JP7007993B2 - Dicing tip inspection device - Google Patents

Description

The present invention relates to a dicing chip inspection device that inspects a device region and a peripheral region of a device chip that is placed on a wafer on which a scribe line is formed or diced.

A dicing device is known as a device for cutting or scribing a work such as a wafer on which a semiconductor device or an electronic component is formed (for example, Patent Documents 1 and 2).

Further, a technique has been proposed in which an abnormality such as a processing size or a processing state is detected by imaging a work during dicing processing, and a countermeasure is taken according to the abnormality state (for example, Patent Document 2).

In addition, a technique for inspecting the effective region (that is, the device region) and the edge (that is, the peripheral region) of the device chip by imaging the device chips arranged on the wafer on which the scribe line is formed or diced one by one (that is, the peripheral region). That is, inspection by an inspection device) has been proposed (for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 62-53804 Japanese Unexamined Patent Publication No. 2009-253071 Japanese Unexamined Patent Publication No. 2017-161236

In the technique disclosed in Patent Document 2, when trying to detect fine cracks and the like, the moving speed of the wafer (that is, the cutting speed) is increased to the extent that the inspection quality is not affected while increasing the imaging magnification. ) Was needed to be suppressed.

On the other hand, there is a need to increase the number of wafers processed per unit time (so-called WPH) as much as possible, and inspection during dicing checks the position of the machined groove (calf), calf width, presence of large chipping (chips), etc. Only the measurement was performed, and the detection of minute cracks was left to a dedicated machine (that is, an inspection device).

However, in the inspection by the inspection device, both the device area of the device chip and the chip end portion (that is, the peripheral area) in which the dicing line (including the scribe line; the same applies hereinafter) are formed are provided with a predetermined accuracy within a predetermined time. There is a need to inspect, but if all the divided areas were inspected at the same high magnification, the inspection time required for one wafer would be long. On the other hand, there is a rule that if all the divided regions are inspected at the same low magnification with the intention of shortening the inspection time, defects such as fine cracks lurking in the dicing line cannot be reliably detected. Therefore, there has been a demand for an inspection device capable of inspecting both the device area and the peripheral area with a predetermined accuracy within a predetermined time.

Therefore, the present invention has been made in view of the above problems, and the device chip can be used while reliably detecting defects such as cracks, chipping, and film peeling lurking in the dicing line of the wafer on which the scribe line is formed or diced. It is an object of the present invention to provide a dicing chip inspection apparatus capable of shortening the time for inspecting a device area.

In order to solve the above problems, one aspect of the present invention is
In a dicing chip inspection device that inspects the device area and the peripheral area of the device chip placed on the diced wafer.
The wafer holding part that holds the wafer and the wafer holding part,
An imaging unit that captures a predetermined area set on the wafer at a predetermined imaging magnification, and an imaging unit.
A relative moving part that moves the wafer and the image pickup part relative to each other,
An inspection recipe registration unit that registers the direction and speed of relative movement in the relative movement unit, as well as the imaging magnification and imaging position in the imaging unit as inspection recipes.
It is equipped with a control unit that controls the imaging unit and the relative movement unit based on the inspection recipe.
The control unit
A peripheral area inspection mode in which an image is taken along the dicing line so that the dicing line of the wafer diced at a predetermined image magnification is included, and the peripheral area of the device chip is inspected.
It is equipped with a device area inspection mode that inspects the device area by performing imaging so as to skip the dicing line at an imaging magnification lower than the imaging magnification in the peripheral area inspection mode.
The inspection recipe registration unit is characterized in that an inspection recipe for executing at least one of the device area inspection mode and the peripheral area inspection mode is registered.

According to the above-mentioned dicing chip inspection device, the region along the dicing line (peripheral region) can be imaged with a high-magnification field size in the peripheral region inspection mode, and defects such as cracks and chipping can be reliably detected. .. On the other hand, in the device area inspection mode, the device area of the device chip can be imaged with a relatively low magnification field size to shorten the inspection time.

It is a schematic diagram which shows the whole structure of the example of the form which embodies the present invention. It is a perspective view which shows the main part of the example of the form which embodies the present invention. It is a conceptual diagram in an example of the form which embodies the present invention. It is a conceptual diagram in an example of the form which embodies the present invention. It is a flow figure in an example of the form which embodies the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

In the following description, the three axes of the Cartesian coordinate system are expressed as X, Y, and Z, the horizontal direction is expressed as the X direction and the Y direction, and the direction perpendicular to the XY plane (that is, the gravity direction) is expressed as the Z direction. do. Further, in the Z direction, the direction against gravity is expressed as the upper direction, and the direction in which gravity acts is expressed as the lower direction. Further, the direction of rotation with the Z direction as the central axis is defined as the θ direction.

FIG. 1 is a schematic view showing an overall configuration of an example of a form embodying the present invention. FIG. 1 shows a schematic view of the dicing chip inspection device 1 according to the present invention.

The dicing chip inspection device 1 inspects the device region Rc and the peripheral region Re of the device chip C arranged in the diced wafer W. The device region Rc is a region in which the main circuit of the device chip C is patterned. On the other hand, the peripheral region Re is an region arranged around the device region Rc of the device chip C (also referred to as the outer side), and is a region set to allow the misalignment of the dicing line DL (margin region). , Also called cutting).

The peripheral region Re of the device chip C is adjacent to the dicing line DL. The dicing line DL is a machined groove generated when the wafer W is scribed or cut, and is actually a space between the ridges of the processed wafer W. In the present application, for convenience of explanation, the ridgeline of the processed wafer W is referred to as a dicing line DL.

Specifically, the dicing chip inspection device 1 includes a wafer holding unit 2, an imaging unit 3, a relative moving unit 4, an inspection recipe registration unit 5, a control unit 9, a computer CN, and the like.

The wafer holding unit 2 holds the wafer W. For example, the diced wafer W is held on the lower surface side by using a wafer ring R (also referred to as a flat ring or a dicing ring) and an expand sheet (not shown). Specifically, the wafer holding portion 2 maintains a horizontal state while supporting the wafer W from the lower surface side via a wafer ring R or the like. More specifically, the wafer holding portion 2 includes a wafer mounting table 20 having a horizontal upper surface.

The wafer mounting table 20 is provided with a groove or a hole in a portion in contact with the wafer ring or the like holding the wafer W, and the groove or the hole has a negative pressure of a vacuum pump or the like via a switching valve or the like. It is connected to the generating means. Then, the wafer holding portion 2 can hold and release the wafer ring and the like by switching these grooves and holes to a negative pressure state or an atmospheric release state.

The image pickup unit 3 captures a predetermined area set in the wafer W at a predetermined imaging magnification. Specifically, the imaging unit 3 captures the device region Rc to be inspected and the peripheral region Re, and has a configuration in which the imaging magnification is switched so that the imaging can be performed at an imaging magnification suitable for these regions. is doing. More specifically, the image pickup unit 3 includes a lens barrel 30, an illumination unit 31, a half mirror 32, a plurality of objective lenses 33a and 33b, a revolver mechanism 34, an image pickup camera 35, and the like.

The lens barrel 30 fixes the illumination unit 31, the half mirror 32, the objective lenses 33a and 33b, the revolver mechanism 34, the image pickup camera 35, and the like in a predetermined posture, and guides the illumination light and the observation light. The lens barrel 30 is attached to the device frame 1f via a connecting metal fitting or the like (not shown).

The illumination unit 31 emits the illumination light L1 necessary for imaging. Specifically, the lighting unit 31 may be exemplified by a laser diode, a metal halide lamp, a xenon lamp, LED lighting, or the like.

The half mirror 32 reflects the illumination light L1 emitted from the illumination unit 31 and irradiates the wafer W side, and passes the light (reflected light, scattered light) L2 incident from the wafer W side to the image pickup camera 35 side. Is.

The objective lenses 33a and 33b form an image of the image pickup area on the work W on the image pickup camera 35 at different predetermined observation magnifications.
The revolver mechanism 34 switches which of the objective lenses 33a and 33b is used. Specifically, the revolver mechanism 34 rotates and stands still by a predetermined angle based on manual or external signal control.

The image pickup camera 35 captures an image pickup area F on the work W and acquires an image. The acquired image is output as a video signal or video data to the outside (in the present invention, a chip position calculation unit whose details will be described later).

The relative moving unit 4 relatively moves the wafer holding unit 2 and the imaging unit 3.
Specifically, the relative moving portion 4 includes an X-axis slider 41, a Y-axis slider 42, and a rotation mechanism 43.

The X-axis slider 41 is mounted on the device frame 1f, and the Y-axis slider 42 is moved in the X direction at an arbitrary speed and stopped at an arbitrary position. Specifically, the X-axis slider is composed of a pair of rails extending in the X direction, a slider unit that moves on the rails, and a slider drive unit that moves and stops the slider unit. The slider drive unit can be configured by a servomotor that rotates and stands still by signal control from the control unit CN, a combination of a pulse motor and a ball screw mechanism, a linear motor mechanism, and the like. Further, the X-axis slider 41 is provided with an encoder for detecting the current position and the amount of movement of the slider portion. Examples of this encoder include a linear scale called a linear scale in which fine irregularities are carved at a predetermined pitch, a rotary encoder that detects the rotation angle of a motor that rotates a ball screw, and the like.

The Y-axis slider 42 moves the rotation mechanism 43 in the Y direction at an arbitrary speed based on the control signal output from the control unit CN, and makes it stand still at an arbitrary position. Specifically, the Y-axis slider is composed of a pair of rails extending in the Y direction, a slider unit that moves on the rails, and a slider drive unit that moves and stops the slider unit. The slider drive unit can be configured by a servomotor that rotates and stands still by signal control from the control unit CN, a combination of a pulse motor and a ball screw mechanism, a linear motor mechanism, and the like. Further, the Y-axis slider 42 is provided with an encoder for detecting the current position and the amount of movement of the slider portion. Examples of this encoder include a linear scale called a linear scale in which fine irregularities are carved at a predetermined pitch, a rotary encoder that detects the rotation angle of a motor that rotates a ball screw, and the like.

The rotation mechanism 43 rotates the wafer mounting table 20 at an arbitrary speed in the θ direction and makes it stand still at an arbitrary angle. Specifically, the rotation mechanism 43 can be exemplified as a rotation / stationary mechanism such as a direct drive motor that is rotated / stationary at an arbitrary angle by signal control from an external device. The wafer mounting table 20 of the wafer holding portion 2 is mounted on the member on the rotating side of the rotating mechanism 43.

Since the relative moving unit 4 has such a configuration, the wafer W is made independent of the imaging unit 3 in the XYθ direction while holding the wafer W to be inspected, or in combination with each other. It can be moved relative to each other at a speed or angle, or it can be stationary at any position or angle.

FIG. 2 is a perspective view showing a main part of an example of a form embodying the present invention. FIG. 2 shows a state in which the wafer W and the imaging unit 3 are relatively moved along the dicing line DL, and the peripheral region Re of the device chip C is sequentially imaged while the imaging area F is moved in the direction indicated by the arrow Vs. ing.

The inspection recipe registration unit 5 registers the direction and speed of the relative movement in the relative movement unit 4, the imaging magnification, the imaging position, and the like in the imaging unit 3 as inspection recipes. Then, the inspection recipe registration unit 5 can register inspection recipes related to the device area inspection mode and the peripheral area inspection mode, which will be described in detail later, and the inspection recipes for executing both or at least one of these modes are registered. ing. Specifically, the inspection recipe registration unit 5 images which location of the wafer W at what imaging magnification and in what order (that is, imaging route T) in each of the device region inspection mode and the peripheral region inspection mode. Or, information (also called recipe information) such as the movement speed and the imaging interval at that time and the movement pitch and the feed speed can be registered as an inspection recipe for each inspection type.

The control unit 9 has the following functions and roles, for example.
-Outputs a signal for holding / releasing the waha W to the waha holding unit 2.-Controls the revolver mechanism 34 to switch the objective lens (imaging magnification) to be used.-Outputs an imaging trigger to the imaging camera 35.・ Drive control of the relative moving unit 4: A function to output a drive signal while monitoring the current positions of the X-axis slider 41, the Y-axis slider 42, and the rotation mechanism 43. ・ The image pickup position, the image pickup route T, and the image pickup interval (pitch). , Interval) registration ・ Registration of inspection recipes, switching of inspection recipes to be used ・ Inspection based on captured images

More specifically, the control unit 9 includes a computer CN, a programmable logic controller, etc. (that is, hardware), and an execution program thereof (that is, software). Further, the inspection recipe registration unit 5 is composed of a part of a storage unit (register, memory, HDD, SSD, etc.) of the computer CN.

Further, the control unit 9 controls the image pickup unit 3 and the relative moving unit 4 based on the inspection recipe, and means for setting a peripheral area inspection mode and an operation mode called a device area inspection mode (for example, a setting screen or the like). ) And execution means (computer CN and control equipment, etc.).

FIG. 3 is a conceptual diagram in an example of a form embodying the present invention. FIG. 3 illustrates an imaging route T and an imaging region F in the peripheral region inspection mode.

In the peripheral area inspection mode, an image is taken along the dicing line DL so that the dicing line DL of the wafer W diced at a predetermined image magnification (relatively high magnification) is included, and the peripheral area of the device chip C is taken. This is the operation mode for inspecting Re.

Specifically, in the peripheral region inspection mode, as shown in FIG. 3A, imaging is performed by the imaging route T in which the imaging region F is relatively moved along the dicing line DL extending in the X direction, and then the image is taken. As shown in 3 (b), cracks lurking in the dicing line DL over the entire surface of the wafer W while performing imaging by the imaging route T in which the imaging region F is relatively moved along the dicing line DL extending in the Y direction. The peripheral region Re is inspected at a predetermined imaging magnification (relatively high magnification) such that defects such as chipping can be reliably detected.

More specifically, in the peripheral area inspection mode, edge extraction processing is performed to detect the chip end portion (that is, the ridge line) of the device chip C, and a part of the ridge line does not enter the preset intrusion prohibition area. It is inspected whether or not cracks or chipping extending from the ridgeline have entered the intrusion prohibited area.

In the embodiment shown in FIG. 3, the imaging magnification and the imaging region F are set so that the peripheral regions Re of a plurality of device chips arranged adjacent to each other are simultaneously imaged in a positional relationship such as straddling the dicing line DL. The imaging route T or the like is set in the inspection recipe registration unit 5.

FIG. 4 is a conceptual diagram in an example of a form embodying the present invention. FIG. 4 illustrates an imaging route T and an imaging region F in the device region inspection mode.

The device area inspection mode is an imaging magnification lower than the imaging magnification in the peripheral region inspection mode, and imaging is performed by an imaging route T in which the imaging region F is relatively moved so as to skip the dicing line DL of the diced wafer W. This is an operation mode for inspecting the device region Rc of the device chip C over the entire surface of the wafer W.

Specifically, in the device area inspection mode, a predetermined magnification that can determine whether there is any foreign matter or scratches on the device area Rc, whether there is a clear pattern collapse or a film formation defect, etc. ( Imaging / inspection of the device region Rc is performed at a relatively low magnification).

More specifically, in the device area inspection mode, an image (so-called teaching image) in a state in which foreign matter, scratches, pattern collapse, film formation failure, etc. are not generated is registered in advance in the device area Rc, and the teaching is performed. The image is compared with the image of the device region Rc imaged for inspection from now on, and it is inspected whether the device region Rc is free from foreign matter, scratches, pattern collapse, film formation failure, and the like.

In the embodiment shown in FIG. 4, the imaging magnification, the imaging region F, the imaging route T, and the like are set so that the predetermined region imaged in the device region inspection mode skips the predetermined region imaged in the peripheral region inspection mode. It is set in the inspection recipe registration unit 5.

FIG. 5 is a flow chart in an example of a form embodying the present invention. FIG. 5 shows a configuration in which the device region Rc and the peripheral region Re of the device chip C arranged in the wafer W are imaged and inspected using the dicing chip inspection device 1 step by step as a series of flows. ..

First, the inspection recipe is set (step s11), and the inspection mode and order of the wafer W are determined. Next, the wafer W is placed on the wafer mounting table 20 of the dicing chip inspection device 1 (step s12), moved to a reading position of a reference mark (not shown) formed on the wafer W, and alignment is performed (step s12). Step s13).

Subsequently, based on the inspection recipe, the mode is switched to the peripheral region inspection mode (step s21), and the revolver mechanism 34 is rotated so that a high-magnification lens is selected (step s22). Then, imaging / inspection is performed while the imaging unit 3 and the relative moving unit 4 are relatively moved (step s23). It is determined whether or not all the imaging in this mode is completed (step 24), and if not, the imaging / inspection is continued. If the imaging is completed, it is determined whether to execute another inspection mode (step s25).

Then, if another inspection mode (that is, device area inspection mode) is to be executed, the device area inspection mode is switched to (step s31), and the revolver mechanism 34 is rotated so that a low-magnification lens is selected (step). s32). Then, imaging / inspection is performed while the imaging unit 3 and the relative moving unit 4 are relatively moved (step s33). It is determined whether or not all the imaging in this mode is completed (step 34), and if not, the imaging / inspection is continued. If the imaging is completed, the wafer W is discharged to the outside of the device (step s41). Even when the other inspection modes are not executed in step 25, the wafer W is discharged to the outside of the device (step s41).

Then, it is determined whether or not to perform the imaging / inspection of the next wafer W (step s42), and when the imaging / inspection is performed, the above-mentioned steps s12 to s41 are repeated. On the other hand, if the imaging / inspection is not performed, the inspection is terminated.

In the above description, the procedure of first executing the peripheral area inspection mode and then executing the device area inspection mode has been exemplified. However, in embodying the present invention, the order of these inspection modes may be reversed. Further, these inspection modes indicate a series of operation flows and states, and are not limited to the case where they are registered in the state specified in the inspection recipe, and different imaging magnifications, imaging routes T, etc. are registered without being specified. Including the case where it is done.

The output of the image pickup trigger from the control unit 9 to the image pickup unit 3 can be exemplified by the following method.
-A method in which the illumination light L1 is emitted for a very short time (so-called strobe emission) every time the illumination light is moved by a predetermined distance while the scan is relatively moved in the X direction or the Y direction.
-Alternatively, a method of moving and stationary relative to a predetermined position and irradiating the illumination light L1 in a stationary state to take an image (so-called step & repeat).

Further, the image pickup trigger means an image capture instruction to the image pickup camera 35 and an image processing device (not shown), a light emission instruction of the illumination light L1 and the like. Specifically, as an image pickup trigger, the illumination light L1 is made to emit strobe light or (case 2) the illumination light L1 is irradiated during the time during which the image pickup camera 35 can take an image (so-called exposure time). During the time you are in the picture, you can take an image. Alternatively, the image pickup trigger is not limited to the instruction to the image pickup camera 35, but may be an image capture instruction to the image processing device that acquires the image (Case 3). By doing so, it is possible to cope with a form in which a video signal or video data is sequentially output from the image pickup camera 35.

Since the dicing chip inspection device 1 according to the present invention has such a configuration, the region along the dicing line (that is, the peripheral region Re) is imaged with a high-magnification visual field size in the peripheral region inspection mode. Defects such as cracks and chipping can be reliably detected (that is, inspected). On the other hand, in the device area inspection mode, the device area Rc of the device chip C can be imaged with a field size of a relatively low magnification to shorten the inspection time. That is, the dicing chip inspection device 1 can inspect both the device region Rc and the peripheral region Re within a predetermined time with a predetermined accuracy.

[Another form]
In the above description, the imaging magnification, the imaging region F, the imaging route T, etc. are set so that the peripheral regions Rc of the plurality of device chips C arranged adjacent to each other are simultaneously imaged in a positional relationship such as straddling the dicing line DL. The configuration set in the inspection recipe registration unit 5 is illustrated.

Such a configuration is preferable because the number of imagings can be reduced and the inspection time spent per wafer W can be shortened.

However, when the width of the dicing line DL is wider than that of the imaging region F and the ridgeline of the peripheral region Re tends to deviate from the field of view, or the cracks or chips to be detected are small, the dicing line DL may be straddled when the imaging magnification is increased. If it is not possible to image at the same time due to the positional relationship, the peripheral region Rc of one device chip C may be imaged.

1 Dicing chip inspection device 2 Wafer holding unit 3 Imaging unit 4 Relative moving unit 5 Inspection recipe registration unit 9 Control unit 1f Device frame 20 Wafer mounting stand 30 Lens barrel 31 Lighting unit 32 Half mirror 33a, 33b Objective lens 34 Revolver mechanism 35 Imaging Camera 41 X-axis slider 42 Y-axis slider 43 Rotation mechanism W wafer C device chip DL dicing line (groove / gap)
F Imaging area (field of view)
Rc device area Re peripheral area (near the ridgeline)
L1 Illumination light L2 Light incident from the wafer side (reflected light, scattered light)
T Imaging route

Claims (2)

In a dicing chip inspection device that inspects the device area and the peripheral area of the device chip placed on the diced wafer.
A wafer holding portion for holding the wafer and a wafer holding portion,
An imaging unit that captures a predetermined area set on the wafer at a predetermined imaging magnification, and an imaging unit.
A relative moving unit that moves the wafer and the imaging unit relative to each other,
An inspection recipe registration unit that registers the direction and speed of relative movement in the relative movement unit, and the imaging magnification and imaging position in the imaging unit as inspection recipes.
A control unit that controls the imaging unit and the relative moving unit based on the inspection recipe is provided.
The control unit
A peripheral area inspection mode in which an image is taken along the dicing line so as to include the dicing line of the diced wafer at a predetermined imaging magnification, and the peripheral area of the device chip is inspected.
It is provided with a device area inspection mode in which an image is taken so as to skip the dicing line at an imaging magnification lower than the imaging magnification in the peripheral area inspection mode and the device area is inspected.
The dicing chip inspection device is characterized in that the inspection recipe for executing at least one of the device area inspection mode and the peripheral area inspection mode is registered in the inspection recipe registration unit. In the inspection recipe registration section,
The dicing according to claim 1, wherein the peripheral regions of the plurality of device chips arranged adjacent to each other are set to be simultaneously imaged in a positional relationship such as straddling the dicing line. Chip inspection device.

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