JP7624488B2 - Optical Inspection Systems - Google Patents

Description

The present disclosure relates to an optical inspection system, and more particularly to an optical inspection system disposed within a probing fixture for inspecting wafers.

During the wafer manufacturing process, there are usually corresponding inspection procedures within different manufacturing process steps, and the wafer needs to be transported to the inspection stage to perform certain inspection items to ensure the wafer yield.

However, conventional testing equipment often has limited internal space, meaning that the testing equipment faces challenges when it comes to expanding additional functions, whether that be adding equipment and/or improving testing accuracy.

In some embodiments of the present disclosure, the optical inspection system further provides an inspection procedure for foreign objects on the mounting device surface under dark field illumination in a probing inspection facility that uses a probe card.

In some embodiments of the present disclosure, the optical inspection system improves inspection accuracy under dark field illumination.

According to some embodiments, the optical inspection system of the probing equipment is disposed in a probing equipment for inspecting a wafer, and includes a movable mounting device for mounting a wafer in the probing equipment, and an optical positioning device for confirming the position of the wafer. The operation of the probing equipment includes a positioning stage, a probing stage, and a wafer exchange stage. The optical inspection system includes a rail assembly, a bridge base, a line scan imaging module, and a light source module. The rail assembly is horizontally bridged from the front end to the rear end in the probing equipment. The bridge base is movably mounted on the rail assembly so as to be controlled to move within a working area or to a waiting area in the probing equipment, and the bridge base is used to install the optical positioning device, is used to allow the optical positioning device to enter the working area in the positioning stage, and returns to the waiting area after the positioning stage is completed. The line scan imaging module is attached to the bridge base and defines a downward imaging plane, and when the mounting device is in the wafer exchange stage and waiting for a new wafer to be inspected, performs scanning imaging of the surface of the mounting device that is lifted to the imaging plane in the working area through the movement of the bridge base, thereby additionally operating a surface inspection procedure of the mounting device during the wafer exchange stage. The light source module is disposed in the probing equipment and is used to provide inspection light with an incident angle of more than 70 degrees to the imaging plane during the surface inspection procedure of the mounting device.

According to some embodiments, the mounting apparatus is used to mount wafers having a diameter of 12 inches or less, and the bridge base may be configured to span from the left side to the right side of the probing fixture. The projection of the bridge base on the imaging plane may define a centerline perpendicular to the direction of movement of the bridge base, and may tilt up from the imaging plane to an edge of the bridge base at the centerline, with a lift-up angle of 45 degrees or less.

According to this, in the probing equipment for inspecting wafers, an imaging plane is provided to the mounting device via a line scan imaging module attached to a bridge base, which allows the mounting device to be moved to a predetermined position more quickly during the wafer exchange stage, and further, dark field illumination is formed on the surface of the mounting device via a specific light source, so that the line scan imaging module is provided to perform scan imaging in the surface inspection procedure of the mounting device, and it is possible to know whether there is a foreign object on the surface of the mounting device. At this time, the operation of other devices in the probing equipment is not affected, and the overall time required for inspection of the probing equipment is not increased.

In addition, a function for detecting foreign objects on the surface of the mounting device can be added to the probing equipment, which can solve problems such as scratches and cracks on the wafers caused by foreign objects on the mounting device. If there is a foreign object on the mounting device that can damage the wafers, this situation will be detected immediately, and the subsequent warning and appropriate processing will improve the wafer yield.

FIG. 1 is a top view illustrating a schematic configuration of a probing facility according to a first embodiment. 2 is a side view showing a schematic diagram of the interior of a portion of the probing fixture of the embodiment of FIG. 1; FIG. 2 is a side view illustrating a schematic diagram of a line-scan imaging module according to an embodiment. FIG. 13 is a side view illustrating a line-scan imaging module according to another embodiment. 13 is a schematic side view of a line scan imaging module according to a further embodiment; FIG. 2 is a schematic side view of a line-scan imaging module and a light source module according to an embodiment; FIG. 13 is a schematic side view of a line-scan imaging module and a light source module according to another embodiment; FIG. 13 is a schematic side view of a line-scan imaging module and a light source module according to a further embodiment; FIG.

In order to fully understand the objectives, features, and advantages of the present invention, the present invention will be described in detail below in combination with specific examples and the accompanying drawings.

As used herein, the terms "a" or "one" are used to describe a unit, component, structure, device, module, system, portion, or area. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one, and the singular also includes the plural unless it is clear that it is meant differently.

As used herein, the terms "including," "comprising," "having," or any other variation thereof, are not necessarily limited to only those components, but may also include other components not expressly listed or inherent to such unit, member, structure, device, module, system, portion, or area.

Spatial terms (e.g., "above, on top, below, under," and similar terms) are used herein to facilitate the description of the relationship of one element or feature to another element or feature(s). Spatial terms are intended to include alternate orientations of each element or feature during use or operation in addition to the orientation depicted in the drawings. These elements or features may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), in which case the spatial terms used herein should be interpreted accordingly.

As used herein, these space-related terms include the placement or non-placement of other element(s) or feature(s) between these elements or features. For example, when a description refers to a first member being formed on or above a second member, it can include embodiments in which the first and second members are in direct contact, or embodiments in which an additional member is formed between the first and second members such that the first and second members are not in direct contact with each other.

As used herein, the terms "approximately", "approximately", "about", "approximately", "substantially" or "essentially" generally mean "any approximation of a given numerical value" or "any approximation of a given range". These approximations vary depending on the relevant technical field, and the range of variation should correspond to the broadest interpretation understood by those skilled in the art to cover similar implementations and all modifications based on such variations. In some embodiments, they should generally mean within 20 percent, even within 10 percent, or even within 5 percent of the "given numerical value" or "given range". Numerical values given in this specification are approximate values, and unless otherwise expressly indicated, it is meant that these numerical values can be estimated to fall within the range of "approximately", "approximately", "about", "approximately", "substantially" or "essentially" or include other approximations.

The diagrams in the drawings are simplified to emphasize the explanation of the configuration and operation of the optical inspection system within the probing facility.

Referring to FIG. 1 and FIG. 2, FIG. 1 is a top view showing a schematic diagram of a probing equipment according to a first embodiment, and FIG. 2 is a side view showing a schematic diagram of a part of the inside of the probing equipment according to the embodiment of FIG. 1. The probing equipment performs testing on a wafer by attaching a probe card 310 to a mounting port 300 on a housing above the equipment and having the probe card 310 face downward into the inside of the probing equipment. Specifically, the probe card 310 uses probes 311 protruding downward, and when the wafer is raised to a testing height by the mounting device 200 and the transport device 210, the probes 311 come into contact with contact pads on the wafer, thereby performing a related electrical characteristic test.

The operation of the probing equipment includes a positioning phase, a probing phase, and a wafer exchange phase, the control of which is determined and operated by the controller. The positioning phase precisely aligns the contact pads on the wafer to be inspected with the corresponding probes 311 on the probe card 310 so that when the wafer to be inspected is lifted to the inspection height via the mounting device 200 and the transport device 210 in the subsequent probing phase, the probes 311 can be electrically connected to the corresponding contact pads on the wafer to be inspected. In the positioning phase, to determine whether the correct position has been reached, the imaging device 121 and the illumination device 122 of the optical positioning device provided on the bridge base 120 work together to image the mounting device 200 on which the wafer is mounted and the wafer.

During the wafer exchange stage, the transport device 210, which can move freely in each direction (X, Y, Z), lowers the placement device 200 to a low position and allows it to enter an exchange area in the probing equipment, allowing a wafer pick-and-place device outside the probing equipment to exchange the wafer. For example, the wafer pick-and-place device picks up a wafer that has already been inspected from the placement device 200 and transfers it into a wafer box, and picks up an uninspected wafer from the wafer box and transfers it onto the placement device 200.

During the operation of the probing equipment, the wafer may be frequently picked up from or placed on the placement device 200. Since the surface of the placement device is in close contact with the wafer, if there is a foreign object on the wafer surface, the pressing force of the probe 311 during the probing stage may easily cause problems such as scratches and cracks on the wafer. In this embodiment, the line scan imaging module 130 and the light source module 140 are further configured to additionally perform a surface inspection procedure of the placement device during the wafer exchange stage.

The rail assembly 110 in the probing equipment is horizontally spanned from the front end F to the rear end B in the probing equipment. The bridge base 120 is movably mounted on the rail assembly 110 and can move between the front end F and the rear end B in the probing equipment under the control of the controller. Specifically, in the surface inspection procedure of the mounting device which requires the operation of the line scan imaging module 130, or in the positioning stage which requires the operation of the imaging device 121 and the lighting device 122, the bridge base 120 moves away from the waiting area S2 and operates in the working area S1. As the bridge base 120 moves along the rail assembly 110 in the working area S1, the imaging device 121 and the lighting device 122 complete the confirmation of the position information in the positioning stage, and the conveying device 210 is controlled by the controller to fine-tune the mounting device 200 based on the position information, and the positioning stage is completed and terminated after the bridge base 120 returns to the waiting area S2.

During the probing stage, the wafer is lifted and the probe 311 is brought into contact with the wafer, establishing an electrical connection path for carrying out various electrical property tests. Then, the wafer is replaced with the next wafer to be inspected. During the wafer replacement stage, the inspected wafer is picked up, so the top surface of the mounting device 200 is empty, and the next wafer to be inspected is immediately transported and placed on the mounting device 200. During a short period when no wafer is placed on the surface of the mounting device 200 and waiting for the next wafer to be inspected, the present embodiment further controls, through the control of the controller, the bridge base 120, which is originally only in the waiting area S2 at this stage, to enter the working area S1, and the transport device 210 lifts the mounting device 200 to the imaging plane P1, and the bridge base 120 translates in the direction X to move above the mounting device 200, and when the surface of the mounting device 200 reaches the imaging plane P1, the surface inspection procedure of the mounting device can be operated. The imaging plane P1 is used by the line scan imaging module 130 to acquire images required for the surface inspection procedure of the mounting device.

Specifically, the light source module 140 provides the inspection light I with an incident angle θ1 exceeding 70 degrees to the imaging plane P1 to the surface of the mounting device 200, and the line scan imaging module 130 translates slowly above the mounting device 200 through the bridge base 120, or the conveying device 210 translates the mounting device 200 slowly relative to the line scan imaging module 130 to realize line scan imaging. Through the line scan imaging module 130 above the mounting device 200 and the inspection light I with an incident angle θ1 exceeding 70 degrees, imaging under dark field illumination is constructed. If there is a foreign object on the surface of the mounting device 200, light is reflected to the line scan imaging module 130 based on the irregular characteristics of the surface, and the imaging screen of the line scan imaging module 130 shows bright spot information, and the bright spot is the location of the foreign object. In contrast, if there is no foreign object on the surface of the mounting device 200, the imaging screen shows dark information, the surface of the mounting device 200 reflects the inspection light I at a low angle, and the light cannot enter the line scan imaging module 130.

Through the line scan imaging module 130 mounted on the bridge base 120, a quick match (the moving direction X of the bridge base 120 matches the moving direction Y of the transport device 210) can be formed with the transport device 210 during the wafer exchange phase in two axial directions, so that the surface inspection procedure of the loading device can be completed within a short time and does not affect the operation of other devices in the probing equipment. This allows scanning imaging to be performed within a time range of 5 seconds during the surface inspection procedure of the loading device. After the surface of the loading device 200 is inspected, the transport device 210 is lowered to a height for receiving the next wafer, and the controller continues to operate in the wafer exchange phase, and after obtaining a new inspected wafer, continues the positioning phase and the probing phase to complete the inspection of each wafer.

In other embodiments, the controller may be configured to perform a surface inspection procedure of the mounting device on the surface of the mounting device 200 after all wafers in one wafer box (Front Opening Unified Pod, FOUP) have been subjected to the probing stage. Therefore, whether the surface inspection procedure of the mounting device is performed every time a wafer is replaced or every time a wafer box is replaced (after probing multiple wafers) is a variation according to various embodiments and can be applied to each embodiment. The controller is a control center for controlling the operation and cooperation of each device in the probing equipment, and is described with various functional operations in each embodiment, but the controller is omitted from the drawings to simplify the drawings.

Referring now to FIG. 1 and FIG. 3 at the same time, FIG. 3 is a schematic side view of a line scan imaging module according to an embodiment. When viewed from the top view of FIG. 1, the bridge base 120 has a substantially rectangular shape, so that it can form a corresponding projection area on the imaging plane P1, and as shown in FIG. 1 and FIG. 3, this projection area can define a center line CL perpendicular to the moving direction X of the bridge base 120. The bridge base 120 spans from the left side L to the right side R within the probing equipment.

In order to further improve the accuracy of the surface inspection procedure of the mounting device due to the limited internal space of the probing equipment and the short time of the wafer exchange stage, for the wafer to be inspected with a diameter of 12 inches or less, the imaging plane P1 of the line scan type line scan imaging module 130 can be further specified by the following condition. That is, tilt up from the P1 surface of the imaging plane at the position of the center line CL, tilt up to the edge of the bridge base 120, and then stop to form a lift-up angle θ2, and this lift-up angle θ2 is 45 degrees or less. Through this specific condition, the working distance of the line scan camera of the line scan imaging module 130 and the relative mounting position of the light source module 140 (to provide the imaging plane P1 with an inspection light I with an incident angle of more than 70 degrees) are adjusted to realize a matching configuration, and a good detection effect is achieved for the presence or absence of foreign matter on the surface of the mounting device. In particular, when using a mounting device 200 with a groove on its surface, the surface inspection procedure of the mounting device requires a configuration condition with a better detection effect.

As shown in FIG. 3, the working distance of the line scan imaging module 130 (i.e., the working distance of the line scan camera) is about 4.8 (mm), i.e., the distance D1 between the imaging plane P1 and the line scan imaging module 130 corresponds to this working distance. Note that the line scan imaging module 130 is configured to have a thickness D2 of 27 (mm) or less, and the top and bottom surfaces of the line scan imaging module 130 have a height that satisfies this condition so as not to exceed the top and bottom surfaces of the bridge base 120.

On the other hand, referring to FIG. 2 together, the light source module 140 is disposed inside the housing at the front end F or rear end B of the probing equipment (FIG. 2 shows that it is disposed inside the housing at the front end F). Further combined with the example of FIG. 3, compared with the bridge base 120, when the light source module 140 is located on the same side as the line scan imaging module 130, the inspection light I is irradiated from the right side as shown in FIG. 3.

Referring now to FIG. 4, a side view is shown that shows a schematic diagram of a line-scan imaging module according to another embodiment. Compared to FIG. 3, the light source module 140 is disposed on the other side of both sides of the bridge base 120. In contrast, when the light source module 140 shown in FIG. 2 is located on the same side as the line-scan imaging module 130 shown in FIG. 4, the inspection light I is irradiated from the left side as shown in FIG. 4.

Referring now to FIG. 5, a side view is shown that illustrates a schematic diagram of a line-scan imaging module according to a further embodiment. The line-scan imaging module 130 is disposed within a slit in the bridge base 120 and is located at the center of the bridge base 120. In the example of FIG. 5, the line-scan imaging module 130 has a thickness of about 26-27 mm, so that it can be disposed between the bridge bases 120.

Referring now to Figures 6 to 8, Figure 6 is a schematic side view of a line scan imaging module and a light source module according to one embodiment, Figure 7 is a schematic side view of a line scan imaging module and a light source module according to another embodiment, and Figure 8 is a schematic side view of a line scan imaging module and a light source module according to a further embodiment.

In the examples of Figures 6 to 8, the light source module 140 is disposed on one of the two sides of the bridge base 120 via a bracket 141. The line scan imaging module 130 can also be disposed on one of the two sides of the bridge base 120 or within the bridge base 120 slit. In the example of Figure 6, the light source module 140 and the line scan imaging module 130 are each located on the same side of the bridge base 120, whereas in the example of Figure 7, the light source module 140 and the line scan imaging module 130 are each located on opposite sides of the bridge base 120.

In short, through a line scan imaging module mounted on a bridge base in the probing equipment, the loading device is provided with an imaging plane that can be lifted into a predetermined position during the wafer exchange stage, and further through a specific light source, dark field illumination is formed on the surface of the loading device to perform a surface inspection procedure for the loading device, thereby adding a foreign object detection function on the surface of the loading device without affecting the operation of other devices in the probing equipment, thereby further improving the wafer yield.

The present invention has been disclosed in the above best embodiment, but as will be understood by those skilled in the art, this embodiment is merely used to explain the present invention and should not be understood to limit the scope of the present invention. It should be noted that all modifications and replacements that have the same effect as this embodiment are included within the scope of the present invention. Therefore, the scope of protection of the present invention is defined in accordance with the scope of the claims.

110 Rail assembly 120 Bridge base 121 Imaging device 122 Illumination device 130 Line scan imaging module 140 Light source module 141 Bracket 200 Mounting device 210 Transport device 300 Mounting port 310 Probe card 311 Probe θ1 Incident angle θ2 Lift-up angle B Rear end CL Center line D1 Spacing distance D2 Thickness F Front end I Inspection light L Left side P1 Imaging plane R Right side S1 Working area S2 Waiting area X direction Y direction Z direction

Claims (10)

An optical inspection system for a probing facility, the optical inspection system being disposed in a probing facility for inspecting a wafer, the optical inspection system including a movable mounting device for mounting a wafer in the probing facility, and an optical positioning device for confirming a position of the wafer, the operation of the probing facility including a positioning step, a probing step, and a wafer exchange step, the optical inspection system comprising:
a rail assembly horizontally extending from a front end to a rear end within the probing equipment;
a bridge base that is movably mounted on the rail assembly so as to be controlled to move within a working area or to a waiting area within the probing equipment, the bridge base being used for installing the optical positioning device, and being used to allow the optical positioning device to enter the working area during the positioning step, and returning to the waiting area after the positioning step is completed;
a line scan imaging module attached to the bridge base, defining a downward imaging plane, and performing a scanning type imaging of a surface of the mounting device lifted up to the imaging plane in the working area through the movement of the bridge base when the mounting device is in the wafer exchange stage and waiting for a new wafer to be inspected, thereby additionally operating a surface inspection procedure of the mounting device during the wafer exchange stage;
a light source module arranged inside a housing of the probing equipment or on the bridge base, for providing inspection light having an incident angle of more than 70 degrees on the imaging plane during a surface inspection procedure of the mounting device. The optical inspection system of claim 1, wherein the mounting device is used to mount a wafer having a diameter of 12 inches or less, the bridge base spans from the left side to the right side within the probing equipment, the projection of the bridge base on the imaging plane defines a centerline perpendicular to the direction of movement of the bridge base, and tilts up from the imaging plane to the edge of the bridge base at the centerline, with a lift-up angle of 45 degrees or less. the line scan imaging module is disposed within a slit of the bridge base or on one of both sides of the bridge base, and configured to perform scanning imaging for a time range of 5 seconds or less during a surface inspection procedure of the mounting apparatus ;
Each side of the bridge base includes a first side edge and an opposite second side edge, the first side edge facing a front end of the probing fixture and the second side edge facing a rear end of the probing fixture;
The optical inspection system of claim 2 , wherein the slit in the bridge base is located at a center of the rectangular bridge base in a side view and is configured to accommodate the line-scan imaging module . The optical inspection system of claim 3, wherein the working distance of the line scan imaging module is configured to be 4.8 (mm), and the distance between the imaging plane and the line scan imaging module corresponds to the working distance. The optical inspection system of claim 4, wherein the line scan imaging module has a thickness of 27 mm or less and a height that does not exceed the top and bottom surfaces of the bridge base. The optical inspection system according to any one of claims 3 to 5, wherein the light source module is disposed inside a housing at the front or rear end of the probing equipment. The optical inspection system of claim 6, wherein the line scan imaging module is disposed on one of both sides of the bridge base, and the light source module is located on the same side as the line scan imaging module compared to the bridge base. The optical inspection system according to any one of claims 3 to 5, wherein the light source module is disposed on one of both sides of the bridge base. The optical inspection system of claim 8, wherein the line scan imaging module is disposed on one of both sides of the bridge base, and the light source module and the line scan imaging module are each located on the opposite side of the bridge base. The optical inspection system of claim 8, wherein the line scan imaging module is disposed on one of the two sides of the bridge base, the light source module and the line scan imaging module are located on the same side of the bridge base, and the line scan imaging module is located between the bridge base and the light source module.