light irradiation parts are arranged facing each other.

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