KR101273094B1 - The measurement method of PCB bump height by using three dimensional shape detector using optical triangulation method - Google Patents

Abstract

The present invention relates to a PCB bump height measurement method using a three-dimensional shape measuring device using the optical triangulation method, (a) is configured symmetrically in a computer vision system connected to semiconductor inspection equipment and optical sensor controller, such as BGA, FC, CSP Scanning a laser beam through a lens inclined at a predetermined angle from a left (L) or right (R) laser optical system, respectively, into one laser optical system or a ball of a bump of an IC chip at the same time, and dual scanning; (b) When one of the laser beams from the left (L) or right (R) laser optical system is scanned on the IC chip, the IC is used by the optical triangulation method according to the change in the length of the image formed by detecting reflected light by the CCD camera and the optical sensor. Measuring the height of bumps of the IC chip according to the change in the height of the curved surface of the bumps of the chips; And (c) calculating the heights of the balls of each bump of the IC chip using the arithmetic mean of the height values of the balls of the bumps of the two IC chips measured simultaneously with the right (R) and left (L) laser beams. Steps. According to the present invention, the BGA, FC, or CSP Ball to be measured can be selectively or simultaneously scanned according to a relative position of a CCD camera and a laser beam by using an optical measuring sensor of a semiconductor inspection device and a laser optical system in two directions. When the R and L lasers were simultaneously measured for the bump balls, the height of the bumps of the bumps of the IC chip was determined by the arithmetic mean value so that the bump height of the bumps of the IC chip was more accurately measured.

Description

The measurement method of PCB bump height by using three dimensional shape detector using optical triangulation method}

The present invention relates to a PCB bump height measurement method using a three-dimensional shape measuring device, and in particular, bidirectional symmetrical laser using BGA (Ball Grid Array), FC (Flip Chip), CSP (Chip Scale Package) inspection equipment The laser beam is simultaneously scanned by the ball of the IC chip's bump through a lens of an angle, and the dual scanning is performed to measure the bump height of the IC chip. The present invention relates to a PCB bump height measurement method using a three-dimensional shape measuring device using an optical triangulation method to improve the accuracy of ball height measurement.

The three-dimensional shape measurement method used in semiconductor inspection equipment, movie special effects using computer graphics, and 3D scanner technology includes (1) a point beam projection method using a point light, and (2) a slit ( Slit) 3D shape measurement method using light, (3) 3D shape measurement method using spatial coding, (4) 3D shape measurement method using Moire.

3D scanner technology uses point triangulation based optical projection, slit optical projection, and spatial encoding method. It is a method to simultaneously project a large number of gratings and phase shift them to improve measurement resolution. (Moire) method and PMP (Phase Measuring Profilometry) method are used.

(1) Point beam projection method using point light is the most basic form of 3D measurement. A three-dimensional shape of a measurement object on a surface is measured using an optical displacement sensor using a conventional touch probe.

The optical displacement sensor collects a laser beam emitted from a laser diode at a predetermined angle on a surface thereof with a luminous lens (condenser lens) having a focal distance of about 5 mm and irradiates the laser beam source passing therethrough to a measurement object on the surface.

The laser light source reflected from the object to be measured is again received by an image-forming lens (light-receiving lens) and imaged on a CCD (Charge Coupled Device) sensor or an optical PSD (Position Sensing Detector) sensor. The PSD sensor outputs an electrical signal according to the imaging position. Here, the PSD sensor measures the height value of one point because the position where the image is formed on the PSD sensor changes according to the height variation of the measurement object.

Since the optical displacement sensor measures only the height value of one point of the measurement object on the surface at a time, when measuring the curved shape of the measurement object on the surface, the three-dimensional position coordinate value of the optical displacement sensor while moving the optical displacement sensor at the same time Because of the need for reading, a highly accurate movable mechanism is required.

Optical displacement sensors are available in many products, but the measurement accuracy of the commonly used sensors is about 2-5㎛.

(2) Slit Beam Projection using Slit Light

The three-dimensional shape measurement method using slit light is a measurement method based on the principle of the optical triangulation method. The slit light focuses the laser light from the laser diode to the condenser lens, and the rod lens or the cylindrical lens. I make a slit light

In the three-dimensional shape measurement method using slit light, the slit light is incident on the measurement object to obtain the slit light modified according to the shape of the measurement object, and the slit light is modified by the CCD camera to obtain the shape of the measurement object from the geometric relationship. It is a method of calculating the three-dimensional coordinates of. In this method, two methods are used to measure and move the measurement cross section using a mechanical drive system to measure the overall shape of the object to be measured.

In the first method, the laser slit light is reflected on the mirror and the slit light is scanned by measuring the angle of the mirror by using a galvanometer. This type of measuring optical system has a very simple optical configuration compared to the spatial coding method, the Moire method, and the Phase Measuring Profilometry (PMP) method. The planar equation of the direction in which the slit light travels and the CCD camera image pixel Find the intersection of the linear equations and measure the height profile. The measurement resolution and precision of the slit light greatly depend on the thickness of the slit light and the degree of slit light and camera correction.

The second method is to integrate the camera and the slit light into a mechanism that can move with high precision, and most products use this method.

(3) 3D shape measurement method using spatial coding

The three-dimensional shape measurement method using spatial coding is based on the principle of optical triangulation with slit light. In the three-dimensional shape measurement method using spatial coding, a liquid crystal device or a film is mounted on a projection optical system used at a seminar time using a beam projector and scanned on a measurement object.

The three-dimensional shape measurement method using spatial coding first uses a large grid and then scans several times while reducing the width by 1/2. In order to find out which number of slit lights is obtained by sequentially checking whether light is on (ON) or off (OFF) in the scanned images, the height value is determined from the intersection of the plane equation and the linear equation of the image sensor. Is the way to obtain.

For example, the three-dimensional shape measurement method using slit light requires capturing and interpreting 256 images when projecting 256 slit light, whereas the three-dimensional shape measurement method using spatial coding method is 8 (28 =). It is effective compared to slit light because it captures 256 images.

(4) 3D shape measurement method using moire

In the shadow moire method, a regular striped grid is placed directly in front of the measurement object and light is emitted from one side so that the shadow of the grid is formed on the measurement object. This shadow will bend according to the shape of the workpiece.

In this state, when looking at the measured object from the other side, the shape information of the object is analyzed by using the undeformed straight line grid and the moire pattern representing the wavy contour pattern while the shadow of the grid overlaps. You get the height value.

Such a moire pattern enables a more precise shape measurement because the denser moiré can be obtained as the pitch of the grid used is reduced. However, the projection moiré method is used because the lattice must be phase-shifted in order to know the height direction in the formed moire fringes, and precise lattice as large as the size of the measurement object is required.

Projection-type moiré method can obtain a very accurate measurement accuracy compared to other measurement methods because the phase shifting of the grating for the precise analysis of moire fringes, but the optical system has a disadvantage of becoming very complicated, it has not yet been popularized.

1A is a view for explaining the principle of the conventional optical triangular method.

In the BGA inspection equipment or FC (Flip Chip) and CSP (Chip Scale Package) semiconductor inspection equipment, the three-dimensional shape measuring apparatus includes a laser beam focused on a light emitting lens from a laser diode as shown in FIG. A light source) is incident on the surface of the measurement object, and the laser light reflected from the height of the curved surface of the measurement object is formed into an optical lens on the image pickup surface of the CCD using an optical triangulation. The height of the measurement object is measured. At this time, the position of the light spot formed on the CCD imaging surface changes according to the height change of the measurement object, and the height of one point of the measurement object corresponding to the light point is obtained from the position change of the light spot.

The three-dimensional shape measuring device of the semiconductor inspection equipment is irradiated with the ball laser light of the measurement object to measure the surface defects of the balls of the bumps of the IC chip, and then at that position of the balls of the bumps. It is deformed in the vertical direction of the reference plane by the height information of. This line-shaped optical image deformed in accordance with the three-dimensional surface shape change is acquired by a CCD camera positioned at an angle with respect to the reference plane. The height information of each position is extracted from the obtained image of the ball of the bump of the IC chip while moving the measurement object (ball of the bump of the IC chip) by the transfer device over time. Then, the surface defect of the IC chip bump is determined according to the change of the height of the ball of the IC chip bump.

As shown in Fig. 1A, the principle of the displacement measurement method of optical triangulation is that the small laser light spot irradiated on the plane of the measurement object is placed on the plane of the optical position measurement sensor PSD by the incident laser beam axis and the inclined lens F. When the image is formed and the position of the measurement object is changed in the h direction, the position of the PSD image of the laser light spot is changed by d. The three-dimensional measuring apparatus of the semiconductor inspection equipment measures this d value and measures the height h of the measurement object (ball of the bump of the IC chip) by substituting and converting the optical system variable.

2 is a view for explaining the function of the three-dimensional shape measurement apparatus using the optical triangulation method.

The three-dimensional shape measuring apparatus used as a conventional semiconductor inspection equipment using the optical triangulation method is a computer vision system (computer vision system) and an optical sensor controller (LAN) is connected to the LAN card and TCP / IP or RS232C serial communication method, the controller When the laser is scanned only in one direction from the CCD camera connected to the measuring object (a ball of the bump of the IC chip) placed directly below the vertical line, the conventional structured laser beam is scanned to the measurement object and the principle of triangulation is measured. The optical triangulation method is used to measure the change of the curved three-dimensional shape of the measurement object (ball of bump of the IC chip).

FIG. 3 illustrates the use of a laser beam on one side according to an optical triangulation method to measure the height of a ball of a bump of a ball grid array (BGA), a flip chip (FC), and a chip scale package (CSP) IC chip of a semiconductor inspection device. It is a system block diagram of a 3D image measuring apparatus.

Semiconductor inspection equipment directly controls high-performance lasers and optical phenomena that measure bumps of IC chips with high function, high speed, and high precision (µm, nm), and directs the laser beam through the lens tilted at an angle. Scanning into a ball of bumps, and obtaining a slit light with a CCD camera to measure the height of the measurement object (ball of the bump of the IC chip) from the geometric relationship.

However, a computer vision system for analyzing optical signals and a semiconductor inspection device (PCB inspection device) connected to a controller are three-dimensional measuring devices (optical triangulation) using a laser beam structured from a CCD camera, as shown in FIGS. 2 and 3. , The triangular measurement principle) has a problem that when the laser is scanned in one direction, it is difficult to measure the height of the ball of the bump of the invisible portion of the bump of the IC chip.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the problems of the prior art, and an object of the present invention is to use an optical triangulation method using a laser beam from a CCD camera in a computer vision system connected with a semiconductor inspection equipment (three-dimensional measurement inspection equipment) and an optical sensor controller. Bump ball of IC chip by moving IC chip by transfer device using semiconductor inspection equipment such as ball grid array (BGA), flip chip (FC) and chip scale package (CSP) using optical triangulation The laser is scanned from the two-way laser optical system simultaneously through the lens at a predetermined angle, and the left and right sides are measured by the CCD camera to measure the bump height of the IC chip according to the change in the height of the curved surface of the ball of the bump of the IC chip. PCB bump height measurement using a three-dimensional shape measurer using optical triangulation, which more accurately measures the bump height of the IC chip while dual scanning with the right laser To provide law.

In order to achieve the object of the present invention, PCB bump height measurement method using a three-dimensional shape measuring device using the optical triangulation method, (a) Ball Grid Array (BGA), Flip Chip (FC), Chip Scale Package (CSP), etc. Optional single laser optics or simultaneous ICs through lenses inclined at an angle from the left (L) or right (R) laser optics symmetrically configured in a computer vision system connected to the semiconductor PCB inspection equipment and the optical sensor controller Sequentially scanning the laser beam into the balls of the bumps of the chip and dual scanning the balls of the bumps of the IC chip; (b) When the IC chip is scanned from one of the left (L) or right (R) laser beams to the IC chip, the IC is used by the optical triangulation method according to the change in the length of the image formed by detecting reflected light with a CCD camera and an optical sensor. Measuring the bump height of the IC chip according to the change in the height of the curved surface of the bump of the chip; And (c) calculating the height of the bumps of each ball of the IC chip by arithmetic averaging the height values of the balls of the bumps of the two IC chips, measured simultaneously with the right (R) and left (L) laser beams. It includes a step.

As described above, the PCB bump height measurement method using the three-dimensional shape measuring instrument using the optical triangulation method, the optical triangulation method using a laser beam in a computer vision system connected with a semiconductor inspection equipment (three-dimensional measurement inspection equipment) and an optical sensor controller By using a BGA (Flip Grid), FC (Chip Chip) and CSP (Chip Scale Package) semiconductor inspection equipment, the IC chip is moved by a transfer device while the lens is angled from the CCD camera and the laser optics in two directions. Simultaneously scan the laser with the ball of the bump of the IC chip through and measure the bump height of the IC chip with the CCD camera according to the height change of the curved surface of the bump of the IC chip. The dual scanning of the characteristic information (the height of the ball of the bump) is effective in measuring the height of the invisible portion of the ball of the bump of the IC chip.

The three-dimensional shape measuring device technology using the optical triangulation method using two lasers of the semiconductor inspection equipment according to the present invention is capable of bi-directional measurement at the same time, the invisible part which is a problem of the optical sensor with high function and high accuracy of the existing semiconductor inspection maintenance Was measured more accurately.

The present invention uses a two-way laser optical system in the quality inspection process of the IC chip using optical measuring sensors of semiconductor inspection equipment such as ball grid array (BGA), flip chip (FC), chip scale package (CSP), etc. The bump height of the IC chip in the part not visible by the bidirectional measurement, and the BGA, FC, or CSP Ball to be measured selectively or simultaneously with the left (L) or right (R) laser beam depending on the relative position with the CCD camera. By scanning, by calculating the height of the balls of the bumps of the IC chip by the height arithmetic mean value of the balls of each bump of the IC chip during the simultaneous scanning, the height is measured on the invisible part of the balls of the bumps of the IC chip, By reducing the measurement error of the bump height of the IC chip and analyzing the defects, it is possible to more accurately determine the product defect of the IC chip.

1A is a view for explaining the principle of the conventional optical triangular method.
1B is a configuration diagram of a conventional probe type optical displacement sensor.
2 is a view for explaining the function of the three-dimensional shape measuring apparatus using the optical triangulation method.
Figure 3 is a three-dimensional image using a laser beam on one side according to the optical triangulation method to measure the height of the ball of the bump of the ball grid array (BGA) or flip chip (FC), chip scale package (CSP) IC chip of the semiconductor inspection equipment System diagram of the measuring device.
4 is a conceptual diagram of measuring the height of the bump of the IC chip of the BGA, FC, CSP ball using a three-dimensional measuring device of the semiconductor inspection equipment.
Fig. 5 is a view for explaining the principle of measuring the height of the ball of the bump of the IC chip of the optical triangulation method.
6 is a system configuration diagram of a three-dimensional image measuring apparatus using a laser beam in a dual scan according to the optical triangulation method for measuring the bump height of the IC chip of the BGA, FC, CSP ball of the semiconductor inspection equipment.
FIG. 7 is a view showing that the bump heights of the IC chips of the BGA, FC, and CSP balls of the semiconductor inspection equipment are selectively or simultaneously measured in the left and right directions.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a conceptual diagram of measuring the bump height of the IC chip of the BGA, FC, CSP ball using a three-dimensional measuring device of the semiconductor inspection equipment.

3D laser optical measurement sensor of semiconductor inspection equipment such as ball grid array (BGA), flip chip (FC) and chip scale package (CSP) and two symmetrical laser optical systems Selectively or simultaneously scanning the right (R) or left (L) laser while moving the IC chip, scanning the laser in one direction to the ball of the bump of the IC chip on the surface through the lens tilted at an angle. The laser light source reflected from the ball of the bump of the IC chip is received by a CCD (Charge Coupled Device) camera and an optical sensor, and the height of the ball of the bump of the IC chip is measured. Alternatively, when the laser is scanned from the right (R) laser optical system (21a, 21b) to the ball of the bump of the IC chip in one direction, there is an unmeasurable part where the laser is not scanned even if the reflected light is detected by the CCD camera. Ball of bump A measurement error of the height of occurred.

The three-dimensional shape measuring technology using optical triangulation using two laser optical system of the left (L) and the right (R) of the semiconductor inspection equipment according to the present invention is to measure simultaneously with the laser in two directions at the same time, We propose a method for measuring the height of the bumps of the bumps of the IC chip in the invisible part of the bumps of the bumps of the IC chip, which is a problem of the optical sensor with high function and precision of semiconductor inspection maintenance.

The present invention scans a laser beam into a ball of a bump of an IC chip placed on the surface of a semiconductor inspection device through a lens inclined at an angle from the left and right three-dimensional laser optical sensors of the semiconductor inspection equipment, The IC chip is moved by a transfer device, and the reflected light is detected by a CCD camera while performing dual scanning. The height of the bumps of the bumps of the IC chip is measured by the optical triangulation method, and the surface defects of the IC chip are inspected.

The three-dimensional optical measuring device measures only the arithmetic mean section of the bump of the IC chip and the height of the bump of the bump of the IC chip in the right laser measuring section when scanning the laser beam with the bump of the IC chip only when the right (R) laser is scanned. .

The three-dimensional optical measuring device measures only the arithmetic mean section of the bump of the IC chip and the height of the bump of the bump of the IC chip in the left laser measurement section when scanning the laser beam with the left (L) laser only by the bump of the IC chip. .

When the right (R) laser and the left (L) laser are simultaneously scanned with the bump of the IC chip, the laser beam is measured by moving the ball of the bump of the IC chip. The height of the ball of the bump of the IC chip is calculated by calculating the height measurement value of the ball of the bump of the two IC chips measured by the left or right laser.

(f는 렌즈의 초점 거리, f'은 렌즈의 환산 초점 거리), 카메라 렌즈로부터 CCD 센서까지의 거리가 r일때, CCD 센서의 일측점으로부터 광 수신점까지의 거리(삼각형의 길이) y'는 광삼각법에 의해 CCD 카메라를 통해 획득된 영상에서 추출한 높이 정보가 된다. 그러므로, 영상 삼각형의 높이 정보 y'와 측정 대상체 삼각형의 기준선에 대한 상대적이 높이 정보 z는 y'=

식이 설립한다. 3차원 형상 측정 장치는 측정 대상체(IC칩의 bump의 ball)의 높이 변위(z)가 렌즈로부터 측정 대상체까지 거리(f)에 비해 아주 작으면 z/f값이 아주 작으므로 무시할 정도로 작으며, 다음과 같은 근사식으로 실제 측정값인 높이 정보 y'를 구한다. 5 is a view for explaining the principle of measuring the height of the bump of the bump of the IC chip of the optical triangulation method. When scanning a laser beam from the left (L) laser optical system, the preset observation angle θ and magnification m =

(f is the focal length of the lens, f 'is the equivalent focal length of the lens), and when the distance from the camera lens to the CCD sensor is r, the distance (one triangle length) y' from one point of the CCD sensor to the light receiving point is Height information extracted from an image acquired by the CCD camera by the optical triangulation method. Therefore, the height information y 'of the image triangle and the height information z relative to the reference line of the measurement object triangle are y' =

Diet established. The 3D shape measuring apparatus is negligibly small because the z / f value is very small when the height displacement z of the measurement object (ball of the bump of the IC chip) is very small compared to the distance f from the lens to the measurement object. The height information y ', which is the actual measured value, is obtained by the following approximation.

y =

Here, n is the angle of the vertical line and the laser beam of the CCD camera, m is the magnification of the lens, θ means the observation angle of the camera of the CCD sensor with respect to the vertical line of the CCD camera.

식과 같이 CCD 카메라의 픽셀 간격에 대응하는 측정 대상체의 높이 값(측정 분해능)이 결정된다.If the pixel spacing of the CCD camera is Δy ', Δz =

As shown in the equation, the height value (measurement resolution) of the measurement object corresponding to the pixel interval of the CCD camera is determined.

The three-dimensional shape measuring apparatus of the semiconductor inspection equipment extracts three-dimensional shape information by acquiring an image of a laser beam measuring a change in a curved shape of a surface of a measurement object (a ball of a bump of an IC chip) with a CCD camera.

Recently, AOI (Automated Optical Inspection) two-dimensional inspection equipment is widely used among semiconductor inspection equipment and surface mount technology (SMT) inspection equipment, but PCB (Printed Circuit Board, PCB) for electronic products is used. The use of semiconductor chip inspection equipment such as BGA (Ball Grid Array), FC (Flip Chip), CSP (Chip Scale Package), etc. is used for integrated circuits and miniaturization of IC chips and substrates.

6 is a system configuration diagram of a three-dimensional image measuring apparatus using a laser beam in a dual scan according to the optical triangulation method for measuring the bump height of the pins of the IC chip of the BGA, FC, CSP ball of the semiconductor inspection equipment. .

PCB bump height measurement method using 3D shape measuring instrument using optical triangulation method (a) is connected to semiconductor PCB inspection equipment such as ball grid array (BGA), flip chip (FC), chip scale package (CSP) and optical sensor controller. Bump balls of the IC chip selectively or simultaneously through the lens tilted at an angle from the left (L) or right (R) laser optics symmetrically configured in a computer vision system, respectively. Sequentially scan laser beams, and dual scan the balls of the bumps of the IC chip while moving the IC chip by the transfer device of the measurement surface, and (b) either from the left (L) or right (R) laser optical system. When the laser beam is scanned on the bump of the IC chip, the height of the curved surface of the ball of the bump of the IC chip using the optical triangulation method according to the change in the length of the image formed by detecting the reflected light by the CCD camera and the optical sensor. The bump height of the IC chip is measured according to the change, and (c) the height of the ball of the bump of the IC chip when the laser beam is measured by one of the right (R) and left (L) laser optical systems. When the values are provided and measured simultaneously with the right (R) and the left (L) laser beams, the arithmetic average of the measured ball heights of the bumps of the two IC chips is used to determine the height of the bumps of each ball of the IC chip. Calculate.

Computer vision system connected to semiconductor PCB inspection equipment (3D measurement inspection equipment) such as ball grid array (BGA), flip chip (FC) and chip scale package (CSP) and optical sensor controller 11 Optionally, via a lens 22a, 22b inclined at an angle from the left (L) or right (R) laser optics 21a, 21b, which are symmetrically configured at 10). Changing the length of the image formed by scanning the laser beam with the ball of the bump of the chip and performing dual scanning of the balls of the bump of the IC chip while detecting reflected light with a CCD camera and an optical sensor. According to the optical triangle method, the left or right laser is scanned into the ball of the bump of the IC chip according to the change of the height of the curved surface of the bump of the IC chip, and the bump height of the IC chip is measured, respectively. In the common measuring section of the laser and the right (R) laser The arithmetic average of the ball heights of the bumps of the two IC chips measured by the L and R laser optical systems is used to calculate the ball height of each bump of the IC chip.

The semiconductor inspection equipment, which is a three-dimensional optical measuring device, is a high-speed CCD camera, a three-dimensional laser optical sensor, and optical for acquiring curved images of bumps of an IC chip scanned from two laser optical systems using optical triangulation and three-dimensional bump height measurement algorithms. It consists of a sensor controller.

The left laser optical system 21a, the left lens 22a, the right laser optical system 21b, and the right lens 22b are symmetrically configured, and are controlled by the computer vision system 10 and the optical sensor controller 11 According to this method, the left and / or right laser beams are selectively or simultaneously scanned into the bumps of the bumps of the IC chip, and the reflected light of the laser beam is detected by a CCD camera, respectively, to measure the height of the bumps of the bumps of the IC chip.

IC chips consist of many bump balls for soldering.

The 3D image measuring device of the semiconductor inspection equipment is a BGA, FC, or CSP ball that is to be measured using optical triangulation (three-dimensional measurement principle) under the control of the connected computer vision system 10 and the optical sensor controller 11. The laser beam can be selectively or simultaneously scanned according to the position 20 and the relative position, and the laser beam is scanned into the balls of the bumps of the IC chip in two directions from two mutually symmetrical laser optical systems. The height of the bump of the bump of the IC chip in the invisible portion of the more accurate measurement.

FIG. 7 is a view showing that the bump heights of the IC chips of the BGA, FC, and CSP balls of the semiconductor inspection equipment are selectively or simultaneously measured in the left and right directions.

In the semiconductor inspection equipment, when the IC chip is moved by the transfer device of the measurement surface, the laser beam is scanned from the left (L) laser optical system to the ball of the bump of the IC chip on the measurement surface. The resulting image shows the L4, L5, and L6 trajectories as shown in the figure (left).

When the IC chip is moved by the transfer device of the measurement surface of the semiconductor inspection equipment, the laser beam is scanned from the right (R) laser optical system to the ball of the bump of the IC chip on the measurement surface. The resulting image shows the R2, R3, and R4 trajectories, as shown in the figure (right).

When the IC chip is moved by the transfer device of the 3D laser optical measuring device, the right (R) laser beam has the height of the ball of the bump of the IC chip at ②, ③, and ④ having a predetermined distance distance from the center line. And the left (L) laser beam measures the height of the ball of the bump of the IC chip at ④, ⑤, ⑥ having a predetermined distance interval based on the center line.

In one embodiment, the 3D optical inspection apparatus turns on the right (R) laser optical system, turns off the left (L) laser optical system, and selectively converts the right (R) laser beam to the right laser measuring section (②, ③). The height of the bumps of the bumps of the IC chip is measured by scanning the bumps of the chip, and the right (R) and the left (L) lasers are simultaneously measured in the L and R laser simultaneous measurement section (④). 2) Turn on both the laser optical system and the left (L) laser optical system, and simultaneously scan the right (R) laser and the left (L) laser beam to the ball of the bump of the IC chip, and measure the height of the ball of the bump of the IC chip. The arithmetic mean of the bump height measurement values of the two IC chips is used to calculate the height of the bumps.In the left laser measurement section (5, 6), the right (R) laser optical system is turned off and the left (L) laser optical system is turned on. IC chip by scanning the left (L) laser beam selectively into the IC chip ball Measure the height of the ball bump.

Therefore, when measuring the height of the ball of the bump of the IC chip using a three-dimensional optical measurement sensor of semiconductor inspection equipment such as ball grid array (BGA), flip chip (FC), chip scale package (CSP), etc. By using the laser or the right (R) laser optical system, bi-directional measurement is possible, so that the height of the bump of the IC chip in the invisible portion can be measured more accurately. The laser beam is selectively or simultaneously scanned according to the IC, and the height of the balls of the bumps of each IC chip is calculated using an arithmetic mean value of the ball heights of the bumps of the two IC chips measured in two directions during the simultaneous measurement. The bump height of the IC chip in the invisible portion of the ball of the bump of the chip can be measured more accurately, the fine measurement error can be reduced, and the defect of the IC chip can be inspected more accurately.

As described above, the present invention has been described in detail through preferred embodiments, but the present invention is not limited thereto, and various changes and applications are apparent to those skilled in the art without departing from the technical spirit of the present invention. Accordingly, the true scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of the same should be construed as being included in the scope of the present invention.

10: computer vision system 11: optical sensor controller
20: CCD camera 21a, 21b: laser diode
22a, 22b: lens 23: bump of IC chip
30: measuring surface

Claims (9)

In the method of measuring the height of the IC chip bump of the PCB using a three-dimensional shape measuring device using the optical triangulation method,
(a) Left (L) or right symmetrically configured in a computer vision system connected with an optical sensor controller and semiconductor PCB inspection equipment including ball grid arrays (BGAs), flip chips (FCs), and chip scale packages (CSPs). (R) Scanning the laser beam into the balls of the bumps of the IC chip selectively or simultaneously through the lens inclined at a certain angle from the laser optical system, and moving the IC chip by the transfer device, Scanning the balls;
(b) When any one laser beam is scanned from the left (L) or right (R) laser optical system to the IC chip, the IC is used by the optical triangulation method according to the change in the length of the image formed by detecting reflected light by the optical sensor of the CCD camera. Measuring the height of each bump of the chip; And
(c) When measuring with either laser beam of the right (R) or left (L) laser optical system, the height value of the ball of the bump of the IC chip measured by the corresponding laser beam is provided, and the right (R) and the left (L) calculating the height of the ball of each bump of the IC chip by arithmetically averaging the height values of the balls of the bumps of the two IC chips, when measuring simultaneously with the laser beam;
The step (b)
In the right (R) laser measurement section, the right (R) laser optical system is turned on, the left (L) laser optical system is turned off, and the right (R) laser beam is scanned on the ball of the bump of the IC chip to bump the IC chip. Measure the height of the ball,
In the left (R) laser measurement section, the right (R) laser optical system is turned off, the left (L) laser optical system is turned on, and the left (L) laser beam is scanned on the ball of the bump of the IC chip to Measures the height of the bump's ball,
When the right (R) and the left (L) lasers are simultaneously measured, both the right (R) laser optical system and the left (L) laser optical system are turned on, and at the same time, the laser beam is scanned onto the bumps of the bumps of the IC chip. Measure the height of the bump of the IC chip bumps,
Scanning is performed by turning on the left laser, left and right lasers, and right laser optical systems in order for the scanning direction of the bumps.
In the step (b), when the laser beam is scanned in one direction from the left (L) or the right (R) laser optical system, the preset observation angle θ and magnification m of the camera =

(f is the focal length of the lens, f 'is the equivalent focal length of the lens), and when the distance from the camera lens to the CCD sensor is r, the distance (one triangle length) y' from one point of the CCD camera to the light receiving point is Compute the height information extracted from the image acquired by the CCD camera by the optical triangulation method,
The height information y 'and the height information Z relative to the reference line of the measurement object triangle are
y '=

Determined by
If the height displacement z of the measurement object (the ball of the bump of the IC chip) is smaller than the distance f from the lens to the measurement object, the z / f value is small. Therefore, the height information y ', which is the measured value, is obtained as follows.
y '=

(Where n is the angle of the vertical line of the CCD camera and the laser beam, m is the magnification of the lens, and θ is the angle of observation of the CCD camera relative to the vertical line of the CCD camera.)
If the pixel spacing of the CCD camera is Δy ',
Δz =

The height of the measurement object (measurement resolution) corresponding to the pixel spacing of the CCD camera, as shown in the equation is a PCB bump height measurement method using a three-dimensional shape measuring device using an optical triangle method. delete delete delete delete delete delete delete delete

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