HK1077627B - Method and apparatus for measuring shape of bumps - Google Patents

Description

Apparatus and method for measuring convex shape

Technical Field

The present invention relates to a bump shape measuring apparatus and a method thereof for measuring a bump shape formed on a substrate at the time of manufacturing a multilayer printed substrate and at the time of mounting a semiconductor device, for example, and also relates to a method for manufacturing a multilayer printed substrate including bump shape management.

Background

In recent years, in the manufacture of printed boards, in order to achieve high precision and high density, a miniaturization and multi-layer technology is advancing at a large pace. In the interlayer connection of a multilayer printed board, a method of providing a hole in a connection portion by a drill, a laser, or the like and achieving conduction by plating has been mainstream. However, in recent years, a connection method using a bump has been adopted in accordance with the above-described increase in density and reduction in cost.

On the other hand, as a technique for determining whether or not a bump electrode formed in a semiconductor device or the like is good by image processing after the bump electrode is picked up by a camera, there are known: the techniques described in Japanese patent laid-open No. 11-26534, page 4, FIG. 4 (Prior Art 1), and Automation Vol.46 No.4(2001.4), pages 16-17, FIGS. 4 and 5 (Prior Art 2).

In prior art 1, it is described that: a light beam advancing in parallel with the main surface of the circuit member or an illumination light beam having a component parallel to the main surface is projected onto the bump electrode, a reflected light beam in a direction perpendicular to the main surface of the illumination light beam is incident on an imaging device, and detected image data obtained by the imaging device and reference image data stored in a storage device in advance are compared to determine whether the bump electrode is good or not based on the degree of coincidence.

In prior art 2, as a method for measuring the height of a bump from an image, there is described: the length of the shadow is detected by illuminating the projection with illumination from an oblique direction.

In order to manufacture a multilayer printed board, in the case of using a connection method using a bump, in order to ensure a high yield, immediately after the process of forming a bump on a lower printed board, it is necessary to confirm whether or not the position, height, bottom diameter, or other shape of the bump is designed on the entire surface of the board by a bump shape measuring device, and as a result, when conducting connection by the bump is performed by pressing the lower printed board and the upper printed board, it is necessary to eliminate the possibility of causing conduction failure.

On the other hand, products using such a multilayer printed board are often required to be mounted in a small size and at a high density, for example, in cellular phones, digital cameras, and the like, and in order to reduce the cost of the printed board itself by reducing the cost of the product, it is required that the bump shape measuring apparatus is also inexpensive and can measure the printed board with high reliability and high accuracy quickly and accurately.

However, in the above-described prior arts 1 and 2, these requirements are not sufficiently considered.

Disclosure of Invention

The present invention provides: a bump shape measuring device and method capable of quickly and accurately measuring the parameters of a bump required for reliable conduction connection with a simple configuration.

Further, the present invention provides: a bump shape measuring apparatus and a method thereof capable of presenting data on bumps required for controlling manufacturing conditions in a bump manufacturing apparatus.

In addition, it is still another object of the present invention to provide: a method for manufacturing a multilayer printed board, which can manufacture a multilayer printed board using a bump connection method with high reliability without conduction failure, high yield, and high yield.

That is, in the present invention, the following parts are provided to constitute the convex shape measuring apparatus, and:

a stage on which a substrate on which a plurality of projections as an object to be measured are arranged is placed and moved;

an illumination optical system for illuminating illumination light on a projection disposed on the substrate moved by the stage with an illumination optical axis having a low inclination angle with respect to a surface of the substrate;

a detection optical system for condensing reflected light from the bump illuminated by the illumination optical system with respect to the surface of the substrate by a detection optical axis having a higher inclination angle than the illumination light to detect an image signal of the bump;

an image processing unit for performing A/D conversion on the image signal of the bump detected by the detection optical system, calculating the contour of at least the tip portion and the bottom portion of the bump from the image signals of at least the tip portion and the bottom portion of the bump obtained from the A/D converted digital image signal of the bump, and calculating the geometrical feature quantity composed of at least the position and the height of the bump from the calculated contour of at least the tip portion and the bottom portion of the bump; and

and a main control unit for displaying information on the feature quantity concerning the geometry of the projection calculated by the image processing unit on a display device.

In addition, in the present invention, a convex shape measuring apparatus is configured by being provided with:

a stage on which a substrate on which a plurality of projections as an object to be measured are arranged is placed and moved;

an illumination optical system for illuminating illumination light on a projection disposed on the substrate moved by the stage with an illumination optical axis having a low inclination angle with respect to a surface of the substrate;

a detection optical system for detecting an image signal of the bump by condensing reflected light from the bump illuminated by the illumination optical system with a detection optical axis having a higher inclination angle than the illumination light with respect to the surface of the substrate;

an image processing unit for performing A/D conversion on the image signal of the bump detected by the detection optical system, calculating the contour of at least the tip and the bottom of the bump from the image signal of at least the tip and the bottom of the bump obtained from the A/D converted digital image signal of the bump, calculating the geometrical feature quantity composed of at least the position and the height of the bump from the calculated contour of at least the tip and the bottom of the bump, and determining whether the bump is good or not from the calculated geometrical feature quantity of the bump; and

a main control part for outputting the information of whether the projection judged by the image processing part is good or not.

In addition, the present invention provides a method for manufacturing a multilayer printed circuit board, comprising:

a bump manufacturing step of forming bumps on the lower printed board;

a projection shape measuring step of optically measuring a geometrical characteristic quantity composed of at least a position and a height of a projection formed in the projection manufacturing step to determine whether or not the projection is good;

an interlayer insulating film forming step of forming an interlayer insulating film by projecting a tip end portion of the bump on the printed board on which the lower layer of the good bump determined by the bump shape measuring step is formed; and

and a pressing step of applying pressure to the upper printed board after aligning the top surface of the projecting tip portion of the interlayer insulating film formed by the interlayer insulating film forming step, and electrically connecting the lower printed board and the upper printed board with the interlayer insulating film interposed therebetween by the projection.

According to the present invention, such effects are obtained: the parameters of the bump required for reliable conduction connection can be measured quickly and accurately with a simple structure.

Further, according to the present invention, a bump shape measuring apparatus capable of presenting data on bumps required for controlling manufacturing conditions in a bump manufacturing apparatus can be realized.

According to the present invention, such effects are obtained: by sequentially feeding back the measured height distribution and positional deviation of the bumps to the bump manufacturing apparatus, a multilayer printed board using a bump connection method can be manufactured with high reliability without conduction failure, high yield, and high throughput.

These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of illustrative embodiments thereof, as illustrated in the accompanying drawings.

Drawings

Fig. 1 is an explanatory view of an embodiment of a multilayer printed board manufacturing process using the bump connecting method according to the present invention.

Fig. 2 is a block diagram showing a projection shape measuring apparatus according to embodiment 1 of the present invention.

Fig. 3 is an explanatory diagram of an image signal detected by the detection optical system shown in fig. 2 and image processing in the image processing section.

Fig. 4(a) is a distribution diagram showing the geometric feature amount of the bumps by color, shade, shape, and the like, fig. 4(b) is a distribution diagram showing the geometric feature amount of the bumps by a three-dimensional vector, fig. 4(c) is a diagram showing a histogram in which the frequency (number) of the bumps with respect to the geometric feature amount is plotted, and fig. 4(d) is a diagram showing an auxiliary line added to the image signal of the detected bumps. Fig. 4(e) shows a detection image of a defective bump, and fig. 4(f) is a graph showing a change with time of a geometric feature of a bump.

Fig. 5 is an explanatory view of a case where the projection shape measuring apparatus according to the present invention is applied to a projection manufacturing apparatus and a CAD system.

Fig. 6 is a perspective view showing a 2 nd embodiment different from the 1 st embodiment of the detection optical system shown in fig. 2.

Fig. 7 is a plan view of the detection optical system shown in fig. 6 according to embodiment 2.

Fig. 8 is a perspective view showing embodiment 3, which is different from embodiments 1 and 2 of the illumination optical system.

Fig. 9 is a plan view of embodiment 3 of the illumination optical system shown in fig. 8.

Fig. 10 is a front view showing a detection optical system 2 according to embodiment 1 different from that shown in fig. 2.

Fig. 11(a) is a diagram showing a state in which the 1 st linear image sensor of the tip portion of the in-focus protrusion is imaged by the detection optical system shown in fig. 10, and fig. 11(b) is a diagram showing a state in which the 2 nd linear image sensor of the base portion of the in-focus protrusion is imaged by the detection optical system shown in fig. 10.

Fig. 12 is a front view showing embodiment 3, which is different from embodiments 1 and 2 of the detection optical system.

Fig. 13 is a diagram showing a state in which the 1 st linear image sensor at the tip end of the in-focus protrusion is imaged by the detection optical system shown in fig. 12 and the 2 nd linear image sensor at the base end of the in-focus protrusion is imaged.

Fig. 14 is a configuration diagram showing a 2 nd embodiment of a bulge shape measuring apparatus according to the present invention.

Fig. 15 is an explanatory view of the measurement of the projection shape and the measurement of the hole shape by the projection shape measuring apparatus shown in fig. 14.

Fig. 16 is an explanatory view of a manufacturing process of a multilayer printed board to be measured by the bump shape measuring apparatus shown in fig. 14.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In recent years, in order to achieve high precision and high density in printed circuit board manufacturing, a miniaturization and multi-layer technology has been advancing at a large pace. In particular, in the field of printed boards for notebook personal computers, PDAs, and cellular phones, high density packaging of components and high density and miniaturization of connections between wiring lines on a board and board layers have been carried out.

Accordingly, the connection method using the bump shown in fig. 1 is continuously applied with such high density and low cost. First, as shown in fig. 1(a), bumps 171 each having a pseudo-conical shape of copper, silver, or the like and a height of 200 μm are formed at points connected to the upper layer substrate on the printed substrate 170 forming the lower layer of the wiring. Of course, a base connected by a wiring is formed on the lower printed board 170 at the position where the projection 171 is formed. The projection 171 is formed by pasting particles of copper, silver, or the like with a solvent, printing a paste of silver, copper, or the like with screen printing or the like, and drying the paste. Alternatively, a paste of silver, copper, or the like may be applied to the lower printed circuit board 170, dried, and then subjected to a photo treatment and then etched.

At this stage, in order to ensure that the bumps 171 are electrically connected to the lower printed board 170 and the upper printed board 173 without short-circuiting between the adjacent bumps, that is, in order to eliminate the possibility of causing a conduction failure, it is necessary that at least the height of the bumps 171 in the pseudo-conical shape, the diameter of the base, the position in the XY direction, and the like are within a desired range. Therefore, in the projection shape measuring process 100 shown in fig. 1(b), in order to confirm whether or not the projections 171 are manufactured as designed at least in the height, the diameter of the base, the position in the XY direction, and the like over the entire surface of the substrate, the measurement is performed by the projection shape measuring apparatus according to the present invention, and the printed substrate 170 of the lower layer in which all projections are good OK is sent to the next process. On the other hand, the printed board 170 under NG having the defective bumps is fed back to the manufacturing conditions or design of screen printing or the like to improve the bumps manufactured thereafter into good products while discarding or correcting the defective bumps.

In the next step, as shown in fig. 1 (c), for example, an interlayer insulating film 172 such as a polyimide film is applied or laminated on the printed board 170 of the lower layer formed by the acceptable bump 171, and in the case of the laminated interlayer insulating film 172, a pressure is applied to open a hole so that the tip of the bump slightly protrudes from the interlayer insulating film 172. In this case, the thickness of the interlayer insulating film 172 is determined so that the tip of the bump slightly protrudes from the interlayer insulating film 172. When the interlayer insulating film 172 is applied, it is necessary to remove the resin film that adheres to the tip of the bump by etching or the like.

Next, as shown in fig. 1(d), the upper layer printed board 173 forming a base for connecting the wiring and the bump 171 is positioned in the XY direction with the lower layer printed board 170 and then attached to the tip portion of the bump.

Next, as shown in fig. 1(e), the upper printed circuit board 173 is aligned with the lower printed circuit board 170 and pressed to compress the bumps, thereby achieving conductive connection with the upper printed circuit board 173. Thus, the conductor connection can be realized by the good bump filled in the interlayer insulating film 172 between the lower printed substrate 170 and the upper printed substrate 173.

Subsequently, by repeating the steps shown in fig. 1(a) to 1(e), a miniaturized and multilayered multilayer printed circuit board can be manufactured with a high yield.

In the connection method by the bump, it is expected to achieve miniaturization and cost reduction as compared with the connection by the conventional plating for hole processing.

Next, an example of the projection shape measuring apparatus according to the present invention used in the projection shape measuring process 100 will be described.

Fig. 2 is a block diagram showing a projection shape measuring apparatus according to embodiment 1 of the present invention.

A printed board (substrate) 1 on which a plurality of projections 171 to be measured are formed is mounted by suction on a stage 2 movable in 3 directions of XYZ. The stage 2 holds the printed circuit board 1 by suction in such a manner as to eliminate the warp of the printed circuit board 1. Since the warpage is eliminated in this way and the height of the projection 171 is about 200 μm, the autofocus control system for the condenser lens 6 on the surface of the printed circuit board 1 does not have to be provided. Of course, by providing the autofocus control system, even if the thickness of the printed substrate 1 varies, an image of the same projection can be imaged on the image detection camera by the condenser lens 6. White light emitted from a light source 3 such as a halogen lamp is incident on an illumination lens system 4 via an optical fiber 5. The illumination optical system is composed of a light source 3, an optical fiber 5, and an illumination lens system 4.

In the case where a wiring pattern of copper or the like is formed on the printed board 1 and the projection 171 is a silver projection, the wavelength of the illumination light is preferably a short wavelength of 570nm (green) or less in order to obtain an image with a higher contrast than the background of the projection 171. Of course, the white light may be such that a large number of the wavelength components are contained. In short, the projections can be clearly seen against the background by using white light or light having a wavelength of 570nm (green) or less as illumination light. The illumination lens system 4 is, for example, a cylindrical lens which condenses a light flux 231 in a thin band shape (slit-shaped light flux) only in a direction perpendicular to the printed board 1, as shown in an enlarged view 220 of fig. 3. The illumination lens system 4 irradiates the printed circuit board 1 with illumination light 14 at a low angle α of 30 degrees or less. However, since the protrusions 171 are arranged on the printed circuit board 1 at a high density, if the illumination angle (the angle of the principal illumination ray with respect to the illumination optical axis) α is too low, the adjacent protrusions are affected. By thus irradiating the irradiation light 14 at the low angle α of 30 degrees or less, most of the reflection on the surface of the printed circuit board 1 including the base is regular reflection and is detected darkly without being incident on the condenser lens 6 as a background, and most of the scattered light on the surface of the projection 171 is incident on the condenser lens 6 as close to regular reflection light and is detected brightly. Since the intensity of scattering of reflection from the surface of the projection 171 is strong, the contrast with the printed board 1 as a background is high, and only the projection 171 can be clearly seen.

Most of the scattered light reflected from the surface of the projection 171 illuminated with the illumination light 14 enters the condenser lens 6, so that an image of the projection 171 brightly and clearly appearing on a dark background can be picked up by an image detection camera 7 composed of, for example, a CCD line sensor. The image detection camera 7 detects the image of the protrusion 171 by tilting the detection light axis at an angle β with respect to the protrusion 171, for example, at an angle β of 30 to 50 degrees, in order to capture an image including more height information of the protrusion 171. The detection optical axis corresponds to the optical axis of the condenser lens 6. The image detection camera 7 is, for example, a CCD line sensor, and detects an image signal of the image detection area 201 by continuously moving an imaging area (imaging field) 241 of the CCD line sensor in synchronization with scanning of the stage 2 indicated by an arrow as described in an enlarged view 220 of fig. 3 by the stage control unit 12 and the main control unit 13. At this time, the stage controller 12 inputs XYZ displacement measured by the displacement meter provided on the XYZ stage 2, and therefore, the main controller 13 is supplied with the displacement amount of the XYZ stage. Then, the image signal 8 detected by the image detection camera 7 is sent to the image processing unit 9.

The image processing unit 9 is composed of:

an A/D converter 9 for A/D converting the detected image signal 8; an image memory 92 for storing the a/D converted gradation value (gradation value) image signal F (x, y) 202; a clipping circuit 93 that clips a shading value signal [ P1(i, j) to Pn (i, j) ] (an image including only a convex region from the detection image) 204 for each of the bumps from the shading value image signal F (x, y)202 stored in the image memory 92 based on the bump arrangement design data; geometric data such as the height of the bump, the diameter of the bottom (base), and the center position thereof is calculated from the shading value signals [ P1(i, j) to Pn (i, j) ]204 clipped for each bump by the clipping circuit 93, whether or not the calculated bump geometric data is good is determined by comparing the calculated bump geometric data with a determination criterion, and the calculated bump geometric data and the result of the determination of whether or not the bump is good are output to the main image processing unit 94 of the main control unit 13.

The image data storage unit 11 cuts out and stores the shading value image signal Pk (i, j) of at least the defective bumps obtained from the main control unit 13 in the image memory 92 by the cutting circuit 93 for a long period of time. Therefore, the main control section 13 can display the gradation image signal Pk (i, j) for the defective protrusion on the display device 20 again according to the user's request. The main controller 13 may supply the shading value image signal Pk (i, j) for at least the defective bumps stored in the image data storage 11 to the bump manufacturing apparatus 111.

The cutting circuit 93 does not necessarily have to cut all of the bumps formed on the printed board, and may cut a typical bump. The representative projection, for example, as shown in fig. 4(a), is obtained by designation using a result of measurement in the past displayed on the display device 20. The representative bumps may be specified as a measurement recipe according to the manufacturing conditions.

The display device 20 displays various measurement results, a measurement recipe, measurement conditions, and the like.

The input device 21 inputs a measurement recipe concerning the object to be measured (for example, as shown in fig. 5, design data concerning the printed circuit board 1 including the type of the printed circuit board 1, which is obtained from the CAD system 110, design data 116 (corresponding to a printing pattern of screen printing, for example) arranged on the printed circuit board including the type of the bump, and bump manufacturing conditions 115 obtained from the bump manufacturing device 111), measurement conditions (for example, a criterion for determining whether the bump is good or not, or specification of a good bump and a bad bump), and a selection instruction for displaying or outputting the measurement result or a display or output mode.

The output device 22 also includes a network or the like fed back to the projection manufacturing device 111 and the CAD system 110 shown in fig. 5.

Next, the flow of the process of measuring the protrusion shape according to the present invention will be described with reference to fig. 3. Initially, the main control section 13 sets the image detection area 201 so that the area in which the bumps 171 to be measured are arranged can be detected efficiently, based on the bump arrangement data of the printed board input by the input device 21. The stage 2 holding the printed circuit board 1 by suction is moved in the XYZ-directions in accordance with a designated procedure under the control of the stage controller 2 in accordance with a command from the main controller 13 so that the imaging region 241 of the linear sensor of the image detection camera 7 scans the imaging detection region 201 to perform imaging. At the same time, the illumination lens system 4 irradiates the imaging region 241 with white light or light having a wavelength of 570nm or less as a slit-shaped light beam 231 at a low angle α of 30 degrees or less from the moving direction. As a result, the image signal obtained by the image detection camera 7 in synchronization with the stage scanning is converted into a digital image signal by the a/D converter 91 and stored as the image signal 202 in the image memory 92.

Next, the clipping circuit 93 extracts (clips) image data Pk (i, j)204 of only one bump by referring to the bump position CAD data (bump arrangement data) 203 obtained from the main control unit 13 from the image signal 202 stored in the image memory 92. The image data Pk (i, j)204 of only one protrusion is extracted (cut out) by the cutting-out circuit 93 in this way, so that the image processing in the main image processing unit 94 becomes easy, which is not necessarily required if the position, height and bottom diameter of the bottom of each protrusion are satisfactory.

Next, the main image processing unit 94 applies an image processing algorithm to the extracted one of the bump image data Pk (i, j) 204. Since the image detection camera 7 captures an image at an inclination angle β of 45 degrees in the moving direction, image data Pk (i, j)204 composed of bright portions with the background (the surface of the base and the printed substrate 1) as a dark portion is obtained from one projection. Therefore, the image data Pk (i, j)204 is subjected to 2-valued transformation by a certain threshold value to obtain convex edge (contour) coordinate data. In addition, the coordinate data of the edge (contour) of the bump can be obtained by differentiating the image data Pk (i, j)204 to obtain the coordinate of the peak.

Next, on the image data, for example, 2-order approximation curves or elliptic approximation curves 208 are calculated from the set (contour) 205 of edge points of the tip portion of the protrusion, and 2-order approximation curves or elliptic approximation curves 209, 210a, 210b are calculated from the sets (contour) 206, 207a, 207b of edge points of the bottom portion and the ridge line of the protrusion, whereby 2-dimensional geometric shapes when the protrusion is observed from an inclination angle β of 30 to 50 degrees are stably detected. By calculating the distance from the uppermost point of the calculated curve 208 to the lowermost point of the curve 209, the height H of the bump on the image data can be found. In addition, the bottom diameter (diameter of the base) D on the image data may be found. Further, by obtaining the midpoint coordinate of the intersection coordinates of the calculated curve 209 and the curves 210a and 210b, the position coordinate of the projection as the center position 212 of the base can be obtained.

When the actual height and bottom diameter of the projection are to be found, the height and bottom diameter may be multiplied by a correction coefficient based on the component of the detection angle β. As a method of finding the correction coefficient, calculation may be performed based on the result of actual measurement with a measuring tool for a representative bump and the height H and the bottom diameter D of the bump measured on the image data as described above.

As described above, in order to confirm that the bump 171 is surely conductively connected to the lower printed board 170 and the upper printed board 173 without short-circuiting between them, the bump 171 is shaped like a cone, and therefore, as a result of measurement by the bump shape measuring device, at least the height H and the bottom diameter D of the bump and the position 212 of the bump are obtained as necessary. By obtaining the height H of the bump, the bottom diameter (base diameter) D of the bump, and the bottom (base) position 212 of the bump, it is possible to determine whether or not the bump is good without causing the conduction failure. The height H of the bump and the bottom (base) position 212 of the bump are robust for the conductive connection to the base of the upper printed substrate 173. The bump bottom diameter D and bump bottom (base) location 212 are robust to make conductive connection with the base of the underlying printed substrate 170.

As the geometry of the projection, in addition, the shape (simulated cone angle) and volume of the tip portion are considered. The shape of the tip portion (simulated cone angle) can be obtained from the calculated 2-order approximation curve or elliptic approximation curve 208. The volume can be determined from the bottom diameter D, the height, and the shape of the tip (pseudo cone angle). However, in the case of forming the projection 171 as a screen printing, since it is obvious that there is a correlation between the height of the projection and the shape of the tip portion (pseudo-cone angle), it is generally sufficient to determine whether or not the projection is good by using the height information of the projection.

Next, an output mode of the display device 20 or the output device 22 for the result of the measurement of the protrusion shape performed by the main control unit 13 will be described. Fig. 4(a) shows the result of the measurement by the main controller 13 on the screen of the display device 20 as the distribution 120 of the height, the bottom diameter, the bottom position, and the like of the geometric feature of each bump on the printed circuit board. The distribution 120 changes the color, shade, or shape of each protrusion 121 in accordance with the amount of displacement from the design value. The main control unit 13 may display a projection determined to be defective by dividing the defects of the height, the bottom diameter, and the bottom position on the screen of the display device 20. By displaying the bumps determined to be defective for each defect type (height, bottom diameter, bottom position) in this manner, the cause of the defect can be easily found.

Fig. 4(b) shows the result of displaying the distribution 130 of the height, bottom diameter, bottom position, etc. of the geometric feature of each bump on the printed circuit board as the 3-dimensional vector 131 on the screen of the display device 20 as the result data measured by the main control unit 13. By expressing the measurement result in the distribution state on the printed substrate in this way, the state in the bump manufacturing process shown in fig. 1(a) can be easily grasped.

Thus, fig. 4(a) and (b) show the distribution 120, 130 of the geometric characteristic amount of the bumps on the printed substrate as information on the geometric characteristic amount (height, bottom diameter, bottom position, etc.) of the bumps.

Fig. 4(c) shows the result of displaying, as the result data measured by the main control unit 13, on the screen of the display device 20, a histogram 140 in which the height of the bump, the bottom diameter, the position, and the like are deviated from the design values on the horizontal axis and the frequency (number) is measured on the vertical axis, on the entire printed board or in each specific area. By displaying the histogram 140 in this manner, the number and distribution of the numbers in the criterion (design tolerance) 141 for determining whether or not the print substrate is good can be grasped for each specific area, and therefore, for example, re-evaluation of the setting of the criterion (design tolerance) as a measure recipe can be performed. In the case of histogram display, the distribution of the displacement amounts of the projections shown in (a) and (b) and the 3-dimensional vector may be displayed together with the histogram display. Thus, it is found that the dispersion difference is increased by the height of the projection, the diameter of the bottom, the position of the bottom, and the like.

As described above, fig. 4 c shows the frequency 140 of occurrence of bumps, which is information on the geometric features (height, bottom diameter, bottom position, etc.) of bumps, on the printed board.

If the screens shown in fig. 4(a), (b), and (c) described above are displayed for each bump making apparatus (for example, screen printer), the machine error of the bump making apparatus can be grasped.

Fig. 4 d shows a result of displaying the image on the screen of the display device 20 by, for example, designating a certain region by the input device 21 in a state where the screen shown in fig. 4 a is displayed on the display device 20, and adding the image of the bump itself stored in the image data storage 11 in the designated region and the bump of the bump edge (contour) calculated by the main image processing unit 94 from the image by the auxiliary line. Since the image of the projection with the supplemental line added to the edge is represented in this way, the actual state of the projection can be observed. The detected image of the projection is high in contrast with the background, and therefore, the supplementary line is not necessarily displayed.

Fig. 4(e) shows a result in which, for example, a defective protrusion is designated by the input device 21 in a state where the screen showing the defective protrusion shown in fig. 4(a) is displayed on the display device 20, and the main control unit 13 selects the designated defective protrusion image 150 from the images stored in the image data storage unit 11 and displays the selected defective protrusion image on the display device 20. By representing the defective bumps in this way, it is possible to confirm whether or not the measurement recipe such as whether or not the determination is good has been correctly made.

In fig. 4(f), the main control unit 13 calculates the change over time of the projection shape measurement result stored in the storage device 23 on a printed board basis or a batch basis, and displays the calculated change over time on the screen of the display device 20. That is, fig. 4(f) shows the change with time of the geometric characteristic amount of the bump as the information on the geometric characteristic amount (height, bottom diameter, bottom position, etc.) of the bump. As a result of measuring the shape of the projections for calculating the change with time, the average value of the height, the bottom diameter, the bottom position, etc. of the projections and the dispersion of the height, the bottom diameter, the bottom position, etc. of the projections are considered. By outputting the change over time in the shape of the projection as described above, it is possible to grasp that the change over time gradually increases due to, for example, clogging or the like in the case of screen printing and approaches within the criterion (design tolerance) for determination, and it is possible to issue a warning (alarm) in advance to take a countermeasure before a large number of defective projections occur. Further, by feeding back the change in the aging to the bump manufacturing process so as to correspond to the change in the manufacturing conditions of the bumps, it is possible to search for manufacturing conditions in which a failure has occurred.

The above-described configuration of the bump shape measuring apparatus 112 shown in fig. 5 can monitor the state of the manufacturing process of the bump. That is, when it is determined that a specific area on the printed circuit board 1 is insufficient in the bump height, bottom diameter, and other than the design tolerance (determination criterion) as the bump shape measurement result, the main control unit 13 outputs warning information such as an insufficient supply amount of the bump material to the specific area, and the output result 113 is supplied to the bump manufacturing apparatus 111 via the output device 22 such as a network, whereby the bump manufacturing apparatus 111 can issue a warning. In this way, the main controller 13 of the bump shape measuring apparatus 112 feeds back 113 the bump measurement results stored in the storage device 23 and the image data storage unit 11 to the manufacturing conditions (environment (temperature, humidity, air pressure), material (type, solvent concentration), and apparatus No.) in the bump manufacturing apparatus (for example, screen printer) 111, and controls the manufacturing conditions in the bump manufacturing apparatus 111, thereby enabling stable bump manufacturing.

In addition, when feedback to the bump manufacturing apparatus 111 cannot be improved, the bump shape measurement apparatus 112 can support design condition change such as more stable bump arrangement (density) by providing the bump shape measurement result 114 to the CAD system 110, and the CAD system 110. In this case, the bump shape measuring apparatus 112 can easily re-evaluate the setting of the design tolerance by grasping the number and distribution of the items to be measured (criterion) 141 based on the histogram of the items to be measured shown in fig. 4 (c). In addition, the bump manufacturing apparatus 111, when the occurrence of a defect cannot be improved even if the bump manufacturing conditions are controlled, finds out a design condition that does not cause a defect from the bump manufacturing conditions and feeds back the design condition to the CAD system 110, thereby performing a design change.

Next, an illumination optical system of a convex shape measuring apparatus according to embodiment 2 of the present invention will be described with reference to fig. 6 and 7. That is, in the 2 nd embodiment, the point different from the 1 st embodiment shown in fig. 2 is that: two illumination optical systems (illumination elements) 302 and 303 that illuminate from at least 2 directions of a plurality of directions are provided for the projection 171 on the printed substrate 1 as an object to be measured. The elevation angle α of the two illumination optical systems 302 and 303 is an angle lower than the angle β of the detection lens (condenser lens) 6, for example, about 10 degrees, and the angle γ between the two illuminations is an angle narrower than 180 degrees, for example, 150 degrees. It is to be noted that a plurality of two or more illumination optical systems may be used.

This example is illustrated in fig. 7. Fig. 7 is an oblique view of the illumination system of fig. 6 from above. The object projection 171 is illuminated from the left-right direction with two illumination systems 302 and 303. Thereby, the entire bump is illuminated and the elevation angle α is a lower angle than the detection optical system 6, and therefore, the detection lens 6 can clearly visualize and detect only a portion having height information of the bump with respect to the background. By thus illuminating from 2 directions, the ridge of the protrusion 171 having a pseudo-conical shape can be made significantly brighter than the background.

Next, embodiment 3 of an illumination optical system in the convex shape measuring apparatus according to the present invention will be described with reference to fig. 8 and 9. That is, embodiment 3 differs from embodiments 1 and 2 in that: a diffusion lens 502 is provided in front of the illumination element or the illumination optical system 501, and the illumination light from the illumination element or the illumination optical system 501 is expanded in the horizontal direction, so that the diffused light 503 is irradiated not only to the front of the projection 171 but also to the side. The elevation angle α of the illumination element or illumination optical system 501 is a lower angle than the detection lens 6, for example, 10 degrees. Fig. 9 is an oblique view of the illumination system of fig. 8 from above. The projection 171 to be measured is illuminated from the direction of the detection lens 6 by an illumination element or an illumination optical system 501 and a diffusion lens 502. Thereby, the entire bump is illuminated and the elevation angle α is a lower angle than the detection optical system 6, and therefore, the detection lens 6 can clearly visualize and detect only a portion having height information of the bump with respect to the background.

Next, embodiment 2 of the detection optical system in the convex shape measuring apparatus according to the present invention will be described with reference to fig. 10 and 11. That is, in the 2 nd embodiment, the point different from the 1 st embodiment shown in fig. 2 is that: an imaging lens 703 and a linear sensitive camera 704 (e.g., CCD linear image sensor) that will focus on the tip portion of the protrusion 171, and an imaging lens 705 and a linear sensitive camera 706 (e.g., CCD linear image sensor) that will focus on the bottom (base) of the protrusion 171 are provided. With such a configuration, the line-sensitive camera 704 captures a clear image of the tip portion of the bump 171, and the line-sensitive camera 706 captures a clear image of the bottom portion of the bump 171. That is, the projection 171 on the substrate 1 as the object to be measured is illuminated at the angle α described above by the embodiments 1 to 3 of the illumination optical system.

The detection lenses 701 and 6 are provided at the same elevation angle β as that of the detection optical system 1 of fig. 2. Reflected light 707 from the bump detected by the detection lens 701 is separated into 1 st light 708 and 2 nd light 709 by the light splitting system 702. The 1 st light 708 is imaged on the linear sensitive camera 704 with an imaging lens 703. In addition, similarly, the 2 nd light 709 is imaged on the linear sensitive camera 706 with the imaging lens 705.

Fig. 11(a) shows an example of image pickup in which the tip end of the protrusion 171 is brought into focus by the image forming lens 703 by the line-sensitive camera 704, and fig. 11(b) shows an example of image pickup in which the bottom of the protrusion 171 is brought into focus by the image forming lens 705 by the line-sensitive camera 706. A field of view 801, representing the field of view captured with the linear sensitive camera 704. Further, in order to image the convex tip portion by the line-sensitive camera 704 while scanning at the detection position 805 in the detectable region 803, the imaging lens 703 is adjusted so that the convex tip portion is in focus. Additionally, field of view 802, represents the field of view captured by the line sensitive camera 706. Further, in order for the line-sensitive camera 706 to take an image of the bottom of the bump while scanning at the detection position 806 in the detectable region 804, the imaging lens 705 is adjusted so that the bottom of the bump is in focus.

By detecting images at different focal planes in this way, even when the magnification of the detection lens 701(6) is increased to improve the measurement accuracy of the shape of the projection 171, image blur due to insufficient depth of focus can be prevented. Of course, even when the height of the projection 171 is increased, the projection tip portion and the projection bottom portion are imaged in a focused state, and therefore, the shape of the projection can be accurately detected with high resolution, and as a result, the accuracy of measuring the shape of the projection 171 can be improved.

Next, embodiment 3 of the detection optical system in the convex shape measuring apparatus according to the present invention will be described with reference to fig. 12 and 13. That is, in embodiment 3, the point different from embodiment 2 is that: an image of the tip portion of the protrusion 171 imaged by the imaging lens 901 is picked up by the line sensor 902, and an image of the bottom (base) of the protrusion 171 imaged by the imaging lens 901 is picked up by the line sensor 903. That is, the light receiving surface of the linear sensor 902 is set so that the tip portion of the projection is in focus, and the light receiving surface of the linear sensor 903 is set so that the bottom portion of the projection is in focus. Fig. 13 shows an example of image pickup by the linear transducers 902 and 903. The field of view 101, represents the field of view captured with the linear sensors 902 and 903. In the detectable region 102, an image of the via line 103 including the tip portion of the protrusion is formed by the line sensor 902, and an image of the via line 104 including the bottom portion of the protrusion is formed by the line sensor 903. In this way, since images are detected at different focal planes in the same manner as in embodiment 3, the same effects as in embodiment 2 can be obtained.

Next, embodiment 2 of the bulge shape measuring apparatus according to the present invention will be described with reference to fig. 14, 15, and 16. Embodiment 2 is the case of embodiment 1, in which an illumination optical system and a detection optical system capable of inspecting a through-hole (hole) formed in the printed board 10 are added. As one of the printed boards 10 to be measured, a through hole (hole) 180 formed by a drill or a laser in a region where no projection is formed is considered as shown in fig. 16(b) in the multilayer printed board shown in fig. 16(a) manufactured by the method shown in fig. 1. In addition to the printed board 10 as the object to be measured, a printed board in which a normal through hole is formed may be used.

That is, embodiment 2 is configured to be able to detect an image of the multilayer printed board 10 from above by adding, for example, to embodiment 1, an illumination optical system 17 for annularly illuminating the multilayer printed board 10 from above, a detection optical system including a detection lens 16 for condensing reflected light obtained from the multilayer printed board 10 from above, and a detection camera 15 for receiving an optical image of a pattern (through-hole) 180 of the multilayer printed board 10 obtained by the detection lens 16. With this configuration, the image processing unit 9 can measure the position and shape of the bump 171 formed on the printed board 1 using the image signal 8 detected by the line-sensitive cameras 7, 704, 706, 902, 903, and the image processing unit 9 can also measure the position and shape of the through-hole (hole) 180 processed in the multilayer printed board 10 using the image signal 8 obtained by the detection camera 15.

Next, an example of application of embodiment 2 will be described with reference to fig. 15. For the bump printed substrate 1 on which the object to be measured is mounted, the position and shape of the bump 171 are measured by the image processing section 9 and the main control section 13 based on the image signal 8 detected by the linear-sensitive cameras 7, 704, 706, 902, 903. The position and shape of the hole 180 of the multilayer printed board 10 after the hole is opened are measured by the image processing unit 9 and the main control unit 13 based on the image signal 8 obtained by the detection camera 15. The detection camera 15 detects a circular hole portion using an image signal of a dark portion and detects the periphery of the circular hole portion using an image signal of a bright portion, and therefore, in the main image processing unit 94, for example, an image signal stored in a hole vicinity region (which may be a region cut out for each hole) of the image memory 92 after a/D conversion is projected in the X-axis direction and the Y-axis direction (image signal is integrated), a diameter in the Y-axis direction is obtained by a distance between both edges in the Y-axis direction, a position coordinate in the Y-axis direction is obtained by obtaining a center position thereof, a diameter in the X-axis direction is obtained by a distance between both edges in the X-axis direction, and a position coordinate in the X-axis direction is obtained by obtaining a center position thereof.

The main control unit 13 compares the position information of the reference mark position measured by the measuring device (not shown) and stored in the storage device 23 with the reference mark position, thereby obtaining the correlation between the position 156 of the bump on the printed circuit board 1 as the measurement result 155 of the bump state and the position 158 of the hole on the multilayer printed circuit board 10 as the measurement result 157 of the hole state, and easily grasping the amount of displacement between the two positions on the multilayer printed circuit board 10. In addition, the method comprises the following steps: reference marks are formed on both the printed board 1 and the multilayer printed board 10.

In this way, in the hole 180 of the multilayer printed substrate 10 measured, as shown in fig. 16(c), a through-hole conductor 181 is thereafter formed by plating or the like. Therefore, when the conductor (the bump 171 or the through-hole conductor 181) is disposed at a high density, for example, the short circuit or the state close to the short circuit can be eliminated by checking the distance of the bump closest to the through-hole conductor.

As described above, according to the present embodiment, in the method and the production line for manufacturing the bumps on the printed substrate, the bump geometry distribution can be simply measured in a short time. Therefore, for example, by performing measurement after the formation of the bumps, and by sequentially feeding back the height distribution and the positional deviation of the bumps to the bump manufacturing apparatus, it is possible to stably perform apparatus management and production process management in the bump manufacturing process. Further, by comparing the bump measurement data with the design data, it is useful to improve the accuracy of manufacturing and simulation, and it is also possible to optimize the design change of the bump shape.

In addition, according to the present embodiment, when a multilayer printed board is manufactured by a bump-based connection method, a multilayer printed board having high reliability can be manufactured with high yield, and the yield can be improved, and the throughput of the entire process can be improved.

The bumps are described as being mounted on a printed circuit board, and the bumps include bumps mounted on a semiconductor wafer and a semiconductor chip, and ball bumps.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. This embodiment must be considered in all respects as illustrative and not restrictive, with all changes coming within the meaning and equivalency range of the appended claims being embraced therein.

Claims (22)

1. A convex shape measuring device is characterized in that,

comprises the following steps:

a stage on which a substrate on which a plurality of projections as an object to be measured are arranged is placed and moved;

an illumination optical system for illuminating a projection disposed on the substrate moved by the stage with an illumination optical axis having a low inclination angle with respect to a surface of the substrate;

a detection optical system for detecting an image signal of the bump by condensing reflected light from the bump illuminated by the illumination optical system with a detection optical axis having a higher inclination angle with respect to the surface of the substrate than the illumination light;

an image processing unit for performing A/D conversion on the image signal of the bump detected by the detection optical system, calculating the contour of at least the tip portion and the bottom portion of the bump from the image signal of at least the tip portion and the bottom portion of the bump obtained from the A/D converted digital image signal of the bump, and calculating the geometrical feature quantity composed of at least the position and the height of the bump from the calculated contour of at least the tip portion and the bottom portion of the bump; and

and a main control unit for displaying information on the feature quantity concerning the geometry of the projection calculated by the image processing unit on a display device.

2. The convex shape measuring apparatus according to claim 1,

the image processing unit further includes a diameter of a bottom of the projection as the calculated geometric feature of the projection.

3. The convex shape measuring apparatus according to claim 1,

the image processing unit further determines whether or not the projection is good based on the calculated geometric feature of the projection, and supplies the determination result to the main control unit.

4. The convex shape measuring apparatus according to claim 1,

the detection optical system includes:

a condenser lens for condensing the reflected light of each projection; and

and a linear image sensor for receiving the light reflected by the respective projections condensed by the condenser lens and converting the light into an image signal.

5. The convex shape measuring apparatus according to claim 1,

the illumination optical system is configured to be illuminated by the illumination light from a plurality of directions with respect to the projections.

6. The convex shape measuring apparatus according to claim 1,

the illumination optical system illuminates diffused illumination light as the illumination light.

7. A convex shape measuring device is characterized in that,

comprises the following steps:

a stage on which a substrate on which a plurality of projections as an object to be measured are arranged is placed and moved;

an illumination optical system for illuminating a projection disposed on the substrate moved by the stage with an illumination optical axis having a low inclination angle with respect to a surface of the substrate;

a detection optical system for detecting an image signal of the bump by condensing reflected light from the bump illuminated by the illumination optical system with a detection optical axis having a higher inclination angle with respect to the surface of the substrate than the illumination light;

an image processing unit for performing A/D conversion on the image signal of the bump detected by the detection optical system, calculating the contour of at least the tip and the bottom of the bump from the image signal of at least the tip and the bottom of the bump obtained from the A/D converted digital image signal of the bump, calculating the geometrical feature quantity composed of at least the position and the height of the bump from the contour of at least the tip and the bottom of the bump calculated, and determining whether the bump is good or not from the geometrical feature quantity of the bump calculated; and

a main control part for outputting the information of whether the projection judged by the image processing part is good or not.

8. The convex shape measuring apparatus according to claim 7,

the image processing unit further includes a diameter of a bottom of the projection as the calculated geometric feature of the projection.

9. The convex shape measuring apparatus according to claim 7,

the main control unit is configured to be capable of displaying information on the geometric feature of the projection calculated by the image processing unit on a display device.

10. The convex shape measuring apparatus according to claim 9,

the main control unit includes, as the information on the geometric feature of the bumps displayed on the display device, at least one of a distribution of the geometric feature of the bumps on the substrate, a bump occurrence frequency of the geometric feature of the bumps, and a change with time of the geometric feature of the bumps.

11. The convex shape measuring apparatus according to claim 7,

the image processing apparatus further includes an image data storage unit for storing the A/D converted image signal of the projection determined as at least the failure obtained by the image processing unit.

12. The convex shape measuring apparatus according to claim 7,

in the illumination optical system, the illumination light is white light or light having a wavelength of 570nm or less.

13. The convex shape measuring apparatus according to claim 7,

the detection optical system includes a condensing lens for condensing the reflected light of each projection; and

and a linear image sensor for receiving the light reflected by the respective projections condensed by the condenser lens and converting the light into an image signal.

14. The convex shape measuring apparatus according to claim 7,

the illumination optical system is configured to be illuminated by the illumination light from a plurality of directions with respect to the projections.

15. The convex shape measuring apparatus according to claim 7,

the illumination optical system illuminates diffused illumination light as the illumination light.

16. The convex shape measuring apparatus according to claim 13,

the line image sensor includes a 1 st line image sensor for receiving light while focusing on the tip end of each bump, and a 2 nd line image sensor for receiving light while focusing on the bottom of each bump.

17. The convex shape measuring apparatus according to claim 13,

the illumination optical system is configured to illuminate the protrusions in a narrow band shape corresponding to the light receiving region of the linear image sensor.

18. A method for measuring a convex shape is characterized in that,

comprises the following steps:

illuminating a protrusion disposed on the substrate from a 1 st inclination angle lower than a surface of the substrate;

obtaining an image signal of the bump by detecting reflected light reflected by the bump illuminated from a 1 st tilt angle direction in a 2 nd tilt angle direction higher than the 1 st tilt angle with respect to the surface of the substrate;

processing the image signal of the bump obtained by the detection and calculating a geometrical feature quantity including at least position and height information of the bump; then, after that,

and displaying information on the calculated feature quantity of the geometry of the projection on a screen.

19. The convex shape measuring method according to claim 18,

in the step of illuminating the substrate from the 1 st angle direction and the step of detecting the reflected light in the 2 nd inclination angle direction to obtain an image signal, the substrate is continuously moved in at least the 1 st direction.

20. The convex shape measuring method according to claim 18,

in the step of displaying on the screen, information on distribution of the height, bottom diameter, and position of the bump on the substrate is displayed on the screen as information on a geometric feature of the bump.

21. The convex shape measuring method according to claim 18,

in the step of displaying on the screen, as the information on the geometric feature of the projection, information on each of defects of the height, the bottom diameter, and the position of the projection is displayed on the screen.

22. The convex shape measuring method according to claim 18,

the geometric feature quantity calculated including at least the position and height information of the bump is a geometric feature quantity composed of at least the position and height of the bump calculated from the image signals of at least the tip and the bottom of the bump in the image signals of the bump obtained by the detection and at least the contour of the tip and the bottom of the bump calculated from the contour of at least the tip and the bottom of the bump calculated.