JP6805200B2 - Movement control device, movement control method and movement control program - Google Patents

Description

The present invention relates to a movement control device, a movement control method, and a movement control program that control a plane movement mechanism for moving an object in a plane.

A plane moving mechanism for moving a moving object in a plane is widely used in CT imaging and the like. Many plane moving mechanisms move the moving object in a plane by moving the X table and the Y table in the directions parallel to the orthogonal X-axis and Y-axis, respectively. In such a plane moving mechanism, the X table and the Y table can be reciprocated in each of the X direction and the Y direction, and in general, the driving force of the motor or the like is converted into a force in the linear direction. Make a reciprocating operation.

When a driving force is applied, a mechanism such as a gear or a ball is used. In the mechanism, a backlash (gap) is provided between parts such as a gear or a ball that constitute the mechanism so that the parts can operate smoothly. Is provided. Although the backlash is necessary to form a movable part by a plurality of parts, the influence of the backlash is often different for each of the reciprocating movements, and the positioning accuracy by the plane moving mechanism deteriorates due to the influence of the backlash. ..

Further, when a force is applied to one side of a plane moving mechanism provided with a table that moves in the X direction and the Y direction and no force is applied to the other side parallel to the one side, distortion in the direction parallel to these sides occurs. .. When such distortion occurs, the positioning accuracy by the plane moving mechanism deteriorates. Therefore, various techniques for improving positioning accuracy have been developed. For example, in Patent Document 1, an error from a reference is measured based on the position information detected by the position detection sensor, and the error is taken into consideration. The configuration for creating a tomographic image is disclosed.

Japanese Unexamined Patent Publication No. 2014-115216

Various methods can be considered to improve the positioning accuracy, but if the amount of error changes each time the plane moving mechanism moves, countermeasures against the error become complicated. That is, if an indefinite error is allowed to occur each time the plane movement mechanism moves, it is necessary to take measures such as measuring the error using a position detection sensor as in Patent Document 1 described above. There is. Further, it is necessary to remove the influence of the error (for example, image correction, position correction by the plane moving mechanism, etc.) based on the error of different values generated each time the movement is performed by the plane moving mechanism.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for improving the reproducibility of errors.

A movement control device that controls a plane movement mechanism that moves a movement target in the X direction parallel to the X axis and the Y direction perpendicular to the X axis in order to achieve the above object, and is a vector extending from relay coordinates to target coordinates. The first movement control unit that moves the movement target to the relay coordinates set so that the components in the X direction and the Y direction are non-zero, and the movement target is moved along the vector from the relay coordinates to the target coordinates. A movement control device including a second movement control unit to be moved is configured.

That is, the vector indicating the moving direction from the relay coordinates to the target coordinates has a non-zero component in each of the X direction and the Y direction. The movement control device is configured to move the movement target to the relay coordinates before moving the movement target to the target coordinates by the plane movement mechanism, and move the movement target from the relay coordinates to the target coordinates. Therefore, regardless of the position of the target coordinates, the operation in the X direction and the operation in the Y direction performed to move to the target coordinates are the same.

In the plane moving mechanism, backlash is provided between the parts in each of the moving mechanism in the X direction and the moving mechanism in the Y direction in order to allow the parts to operate smoothly. Therefore, if the effect of backlash caused by the movement direction and movement distance in each of the X and Y directions in the process of moving the movement target to the target coordinates is undefined, an error that occurs when the movement target is moved to the target coordinates. (Hereinafter, it is referred to as "variation in position" or simply "variation") becomes indefinite.

However, in the movement control device, the operation in the X direction and the operation in the Y direction for moving from the relay coordinates to the target coordinates are the same regardless of the position of the target coordinates. Therefore, the operation performed immediately before the movement target moves to the target coordinates is always the same operation. Therefore, the influence on the position variation due to backlash is small. Therefore, it is possible to convert the non-reproducible position variation into a unified reproducible position variation as a whole by a simple configuration and a simple process.

Further, the plane moving mechanism for moving the moving target in the X direction and the Y direction generally includes an X table and a Y table. When each table is moved, a driving force such as a motor acts on each table, but the amount of movement differs between the part where the force is applied and the part where the force is not applied. Therefore, the X table and the Y table are distorted as they move.

Then, if the moving direction and the moving distance in each of the X direction and the Y direction are undefined in the process of moving the moving target to the target coordinates, the distortion generated when the moving target is moved to the target coordinates becomes undefined. The variation in the resulting position is also indefinite.

However, in the movement control device, the operation in the X direction and the operation in the Y direction for moving from the relay coordinates to the target coordinates are the same regardless of the position of the target coordinates. Therefore, the operation performed immediately before the movement target moves to the target coordinates is always the same operation. Therefore, the influence on the position variation due to the distortion is small. Therefore, it is possible to convert the non-reproducible position variation into a unified and repeatable position variation as a whole by a simple configuration and simple processing.

It is a schematic block diagram of the inspection apparatus including a movement control apparatus. FIG. 2A is a diagram schematically showing the configuration of the plane moving mechanism, and FIG. 2B is a schematic diagram showing how the substrate is irradiated with X-rays. It is a figure which shows the target coordinates in the XY plane. It is a flowchart of an X-ray inspection process. It is a figure which shows by replacing the locus of the center of gravity position of a solder bump with an XY plane. 6A and 6B are horizontally sliced reconstructed images of solder bumps showing the difference between the prior art and the present invention.

Here, an embodiment of the present invention will be described in accordance with the following order when X-rays are used for radiation.
(1) Configuration of movement control device:
(2) X-ray inspection processing:
(3) Other embodiments:

(1) Configuration of movement control device:
FIG. 1 is a schematic block diagram of an inspection device including a movement control device according to an embodiment of the present invention. The inspection device includes an X-ray imaging mechanism unit 10 and a control unit 20. The X-ray imaging mechanism unit 10 includes an X-ray generator 11, an X-ray detector 12, and a plane moving mechanism 13. The X-ray imaging mechanism unit 10 is attached to the substrate P by the X-ray generator 11 in a state where the substrate P on the plane moving mechanism 13, the X-ray generator 11 and the X-ray detector 12 have a predetermined relative positional relationship. Irradiate with X-rays.

The X-ray generator 11 includes an X-ray output unit 11a that outputs X-rays, and can irradiate the substrate P with X-rays at a predetermined intensity. The X-ray detector 12 includes a detection surface 12a for detecting the intensity of X-rays, and can take an X-ray image reflecting the amount of X-rays transmitted through the substrate P. The captured X-ray image is recorded in the memory 26 as X-ray image data 26b.

In this embodiment, the substrate P contains solder bumps to be inspected by X-rays. That is, the substrate P includes a processor mounted by a plurality of solder bumps, and in the present embodiment, the solder bumps are to be inspected. The solder bump is moved in a plane in the X-ray irradiation region by moving the substrate P by the plane moving mechanism 13. Therefore, in this embodiment, the solder bump is also a moving target.

The plane moving mechanism 13 can move the moving object two-dimensionally along a predetermined plane (referred to as an XY plane. The X-axis and the Y-axis are perpendicular to each other in the XY plane). It is a possible device, and in this embodiment, the substrate P is moved along the XY plane. FIG. 2A is a diagram schematically showing the configuration of the plane moving mechanism 13 according to the present embodiment. In the present embodiment, the plane moving mechanism 13 includes an X table Tx that moves in the X direction. That is, the X table is a member capable of fixing the substrate P on the upper surface (the surface on the positive direction side of the Z axis), and is attached to the linear rails Rx1 and Rx2 that limit the moving direction of the X table to the X direction parallel to the X axis. Has been done. The linear rails Rx1 and Rx2 are fixed on the Y table.

Further, the plane moving mechanism 13 includes an X-direction drive unit including a motor Mx, a screw shaft Bx, and a coupling portion Jx. The motor Mx is fixed on the Y table, and the screw shaft Bx is rotationally driven by the driving force of the motor Mx. A nut is formed in the joint portion Jx, and the screw shaft Bx is inserted through the nut. A ball is provided between the nut and the screw shaft Bx, and a ball screw is formed by the screw shaft Bx and the joint portion Jx. In this embodiment, a backlash (gap) is provided between the screw shaft Bx, the nut, and the ball so that they can be smoothly driven in combination.

The connecting portion Jx is attached to one side (side Vx parallel to the X direction) constituting the end face in the Y direction in the X table Tx, and the ball screw is not attached to the other end face in the Y direction. Therefore, in the present embodiment, the X-direction drive unit moves the X-table in the X-direction in a state where a force is applied to one side of the X-table Tx in the X-direction and no force is applied to the other end. Let me.

Further, in the X table Tx according to the present embodiment, a sensor Sx for reading the linear scale Lx and the linear scale Lx is attached in the vicinity of the coupling portion Jx. That is, when the X table Tx moves in the X direction as the motor Mx is driven, the movement direction and the movement amount are detected by reading the linear scale Lx by the sensor Sx. Since the linear scale Lx is attached near the coupling portion Jx, in the present embodiment, the linear scale Lx may be attached at a position away from the coupling portion Jx (for example, the side opposite to the side Vx). By comparison, the position can be measured with high accuracy.

Further, the plane moving mechanism 13 includes a Y table Ty that moves in the Y direction. That is, the Y table is a member to which the linear rails Rx1 and Rx2 and the motor Mx are fixed on the upper surface, and is attached to the linear rails Ry1 and Ry2 that limit the moving direction of the Y table to the Y direction parallel to the Y axis. .. The motor My and the linear rails Ry1 and Ry2 are fixed to a housing or the like (not shown) of the inspection device.

Further, the plane moving mechanism 13 includes a Y-direction drive unit including a motor My, a screw shaft By, and a coupling portion Jy. The screw shaft By is rotationally driven by the driving force of the motor My. A nut is formed in the joint Jy, and the screw shaft By is inserted through the nut. A ball is provided between the nut and the screw shaft By, and a ball screw is formed by the screw shaft By and the joint portion Jy. In this embodiment, a backlash (gap) is provided between the screw shaft By, the nut, and the ball so that they can be smoothly driven in combination.

The connecting portion Jy is attached to one side (side Vy parallel to the Y direction) constituting the end face in the X direction in the Y table Ty, and the ball screw is not attached to the other end face in the Y direction. Therefore, in the present embodiment, the Y-direction drive unit moves the Y-table in the Y-direction in a state in which a force is applied to one side of the Y-table Ty in the Y-direction and no force is applied to the other end. Let me.

Further, in the Y table Ty according to the present embodiment, a sensor Sy for reading the linear scale Ly and the linear scale Ly is attached in the vicinity of the coupling portion Jy. That is, when the Y table Ty moves in the Y direction as the motor My is driven, the movement direction and the movement amount are detected by reading the linear scale Ly by the sensor Sy. Since the linear scale Ly is attached near the coupling portion Jy, in the present embodiment, the linear scale Ly is attached at a position away from the coupling portion Jy (for example, the side opposite to the side Vy). By comparison, the position can be measured with high accuracy.

FIG. 2B is a schematic view showing how the substrate P is irradiated with X-rays. In the figure, the horizontal direction is parallel to the XY plane and the vertical direction is perpendicular to the XY plane. It is in the Z direction. In FIG. 2B, the solder bump S on the substrate P, the XY plane Sf, the X-ray output unit 11a of the X-ray generator 11, and the detection surface 12a of the X-ray detector 12 are schematically shown. In the present embodiment, the X-ray output unit 11a is parallel to the Z-axis and outputs X-rays in a range of a predetermined solid angle including the A-axis passing through the focal point of the X-ray output unit 11a. The A-axis is an axis extending parallel to the Z-axis direction in substantially the center of the X-ray output range from the X-ray output unit 11a, and the detection surface 12a of the X-ray detector 12 rotates around the A-axis. In the rotation, the rotation movement is performed while changing the direction of the detection surface 12a so that the straight line L connecting the X-ray output unit 11a and the center of the detection surface 12a and the detection surface 12a are always in a vertical state. (The angle between the A axis and the straight line L is α).

Further, the plane moving mechanism 13 synchronizes the rotational movement of the detection surface 12a with the substrate P so that the solder bump S is arranged on the straight line L connecting the X-ray output unit 11a and the center of the detection surface 12a. Move in the Y plane. That is, when photographing is performed, the detection surface 12a is rotated and the substrate P is moved by the plane moving mechanism 13 so that the detection surface 12a and the solder bump S rotate along the broken line arrow shown in FIG. 2B. .. In the present embodiment, the solder bumps S are photographed at a plurality of imaging positions having different rotation angles around the A-axis, so that X-ray images captured from a plurality of directions are acquired. In the present embodiment, a configuration is proposed in which the substrate P is moved along the rotation locus in the XY plane, but the configuration for moving the substrate P along the rotation locus is an example, and the substrate P is fixed. The X-ray output unit 11a and the detection surface 12a may be rotationally moved.

Next, the control unit 20 will be described. The control unit 20 includes a generator control unit 21, a captured image acquisition unit 22, a photographing mechanism control unit 23, an input unit 24, an output unit 25, a memory 26, and a CPU 27. The memory 26 is a storage medium capable of storing data, and stores program data 26a, X-ray image data 26b, reconstructed image data 26c, target coordinate data 26d, and relay coordinate data 26e. The CPU 27 reads and executes the program data 26a to execute operations for various processes described later. The memory 26 only needs to be able to store data, and various storage media such as RAM, EEPROM, and HDD can be adopted.

The imaging mechanism control unit 23 controls the X-ray generator 11, the X-ray detector 12, and the plane moving mechanism 13, and determines the position of the plane moving mechanism 13 so as to obtain the imaging position and magnification for photographing the X-ray image of the substrate P. The position of the detection surface 12a and the height of the X-ray output unit 11a are adjusted. The plane moving mechanism 13 can arrange an arbitrary position of the substrate P at an arbitrary coordinate in the XY plane based on the outputs of the linear scales Lx and Ly. That is, the initial position of the plane moving mechanism 13 is predetermined, and the photographing mechanism control unit 23 can arrange the X table Tx and the Y table Ty at the initial position based on the outputs of the linear scales Lx and Ly. .. In the present embodiment, when the imaging mechanism control unit 23 is instructed by the CPU 27, which will be described later, to move the target (solder bump S) and the coordinates, the moving target is moved in the XY plane based on the outputs of the linear scales Lx and Ly. It can be moved to the specified coordinates.

The generator control unit 21 controls the X-ray generator 11 to irradiate the substrate P with X-rays from the X-ray generator 11. The captured image acquisition unit 22 acquires X-ray image data 26b indicating an image of the intensity of X-rays detected by the X-ray detector 12, that is, the transmission amount. The X-ray image data 26b is image data composed of gradation values of a plurality of pixels, and the gradation value of each pixel indicates the intensity of X-rays detected by the X-ray detector 12. The reconstructed image data 26c is data showing a three-dimensional image of an inspection target (solder bump S in this embodiment) generated by performing a reconstructed process based on the X-ray image data 26b.

The target coordinate data 26d is information indicating the position where the moving target should be placed when the moving target is photographed by the coordinates in the XY plane. In the present embodiment, the moving target is the solder bump S which is the inspection target by X-rays, and the target coordinate data 26d is the solder bump S which is the moving target at the time of shooting with respect to the information indicating the position on the substrate P of the moving target. The X-coordinate and the Y-coordinate to which the is to be placed are associated.

In the present embodiment, the detection surface 12a is arranged at a plurality of photographing positions having different rotation angles around the A axis, and the solder bump S is photographed at each photographing position. Therefore, the target coordinate data 26d includes a plurality of coordinates indicating the position when the solder bump S is photographed at each photographing position. In this embodiment, these coordinates are referred to as target coordinates. FIG. 3 is a diagram showing target coordinates in the XY plane. In FIG. 3, it is assumed that the detection surface 12a rotates around the A axis and is arranged at eight imaging positions. Therefore, in the example shown in FIG. 3, a total of eight target coordinates D _{1 to} D ₈ are set. As described above, in the present embodiment, the target coordinates are arranged on the circumference of a circle having a constant radius centered on the origin of the XY plane.

The relay coordinate data 26e is information indicating coordinates having a constant relative positional relationship with each of the plurality of coordinates indicated by the target coordinate data 26d. In the present embodiment, the coordinates are referred to as relay coordinates. In the present embodiment, the direction of the target coordinates as seen from the relay coordinates is constant in all the relay coordinates and the target coordinates. Further, the distance between the relay coordinates and the target coordinates is constant in all the relay coordinates and the target coordinates. Therefore, the direction of the vector extending from the relay coordinates to the target coordinates is the same for all of the plurality of target coordinates. The length of the vector extending from the relay coordinates to the target coordinates is the same for all of the plurality of target coordinates.

In the plane moving mechanism 13 according to the present embodiment, a backlash is provided between the screw shaft Bx, the nut, and the ball, and a backlash is provided between the screw shaft By, the nut, and the ball. Therefore, if the relationship between the screw shaft Bx and the nut and the ball or the relationship between the screw shaft By and the nut and the ball is undefined, the driving force of the motors Mx and My acts on the tables Tx and Ty before the table is actually used. The time lag becomes indefinite until Tx and Ty start moving.

In this way, the backlash at the initial stage of the start of movement causes a variation in the position after the completion of the movement. Therefore, if the relationship between the screw shaft Bx and the nut and the ball or the relationship between the screw shaft By and the nut and the ball is undefined immediately before moving the movement target to a plurality of target coordinates, the position where the movement of the movement target is completed. There is no reproducibility in the variation that occurs in. However, if the movement is always performed in a specific direction, the variation in position becomes small, and the variation becomes unified and reproducible as a whole. Therefore, in the present embodiment, the relay coordinate data 26e is set so that the vector extending from the relay coordinate to the target coordinate becomes a constant vector regardless of the position of the target coordinate. In FIG. 3, the vector is indicated by a solid arrow.

Further, in the plane moving mechanism 13 according to the present embodiment, although each of the X table Tx and the Y table Ty is a rigid body, distortion may occur with the movement. That is, in the present embodiment, the driving force of the motor Mx acts on the X table Tx by the coupling portion Jx attached to one side Vx forming the end face in the Y direction. On the other hand, the driving force of the motor Mx does not act on the sides other than the side Vx. Therefore, when the X table Tx moves, the portion near the linear rail Rx1 existing on the side Vx side moves first, while the portion near the linear rail Rx2 existing on the opposite side of the side Vx moves with a slight delay. To do. Therefore, when the X table Tx is moved, distortion occurs in the X direction in the X table Tx. Since the Y table Ty has the same configuration, when the Y table Ty is moved, distortion occurs in the Y table Ty in the Y direction.

Then, if the moving direction and the moving distance in each of the X direction and the Y direction are undefined in the process of moving the moving target to the target coordinates, the distortion generated when the moving target is moved to the target coordinates becomes undefined. The variation in the resulting position is also indefinite. Therefore, in the present embodiment, the relay coordinate data 26e is set so that the vector extending from the relay coordinate to the target coordinate becomes a constant vector regardless of the position of the target coordinate.

In the vector, the components in the X direction and the Y direction are not 0. Therefore, the relay coordinates are set so as to reach the target coordinates after moving in both the X direction and the Y direction. In the present embodiment, the moving speed of the ball screw composed of the motor Mx, the screw shaft Bx, and the connecting portion Jx is the same as the moving speed of the ball screw composed of the motor My, the screw shaft By, and the connecting portion Jy. Therefore, in the present embodiment, a vector inclined by 45 ° with respect to both the X direction and the Y direction is adopted so that the same amount of movement is performed in both the X direction and the Y direction to reach the target coordinates. (See relay coordinates R _{1 with} reference to FIG. 3). That is, the component in the X direction and the component in the Y direction of the vector extending from the relay coordinates to the target coordinates are the same.

Further, the length of the vector, that is, the distance between the relay coordinates and the target coordinates is set so that the backlash is sufficiently eliminated in each of the X direction and the Y direction. For example, the length is set so that at least an order of magnitude is different from the amount of backlash in the X direction. In the present embodiment, the backlash is about several tens of μm, and the length of the vector is about 0.5 mm (therefore, the amount of movement in the X and Y directions is about 0.5 / 2 ^1/2 mm). ..

The output unit 25 is a display for displaying the inspection result of the substrate P and the like, and the input unit 24 is an operation input device that accepts the input of the user. By executing the program indicated by the program data 26a, the CPU 27 controls for photographing the X-ray image data 26b to be inspected and determines the quality of the inspection target. The quality determination is a process for individually determining whether or not the solder bump is defective, and the details will be described later.

When the CPU 27 executes a control program for photographing the X-ray image data 26b to be inspected, the CPU 27 functions as a first movement control unit 27a, a second movement control unit 27b, and a three-dimensional image acquisition unit 27c. Further, when the CPU 27 executes a program for determining the quality, the CPU 27 functions as the quality determination unit 27d.

The first movement control unit 27a executes a function of moving the movement target to the relay coordinates set so that the components in the X and Y directions in the vector extending from the relay coordinates to the target coordinates are non-zero default values. Let me. That is, in the process of moving the moving target to each of the plurality of target coordinates and performing X-ray photography, the CPU 27 moves the moving target to the relay coordinates before moving the moving target to each target coordinate.

Therefore, the CPU 27 generates the relay coordinate data 26e based on the target coordinate data 26d. That is, the CPU 27 acquires a plurality of target coordinates based on the target coordinate data 26d by the function of the first movement control unit 27a, and the direction and distance of the vector extending from the relay coordinates corresponding to each target coordinate to each target coordinate are determined. Set the relay coordinates so that they are constant. According to the above process, for example, relay the coordinates R ₁ to R ₈ corresponding to the respective target coordinate D ₁ to D ₈ are set in the example illustrated in FIG.

Therefore, the CPU 27 moves the moving target to the relay coordinate R _n corresponding to the target coordinate D _n before moving the moving target to the target coordinate D _n (n is an integer value of 1 to the maximum number of times of shooting). Therefore, when the moving target is moved to the relay coordinates R _n , the CPU 27 outputs the relay coordinates R _n to the photographing mechanism control unit 23 together with the position of the solder bump S which is the moving target on the substrate P. As a result, the photographing mechanism control unit 23 controls the plane moving mechanism 13 to move the moving target to the relay coordinates R _n .

The second movement control unit 27b causes the CPU 27 to execute a function of moving the movement target from the relay coordinates to the target coordinates. That is, the CPU 27 outputs the target coordinates D _n to the imaging mechanism control unit 23 together with the position of the solder bump S to be moved on the substrate P. As a result, the photographing mechanism control unit 23 controls the plane moving mechanism 13 to move the moving target to the target coordinates D _n .

The three-dimensional image acquisition unit 27c is a function of irradiating the moving object (solder bump S) moved to the photographing position with X-rays to acquire the three-dimensional image of the moving object. That is, the CPU 27 instructs the generator control unit 21 to generate X-rays having a predetermined intensity at each imaging position by the function of the three-dimensional image acquisition unit 27c. The generator control unit 21 controls the X-ray generator 11 based on the instruction, and causes the X-ray generator 11 to irradiate the solder bump S with X-rays.

In this state, the CPU 27 instructs the captured image acquisition unit 22 to capture an X-ray image. The captured image acquisition unit 22 acquires the X-ray image data output by the X-ray detector 12 based on the instruction, and records it in the memory 26 as the X-ray image data 26b. When the X-ray image data 26b is acquired at all of the plurality of imaging positions, the CPU 27 refers to each X-ray image data 26b and generates a three-dimensional image of the solder bump. Specifically, the CPU 27 executes a reconstruction operation based on the X-ray image data 26b obtained by photographing each solder bump from a plurality of positions to generate a three-dimensional image. The information indicating the generated three-dimensional image is recorded in the memory 26 as the reconstructed image data 26c.

The quality determination unit 27d is a function of determining the quality of the solder bump S to be inspected based on the reconstructed image data 26c. That is, the CPU 27 refers to the reconstruction information indicated by the reconstruction image data 26c by the processing of the pass / fail determination unit 27d, and based on the reconstruction information, the solder bump S is cut in the direction perpendicular to the Z axis. Obtain a tomographic image of. Then, the CPU 27 compares the tomographic image with a predetermined determination condition (for example, a condition indicating a quality criterion based on the presence / absence of a void, the size, shape, position, etc. of the void), and determines the quality based on the determination condition. ..

According to the above configuration, in the process of moving the moving target to each of the plurality of target coordinates and taking an X-ray image, the moving target must be passed through the relay coordinates before being moved to each target coordinate, and all the targets. The moving target can be placed at the target coordinates after moving toward the coordinates in the same direction and by the same distance. Therefore, the operation performed immediately before the movement target moves to the target coordinates is always the same operation, and even if the position variation due to backlash or the position variation due to the distortion of the X table Tx and the Y table Ty occurs, the position variation occurs. The variation with respect to the target coordinates is small, and the variation has repeatability. Therefore, it is possible to correct the position of the plane moving mechanism by a simple configuration or a simple process for a positional deviation in which the direction and the distance that constantly occur are constant.

(2) X-ray inspection processing:
FIG. 4 is a flowchart showing an X-ray inspection process. The inspection device executes the X-ray inspection process shown in FIG. 4 in order to inspect the solder bump S. When the X-ray inspection process is started, the CPU 27 acquires a vector component by the function of the first movement control unit 27a (step S100). That is, the components ΔX and ΔY in the X and Y directions of the vector extending from the relay coordinates to the target coordinates are default values and are recorded in the memory 26 or the like. The CPU 27 acquires the components ΔX and ΔY of the vector with reference to the memory 26 and the like. In the example shown in FIG. 3, ΔX and ΔY have the same negative values.

Next, the CPU 27 performs a process for acquiring the target coordinates by the function of the second movement control unit 27b. Specifically, the CPU 27 acquires the vertical distance FOD between the focal point of the X-ray and the center of gravity of the moving target by the function of the second movement control unit 27b (step S105). In the present embodiment, the height (position in the Z direction) of the plane moving mechanism 13 is fixed, and the height of the X-ray output unit 11a can be adjusted. Therefore, the CPU 27 acquires the distance in the Z direction between the focus of the X-ray in the X-ray output unit 11a and the substrate P fixed to the plane moving mechanism 13 based on the height of the X-ray output unit 11a, and is vertical. Considered as a distance FOD (see FIG. 2B). The vertical distance FOD may be measured by a sensor or the like, or may be specified by an indicated value or the like for instructing the height of the X-ray output unit 11a, and may be calculated by various methods.

Next, the CPU 27 acquires the distance FOD _α between the focal point of the X-ray and the center of gravity of the moving target based on the tilt angle α at the time of shooting by the function of the second movement control unit 27b (step S110). That is, the CPU 27 acquires the angle α between the straight line L connecting the focal point of the X-ray and the center of the detection surface 12a and the A axis. Here, too, the angle α has various configurations such as a configuration measured by a sensor, a configuration specified by an indicated value for instructing the height of the X-ray output unit 11a, a design value of the plane moving mechanism 13, and the like. May be adopted. When the angle α is acquired, the CPU 27 calculates FOD / cos _α and considers it as the distance FOD _α (see FIG. 2B).

Next, the CPU 27 acquires the angle change Δθ for each shooting based on the number of shootings N by the function of the second movement control unit 27b (step S115). That is, in the present embodiment, the number of times of shooting N is predetermined, and the CPU 27 acquires 360 / N as the angle change Δθ of the detection surface 12a per one time. In the example shown in FIG. 3, since N = 8, the angle change Δθ is 45 °.

Next, the CPU 27 acquires the rotation angle θ _{k in the kth} shooting by the function of the second movement control unit 27b (step S120). That is, the CPU 27 acquires the rotation angle θ _k of the detection surface 12a at each of k when k = 1 to N. Specifically, the CPU 27 acquires θ ₀ + Δθ (k-1) as θ _k when the initial value of the rotation angle of the detection surface 12a is θ ₀ . The reference of the angle may be determined in advance, and in FIG. 3, the direction parallel to the X axis is the reference and is 0 °. Further, in FIG. 3, a case where θ ₀ is 45 ° is illustrated. In this example, since the angle change Δθ is also 45 °, the rotation angle θ _{1 in the first} shooting is the angle rotated 90 ° counterclockwise from the X axis, and the rotation angle θ ₂ in the second shooting is X. It is the angle rotated 135 ° counterclockwise from the axis.

Next, the CPU 27 acquires the target coordinates D _k (X _k , Y _k ) at the rotation angle θ _k by the function of the second movement control unit 27b (step S125). In the present embodiment, the moving object moves on the circumference of the circle in the XY plane. The radius of the circle is the distance FOD _α × sin _α between the focal point of the X-ray and the center of gravity of the moving object. Further, the rotation angle with respect to the A axis of the movement target on the XY plane and the rotation angle θ _k of the detection surface 12a are the same, so that the CPU 27 sets each of k when k = 1 to N. X _k = FOD _α × sin α × cos θ _k
Y _k = FOD _α × sin _α × sin θ _k
Then, the target coordinates D _k (X _k , Y _k ) are acquired.

The relay coordinates _{R k (X 'k, Y} ' k) in the rotation angle theta _k to get (step S130). That is, the CPU 27 adds the inverse vector of the vector acquired in step S100 to each target coordinate D _k (X _k , Y _k ) acquired in step S125, so that the relay coordinates R _k ( _X'k , Y'). get _k ). Specifically, CPU 27 is, X in each of the k in the case where a _{k = 1~N 'k = X k} -ΔX
Y _'k = Y _k -ΔY
Then, the relay coordinates R _k ( _X'k , _Y'k ) are acquired.

Next, the CPU 27 photographs the solder bump S by the functions of the first movement control unit 27a, the second movement control unit 27b, and the three-dimensional image acquisition unit 27c. Specifically, the CPU 27 initializes k, which is a variable for counting the number of times of shooting, to 1 by the function of the three-dimensional image acquisition unit 27c, and moves the movement target to the origin 0 in FIG. 3 (step S135). Further, the CPU 27 sets the rotation angle to θ _k by the function of the three-dimensional image acquisition unit 27c (step S140). That is, the CPU 27 instructs the photographing mechanism control unit 23 to rotate the rotation angle θ _k . As a result, the imaging mechanism control unit 23 controls the X-ray detector 12 and changes the detection surface 12a to the rotation angle θ _k . As a result, the rotation angle of the detection surface 12a changes from the rotation angle θ _{k-1 in the k-1st} imaging to the rotation angle θ _k in the _kth imaging. When k is 1, the rotation angle is θ _0, which is an initial value of the rotation angle of the detection surface 12a.

For example, when k is 1 in the example shown in FIG. 3, the rotation angle θ ₀ changes to the rotation angle θ ₁ in step S140. Therefore, the detection surface 12a is set at a shooting position for shooting the target coordinate D ₁ . When k is 2 in the example shown in FIG. 3, the rotation angle θ ₁ is changed to the rotation angle θ ₂ by step S140. Therefore, the detection surface 12a is set at a shooting position for shooting the target coordinate D ₂ .

Next, the CPU 27 moves the movement target to the relay coordinates R _k by the function of the first movement control unit 27a (step S145). That is, the CPU 27 outputs the relay coordinates R _k acquired in step S130 together with the position of the solder bump S on the substrate P to the imaging mechanism control unit 23. As a result, the photographing mechanism control unit 23 controls the plane moving mechanism 13 to move the moving target to the relay coordinate R _k . For example, in the example shown in FIG. 3, when k is 1, the solder bump S moves from the coordinates of the origin 0 to the relay coordinate R ₁ as shown by the solid line L ₁ in FIG. 3, and when k is 2, the solder bump S moves. As shown by the solid line L ₂ in FIG. 3, S moves from the target coordinate D ₁ to the relay coordinate R ₂ . The solid line showing the movement from the target coordinate D _k-1 to the relay coordinate R _k shown in FIG. 3 shows only the relay coordinate R ₂ , but the same operation is repeated when k is 3 to 8.

Next, the CPU 27 moves the movement target to the target coordinate D _k by the function of the second movement control unit 27b (step S150). That is, the CPU 27 outputs the target coordinates D _k acquired in step S125 together with the position of the solder bump S on the substrate P to the imaging mechanism control unit 23. As a result, the photographing mechanism control unit 23 controls the plane moving mechanism 13 to move the moving target to the target coordinate D _k . For example, when k is 1 in the example shown in FIG. 3, the solder bump S moves along a vector extending from the relay coordinate R ₁ to the target coordinate D ₁ as shown by the solid arrow in FIG. 3, and k is 2. In the case of, it moves along a vector extending from the relay coordinate R ₂ to the target coordinate D ₂ .

Then, CPU 27 by the function of the three-dimensional image obtaining unit 27c, obtains the k-th captured image data I _k (step S155). That is, the CPU 27 instructs the captured image acquisition unit 22 to capture an X-ray image. The captured image acquisition unit 22 acquires the X-ray image data output by the X-ray detector 12 based on the instruction, associates k indicating the number of times of imaging, and records it in the memory 26 as the X-ray image data 26b.

Next, the CPU 27 increments k (step S160) by the function of the three-dimensional image acquisition unit 27c, and determines whether or not k is the number of times of shooting N or less (step S165). If it is not determined in step S165 that k is not less than or equal to the number of times of shooting N, the CPU 27 repeats the processes after step S140.

When it is determined in step S165 that k is the number of times of shooting N or less, the CPU 27 executes the reconstruction calculation process by the function of the three-dimensional image acquisition unit 27c (step S170). As for the reconstruction operation, it is sufficient that the three-dimensional structure of the solder bump S can be reconstructed, and various processes can be adopted. For example, the filter correction back projection method can be adopted. In this process, the CPU 27 first performs a Fourier transform on any of the plurality of X-ray images, and multiplies the result obtained by the Fourier transform by a filter correction function in the frequency space. Further, by performing an inverse Fourier transform on this result, a filter-corrected image is acquired. As this filter correction function, a function or the like for emphasizing the edge of the image can be adopted.

Subsequently, the filter-corrected image is back-projected into the three-dimensional space along the trajectory on which it is projected. That is, since the locus corresponding to the image of a certain position on the detection surface 12a of the X-ray detector 12 is a straight line connecting the focal point of the X-ray generator 11 and this position, the image is back-projected on this straight line. When the above back projection is performed on all of a plurality of X-ray images, the X-ray absorption coefficient distribution of the portion where the reference sample exists in the three-dimensional space is emphasized, and the reconstruction information indicating the three-dimensional shape of the reference sample is shown. Is obtained. The generated reconstruction information is recorded in the memory 26 as the reconstruction image data 26c.

Next, the CPU 27 executes the pass / fail determination process by the function of the pass / fail determination unit 27d (step S175). That is, in the present embodiment, the feature amount for determining the quality of the solder bump S is defined in advance, and the CPU 27 has the feature amount of the solder bump S based on the reconstructed image data 26c generated in step S170. To get. As the feature amount, various amounts can be adopted, and examples thereof include the size and shape of voids in the solder bumps. A threshold value for determining the quality of the feature amount is set in advance, and the CPU 27 inspects the quality of the solder bump by comparing the feature amount with the threshold value. Further, the CPU 27 causes the output unit 25 to output the quality determination result of the solder bump S.

In the present embodiment, before moving the solder bump S to each target coordinate, the process of moving the solder bump S to the target coordinate by always passing through the relay coordinate and moving the solder bump S by the same distance in the same direction to the target coordinate is performed. To run about. As a result, the variation due to the backlash and the distortion caused by the movement of the X table Tx and the Y table Ty becomes the variation of the position having reproducibility repeatedly.

FIG. 5 is a diagram showing a locus of the center of gravity of the solder bump. In FIG. 5, the locus of the center of gravity of the solder bump photographed on the detection surface 12a is shown by the locus replaced with the coordinates of the XY plane shown in FIG. However, although FIG. 3 has been described with the number of times of imaging N being 8 in order to facilitate understanding of the present invention, FIG. 5 clarifies the difference between the locus when affected by backlash by the prior art and the locus of the present invention. The number of shots N was expressed using 32, which is the actual number of shots.

In FIG. 5, the coordinates of the center of gravity at the target coordinate D _k of the solder bump when the solder bump S is moved from the relay coordinate R _k to the target coordinate D _k as in the present embodiment are between δ _r and the target coordinate D _k . The coordinates of the center of gravity of the solder bumps according to the prior art when the solder bumps S are directly moved without passing through the relay coordinates R _k are shown as δ _d . Further, the coordinates δ _r and δ _d of the center of gravity of the solder bump indicate the coordinates of the center of gravity of the solder bump with respect to the number of times of shooting. As shown in FIG. 5, the center of gravity of the coordinate _{δ r1 ~δ r32, δ d1 ~δ} d32 , in response to the number of shots 1-32 solder bumps S is moved on the circumference in the X-Y plane annular Changes to.

In FIG 5, the coordinates [delta] _r1 locus of ～Deruta _r32 of the center of gravity of the solder bumps of the present invention when moving the solder bumps S from the relay coordinates R _k to the target coordinates D _k by the solid line, the relay coordinates R _k shows the locus of the coordinate δ _d1 ~δ _d32 of the center of gravity of the solder bumps according to the prior art when moving the solder bumps S to the target coordinates D _k without resort directly by a broken line. Further, horizontally sliced reconstructed images of the solder bumps obtained by the respective loci of FIG. 5 are shown in FIGS. 6A and 6B, respectively. FIG. 6A shows a horizontally sliced reconstruction image of the solder bumps according to the prior art, and FIG. 6B shows a horizontally sliced reconstruction image of the solder bumps according to the present invention. As is clear from FIG. 5, the coordinate δ _r of the center of gravity of the solder bump when it is moved to the target coordinate via the relay coordinate has a trajectory close to a circle and is a clear bump as shown in FIG. 6B. Image is obtained. On the other hand, when the solder bump S is moved to the target coordinate D _k without going through the relay coordinate R _k , the coordinate δ _d of the center of gravity of the solder bump has a very different trajectory, which is not shown in FIG. 6A. An image of bumps with a stable shape can be obtained. As described above, by moving from the relay coordinate R _k to the target coordinate D _k, a clear image of the inspection target is generated.

In the embodiment, it has been explained that the reconstruction operation is executed directly from the acquired X-ray image data, but when the variation itself of the target coordinates is undecided, for example, "at the time of introduction of the inspection device" or "regular maintenance". At "time", the process of correcting the variation in the target coordinates may be executed first. Specifically, after step S165 in FIG. 4, the variation in the target coordinates shown in FIG. 5 (positional deviation with respect to each target coordinate on the circumference) is measured and determined, and the variation in the overall or specific target coordinates is large. If it is determined that, the position deviation with respect to a specific direction and distance is corrected by correcting the value of the target coordinates so that the trajectory of the target coordinates approaches the coordinates on the circumference with a constant radius centered on the origin. The reconstruction operation may be executed based on the images taken at the target coordinates.

(3) Other embodiments:
The above embodiment is an example for carrying out the present invention, and various other embodiments can be adopted as long as the moving object is moved to the relay coordinates and then to the target coordinates. For example, the movement control device may be provided in a device other than the X-ray inspection device shown in FIG. The movement control device only needs to be able to control a plane movement mechanism that moves the movement target in the X direction parallel to the X axis and the Y direction perpendicular to the X axis. Therefore, as in the above-described embodiment, it may be configured by a CPU or the like indirectly connected to the plane moving mechanism via the imaging mechanism control unit, or a controller directly connected to the plane moving mechanism. It may be configured by the above, and various configurations can be adopted.

The plane moving mechanism may move the moving object in the X direction parallel to the X axis and the Y direction perpendicular to the X axis. Therefore, various configurations may be adopted in addition to the configuration in which the moving target is arranged and moved on the X table. For example, the moving object fixed at a position at the same height as the X table or the Y table may move in a plane, or the moving object fixed below the X table or the Y table moves in a plane. It may be configured.

Further, the plane moving mechanism can move the moving object in the X direction parallel to the X axis and the Y direction perpendicular to the X axis. That is, the moving target can be moved independently in each of the X direction and the Y direction. The configuration for moving the moving target in each of the X direction and the Y direction is not limited to the configuration in which the driving force of the motor is converted into a force in the linear direction by the ball screw as described above. Therefore, a configuration in which the force is transmitted to the plane moving mechanism by various gears or the like may be used, and various configurations can be adopted.

The moving object may be movable in at least a plane, and may be moved in another direction (for example, a direction perpendicular to the plane or a direction of rotation in the plane). Further, the X-axis and the Y-axis may be vertical in the plane in which the moving object moves. The moving target may be any target that is moved in a plane, and is not limited to the inspection target that is inspected by the three-dimensional reconstruction operation as described above. For example, when the detector is moved in a plane in the inspection device, the detector may be the target of movement.

The first movement control unit may move the movement target to the relay coordinates set so that the components in the X direction and the Y direction in the vector extending from the relay coordinates to the target coordinates are non-zero default values. That is, when moving the moving target to the target coordinates, the moving target is not moved directly with respect to the target coordinates, but is moved to the relay coordinates having a specific positional relationship with respect to the target coordinates before the target. It suffices if it is configured to move to the coordinates.

The relay coordinates may be any default value in which the components in the X and Y directions of the vector extending from the relay coordinates to the target coordinates are non-zero. That is, when moving the movement target from the relay coordinates to the target coordinates, it may be configured to move in both the X direction and the Y direction. The components in the X and Y directions, that is, the moving distances in the X and Y directions may be fixed values that are predetermined, and may be the same or different in the X and Y directions. May be good.

The default value may be predetermined, but since the vector has the component of the default value, it is configured so that the error after moving in the X direction and the Y direction does not vary. Is preferable. Therefore, it is preferable that the value is larger than the magnitude of backlash and strain. For example, it is preferable that the default value is determined so that the movement is performed by an amount of an order of magnitude or more larger than the magnitude of backlash or distortion.

The second movement control unit only needs to be able to move the movement target from the relay coordinates to the target coordinates along the vector. That is, it suffices if the movement target can be linearly moved from the relay coordinates to the target coordinates. For this purpose, the second movement control unit only needs to be able to move the moving target in the X direction and the Y direction at the same time. For example, when the default value which is the component in the X direction of the vector extending from the relay coordinates to the target coordinates and the default value which is the component in the Y direction are the same, the second movement control unit is the same in the X direction and the Y direction. It moves along a vector by moving at a speed. When the default value that is the component in the X direction and the default value that is the component in the Y direction are different, for example, the velocity ratio equal to the ratio of the default value that is the component in the X direction and the default value that is the component in the Y direction. It may be moved in the X direction and the Y direction.

The application target of the present invention is not limited to the device, and it is assumed that it will be realized as a method or a program. Further, the movement control device as an embodiment of the present invention may be realized independently, may be applied to a certain method, or the same method may be used in a state of being incorporated in another device. The idea of the invention is not limited to this, and includes various aspects. Of course, the embodiment of the invention may be software or hardware, and can be changed as appropriate. Further, the recording medium of the software may be a magnetic recording medium or a semiconductor memory, and any recording medium to be developed in the future can be considered in exactly the same manner. The same applies to the duplication stage of the primary replica and the secondary replica. Further, even if a part is software and a part is realized by hardware, it is not completely different in the idea of the invention, and a part is stored on a recording medium and appropriately as needed. It may be in a form that is read.

10 ... X-ray imaging mechanism, 11 ... X-ray generator, 11a ... X-ray output, 12 ... X-ray detector, 12a ... Detection surface, 13 ... Plane movement mechanism, 20 ... Control unit, 21 ... Generator control Unit, 22 ... Photographed image acquisition unit, 23 ... Photographing mechanism control unit, 24 ... Input unit, 25 ... Output unit, 26 ... Memory, 26a ... Program data, 26b ... X-ray image data, 26c ... Reconstructed image data, 26d ... Target coordinate data, 26e ... Relay coordinate data, 27 ... CPU, 27a ... First movement control unit, 27b ... Second movement control unit, 27c ... Three-dimensional image acquisition unit, 27d ... Good / bad judgment unit

Claims (4)

A movement control device that controls a plane movement mechanism that sets an inspection target based on a reconstructed image of an X-ray image as a movement target and moves the movement target in the X direction parallel to the X axis and the Y direction perpendicular to the X axis. hand,
A first movement control unit that moves the movement target to the relay coordinates set so that the components in the X direction and the Y direction in the vector extending from the relay coordinates to the target coordinates are non-zero default values.
A second movement control unit that moves the movement target from the relay coordinates to the target coordinates along the vector is provided.
The target coordinates are a plurality of coordinates in which the inspection target is arranged when the same inspection target is photographed at each of a plurality of imaging positions, and the relay coordinates corresponding to each of the plurality of target coordinates exist. And
The vectors in all of the plurality of the target coordinates are the same, and a said X-direction component in all of the vectors identical, Ri the Y direction component identical der in all of the vector,
In the plane moving mechanism, backlash is provided between the parts of the moving mechanism in the X direction, and the default value which is a component in the X direction in the vector is one digit or more larger than the amount of backlash. ,
In the plane moving mechanism, backlash is provided between the parts of the moving mechanism in the Y direction, and the default value which is a component in the Y direction in the vector is one digit or more larger than the amount of backlash. ,
Movement control device. The plane moving mechanism is
The X table that moves in the X direction and
X that moves the X table in the X direction in a state where a force in the X direction is applied to one end of the X table in the Y direction and no force is applied to the other end. Directional drive and
The Y table that moves in the Y direction and
Y that moves the Y table in the Y direction in a state where a force in the Y direction is applied to one end of the Y table in the X direction and no force is applied to the other end. With a directional drive unit,
The movement control device according to claim 1. It is a movement control method that controls a plane movement mechanism that moves an inspection target based on a reconstructed image of an X-ray image as a movement target and moves the movement target in the X direction parallel to the X axis and the Y direction perpendicular to the X axis. hand,
A first movement control step of moving the movement target to the relay coordinates set so that the components in the X direction and the Y direction in the vector extending from the relay coordinates to the target coordinates are non-zero default values.
A second movement control step of moving the movement target from the relay coordinates to the target coordinates along the vector is included.
The target coordinates are a plurality of coordinates in which the inspection target is arranged when the same inspection target is photographed at each of a plurality of imaging positions, and the relay coordinates corresponding to each of the plurality of target coordinates exist. And
The vectors in all of the plurality of the target coordinates are the same, and a said X-direction component in all of the vectors identical, Ri the Y direction component identical der in all of the vector,
In the plane moving mechanism, backlash is provided between the parts of the moving mechanism in the X direction, and the default value which is a component in the X direction in the vector is one digit or more larger than the amount of backlash. ,
In the plane moving mechanism, backlash is provided between the parts of the moving mechanism in the Y direction, and the default value which is a component in the Y direction in the vector is one digit or more larger than the amount of backlash. ,
Movement control method. A computer that controls a plane moving mechanism that sets an inspection target based on a reconstructed image of an X-ray image as a moving target and moves the moving target in the X direction parallel to the X axis and the Y direction perpendicular to the X axis.
A first movement control unit that moves the movement target to the relay coordinates set so that the components in the X direction and the Y direction in the vector extending from the relay coordinates to the target coordinates are non-zero default values.
The movement target is made to function as a second movement control unit that moves the movement target from the relay coordinates to the target coordinates along the vector.
The target coordinates are a plurality of coordinates in which the inspection target is arranged when the same inspection target is photographed at each of a plurality of imaging positions, and the relay coordinates corresponding to each of the plurality of target coordinates exist. And
The vectors in all of the plurality of the target coordinates are the same, and a said X-direction component in all of the vectors identical, Ri the Y direction component identical der in all of the vector,
In the plane moving mechanism, backlash is provided between the parts of the moving mechanism in the X direction, and the default value which is a component in the X direction in the vector is one digit or more larger than the amount of backlash. ,
In the plane moving mechanism, backlash is provided between the parts of the moving mechanism in the Y direction, and the default value which is a component in the Y direction in the vector is one digit or more larger than the amount of backlash. ,
Movement control program.