Illumination light adjustment method for flux detection and detection apparatus using the same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHROMA ATE (SUZHOU) CO LTD
- Filing Date
- 2021-12-27
- Publication Date
- 2026-07-03
AI Technical Summary
Existing flux testing equipment has shortcomings in terms of accuracy and efficiency. In particular, it requires manual adjustment when dealing with different types of test objects, which leads to decreased testing efficiency and increased error.
An illumination adjustment method is used to collect and process image feature values under light intensity based on a pre-selected target range, using an image capturing device and a light source device, to evaluate and determine the optimal light intensity setting, thereby achieving adaptive illumination adjustment.
It improves the accuracy and efficiency of flux coating detection, and enables automatic light source adjustment of the detection equipment to adapt to different types of test objects.
Smart Images
Figure CN116399869B_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to an illumination light adjustment method and a testing device using the method; more specifically, this invention relates to an illumination light adjustment method for flux testing and a testing device using the method. [Background Technology]
[0002] Flux is a common auxiliary material in semiconductor manufacturing, used to ensure that the bonding between the solder ball bumps of electronic components (such as chips) and the substrate is completed correctly.
[0003] As semiconductor manufacturing processes become increasingly complex, advanced packaging processes demand ever higher precision, necessitating precise flux application onto semiconductor substrates. Over-application, under-application, or even the presence of particulate matter in the flux can easily lead to incorrect soldering results, resulting in decreased manufacturing yield or irreversible damage to electronic components (such as chips). Therefore, effective monitoring of flux application is essential.
[0004] Due to the wide variety of products, the characteristics of the test object itself and the corresponding flux thickness required may vary. For example, different types of substrates have different surface reflectivities. If the testing conditions are not configured appropriately, the testing equipment will produce errors in judging the flux coating condition. Therefore, it is necessary to optimize the settings of the testing equipment for each type of product.
[0005] However, this situation has created current challenges in inspection. First, the traditional method of manual visual adjustment is becoming increasingly inaccurate as semiconductor manufacturing processes become more complex, leading to increased errors. Second, different types of products require manual adjustments each time they are inspected, often resulting in decreased inspection efficiency. Therefore, the inspection of flux application needs to be carried out efficiently. [Summary of the Invention]
[0006] One of the objectives of this invention is to improve the detection efficiency of flux coating conditions.
[0007] Another objective of this invention is to improve the accuracy of flux coating detection.
[0008] To achieve the above and other objectives, this invention proposes an illumination light adjustment method for flux detection. This method obtains a light intensity setting configuration for a light source device based on a pre-selected target range. The target range includes a first target area coated with flux and a second target area without flux coating. The illumination light adjustment method includes: a data collection step, a data processing step, an evaluation step, and a determination step. The data collection step obtains a first feature value corresponding to the grayscale distribution in an image for the first target area under each illumination intensity, based on the grayscale distribution in the image, and obtains a second feature value corresponding to the grayscale distribution in an image for the second target area under each illumination intensity. The data processing step obtains a corresponding difference value based on the degree of difference between the first feature value and the second feature value corresponding to each illumination intensity. The multiple differences form a distribution relationship with their corresponding illumination intensities. The evaluation step determines, based on the distribution relationship, the illumination intensities corresponding to the multiple differences that satisfy a preset target difference value, and defines this as an evaluation result. The determination step determines that the evaluation result is the light intensity setting configuration.
[0009] In one embodiment of the present invention, the first feature value is the first image grayscale value corresponding to the first target area under each illumination light intensity, and the second feature value is the second image grayscale value corresponding to the second target area under each illumination light intensity. In the evaluation step, the illumination light intensity greater than the preset target difference value can be defined as the evaluation result.
[0010] In one embodiment of the present invention, the evaluation step further includes a pre-adjustment step. This step involves determining, among the plurality of first image grayscale values and the plurality of second image grayscale values, the illumination intensity corresponding to a non-desired threshold value, and defining it as a prohibited group not for use, wherein the evaluation result does not have any illumination intensity within the prohibited group.
[0011] In one embodiment of the present invention, the evaluation step is followed by an adjustment step. This step, based on the evaluation results and their corresponding grayscale differences, determines the updated evaluation result by identifying the illumination intensity corresponding to the largest increase in grayscale difference per unit increase in illumination intensity. The determination step uses the updated evaluation result to configure the illumination intensity.
[0012] In one embodiment of the present invention, the target range is one of the following four: a region within a chip bonding area, an edge region of the chip bonding area, a low-density bump region within the chip bonding area, and a high-density bump region within the chip bonding area.
[0013] In one embodiment of the present invention, the target range is one of a low-density bump region and a high-density bump region within the chip bonding area. The first characteristic value is the first bump spacing corresponding to the first target area under each illumination light intensity, and the second characteristic value is the second bump spacing corresponding to the second target area under each illumination light intensity. In the evaluation step, the illumination light intensity greater than the preset target difference is defined as a preliminary evaluation result, and the illumination light intensity corresponding to when the plurality of first bump spacings or the plurality of second bump spacings are greater than a preset spacing threshold value is removed from the preliminary evaluation result to further define it as the evaluation result. The bump spacing is the average spacing obtained in a grayscale image of the plurality of bumps within the target range under the corresponding illumination light intensity. The bump spacing corresponding to when the change in the plurality of first bump spacings or the plurality of second bump spacings with increasing illumination light intensity is greater than 20% is the preset spacing threshold value.
[0014] In one embodiment of the present invention, the evaluation step includes a pre-adjustment step, comprising an additional data collection step, an additional data processing step, and an additional adjustment step. The additional data collection step obtains a first bump count value for the first target area under each of the plurality of illumination intensities, and a second bump count value for the second target area under each of the plurality of illumination intensities, based on separate illumination under different illumination intensities. The additional data processing step obtains a bump count difference value based on the degree of difference between the first and second bump count values under each illumination intensity, and the plurality of bump count differences form a distribution relationship with their corresponding illumination intensities. The additional adjustment step determines, among the plurality of first bump count values and the plurality of second bump count values, the illumination intensities corresponding to conditions that satisfy the reduction of bump count, and defines this as a prohibited group not for use, wherein the evaluation result does not include any illumination intensities within the prohibited group.
[0015] In one embodiment of the present invention, the target range is one of the low-density bump region and the high-density bump region within the chip bonding area. The first characteristic value is the first bump spacing of the first target area under each illumination light intensity, and the second characteristic value is the second bump spacing of the second target area under each illumination light intensity. In the evaluation step, the difference corresponding to the gradient value corresponding to the plurality of differences as the illumination light intensity increases is the preset target difference value when the gradient value first exceeds a gradient threshold value.
[0016] In one embodiment of the present invention, in the data collection step, the plurality of illumination light intensities include the lowest to the highest illumination light intensities of the light source device.
[0017] In one embodiment of the present invention, the target range includes the first target area located on the first standard test object and the second target area located on the second standard test object. In the data collection step, the first standard test object and the second standard test object are irradiated one by one by the plurality of irradiation light intensities, and the corresponding first feature value and second feature value are obtained.
[0018] In one embodiment of the present invention, the target range includes a first target area and a second target area located on a standard test object. In the data collection step, the first target area and the second target area are irradiated one by one by the plurality of irradiation light intensities, and the corresponding first feature value and second feature value are obtained.
[0019] To achieve the above and other objectives, the present invention also proposes a detection device using the aforementioned illumination adjustment method, comprising: an image capturing device, a light source device, and a control device. The image capturing device is used to acquire an image of the target range. The light source device is used to provide illumination light of various intensities to the target range one by one. The control device is coupled to the image capturing device and the light source device, and the control device controls the light source device and the image capturing device according to the set target range to execute the illumination adjustment method, wherein the control device controls the intensity of the illumination light and obtains the plurality of first feature values and the plurality of second feature values from each image captured by the image capturing device.
[0020] In one embodiment of the present invention, the target range set by the control device is smaller than the surface area of the standard test object.
[0021] In one embodiment of the present invention, the control device is operated in at least one of a plurality of detection modes to perform the illumination adjustment method on the standard test object having a chip bonding region and a substrate. The plurality of detection modes include a glue overflow detection mode, a glue presence / absence detection mode, a low-density bump detection mode, and a high-density bump detection mode. Each detection mode has a corresponding target range to obtain a set value of the illumination intensity corresponding to each detection mode in the illumination adjustment method. In the glue overflow detection mode, the target range includes a plurality of first target areas and a plurality of second target areas, each first target area and each second target area being distributed at the edge of the chip bonding region. In the glue presence / absence detection mode, the target range includes a single first target area and a single second target area, the first target area and the second target area being distributed in the middle region of the chip bonding region and not covering the substrate. In the low-density bump detection mode, the target range includes at least one first target area and at least one second target area. The first target area and the second target area are located in the region of the chip bonding area with low-density bumps and do not cover the substrate. The control device is configured to use only the images at the bumps in the data acquisition step to obtain the plurality of first feature values and the plurality of second feature values. In the high-density bump detection mode, the target range includes at least one first target area and at least one second target area. The first target area and the second target area are located in the region of the chip bonding area with high-density bumps and do not cover the substrate. The control device is configured to use only the images at the bumps in the data acquisition step to obtain the plurality of first feature values and the plurality of second feature values.
[0022] Thus, based on the characteristic parameters of grayscale distribution in the image obtained under control conditions, and combined with the optimization processing of light source intensity, the illumination light adjustment method disclosed in this invention can achieve high efficiency and accurate determination of illumination light intensity for various types of test objects coated with flux. Furthermore, it enables the detection equipment using the method to have an adaptive illumination light adjustment function, achieving automatic adjustment of the detection light source. [Attached Image Description]
[0023] Figure 1 This is a schematic diagram of a detection device according to one embodiment of the present invention;
[0024] Figure 2 This is a schematic diagram of the object under test from a top-down perspective.
[0025] Figure 3 This is the illumination light adjustment method in the embodiments of the present invention;
[0026] Figure 4This is a schematic diagram showing the distribution relationship between image grayscale values and illumination light intensity;
[0027] Figure 5 This is a schematic diagram showing the relationship between the spacing of the protrusions and the intensity of the irradiated light.
[0028] Figure 6 for Figure 5 Add a schematic diagram showing the relationship between the gradient change in the spacing between the protrusions and the intensity of the irradiated light;
[0029] Figure 7 This is a schematic diagram showing the distribution relationship between the number of bumps and the intensity of the irradiated light.
[0030] Figure 8 This is a schematic diagram of the target range of a standard analyte under different detection modes.
Detailed Implementation Methods
[0031] To fully understand the purpose, features, and effects of the present invention, the present invention will now be described in detail with reference to the following specific embodiments and accompanying drawings:
[0032] In this application, the terms "a" or "an" are used to describe units, components, structures, devices, modules, systems, parts, or regions, etc. This is used merely for ease of explanation and to provide a general meaning for the scope of the invention. Therefore, unless it is obvious otherwise, this description should be understood to include one or at least one, and the singular also includes the plural.
[0033] In this application, the terms “comprising,” “including,” “having,” or any other similar terms are not limited to the elements listed in this application, but may include other elements not expressly listed but which are typically inherent in the unit, component, structure, device, module, system, part, or region.
[0034] In this application, the ordinal terms such as "first" or "second" are used to distinguish or refer to elements, structures, parts, or regions that are related to the same or similar entities, and do not necessarily imply a spatial order of these elements, structures, parts, or regions. It should be understood that in some cases or configurations, ordinal terms can be used interchangeably without affecting the implementation of the invention.
[0035] The testing equipment is equipped with a light source and an image capturing device. To ensure that the flux is applied correctly, the correct light intensity is required so that the flux can be effectively displayed in the test image. In addition, when using different types of test objects, different types of flux, and different coating thicknesses, the light intensity must also be adjusted accordingly to provide the test object with an appropriate intensity of illumination.
[0036] With the development of advanced packaging technologies, for example, multiple chips are integrated together and connected to the substrate through a redistribution layer (RDL) and solder ball bumps. In this case, the spacing of the solder ball bumps on the substrate is quite small (e.g., about 90 μm or less), which is different from the scale of ball grid array (BGA) packages. Therefore, the detection of flux coating on the substrate will require illumination light that can provide the correct illumination intensity.
[0037] The test object coated with flux can be a substrate, on which chip bonding areas are arranged for bonding chips via soldering. The chip bonding areas have multiple bumps that form electrical connections with coupling points on the bottom of the chip during the soldering process. The bottom of the chip may have coupling points with different densities that correspondingly bond with the chip bonding areas on the substrate. The chip bonding areas have bumps corresponding to these coupling points, thus forming bump regions with different densities on the substrate. These bump regions within the chip bonding areas are the areas where flux needs to be applied.
[0038] Please refer to Figure 1 This is a schematic diagram of a detection device according to an embodiment of the present invention. The detection device includes: an image capturing device 110, a light source device 120, and a control device 200. The control device 200 is coupled to the image capturing device 110 and the light source device 120. The control device 200 is used to control the light intensity output by the light source device 120 and to control the image capturing device 110 to capture an image of the object 300 under test, and to adjust the illumination light by processing the image. Figure 1 The example uses a bright field lighting configuration, but the illumination adjustment method described below can be applied to other bright field lighting configurations or dark field lighting configurations.
[0039] Please refer to Figure 2 This is a schematic diagram of the device under test (DUT) from a top-down view. The DUT 300 has a substrate 310 and at least one chip bonding region 320 defined on the substrate 310. The aforementioned bumps are arranged within the chip bonding region 320. Figure 2 The example shows a high-density bump region 321 with a denser bump distribution and a low-density bump region 322 with a looser bump distribution. Furthermore, the chip bonding area 320 defines the boundary where flux should be applied; flux exceeding this boundary is prone to overflow after chip bonding. Conversely, if flux does not reach this boundary, insufficient coating area will result, affecting the electrical properties after soldering.
[0040] Based on the distribution properties of the components on the test object 300, the illumination light adjustment method disclosed in this embodiment is performed according to a pre-selected target range, and the light intensity of the light source device can be set for the flux coating status within each target range. The illumination light adjustment method is based on a standard test object, and an optimal light intensity setting value for the light source device is generated correspondingly by observing the appearance of areas with and without flux coating in the image. Figure 2 As shown, in the detection mode, the pre-set target range includes a first target area 410 with flux applied and a second target area 420 without flux applied.
[0041] Figure 2 The example shows a test object 300 serving as a standard test object with two target areas for comparison. In other embodiments, two test objects 300 can be used (for example, distinguished as a first standard test object and a second standard test object). One test object has a first target area 410 coated with flux, and the other test object has a second target area 420 without flux coating. The target range can be a region within the chip bonding area, an edge region of the chip bonding area (covering both inside and outside the chip bonding area), a low-density bump region within the chip bonding area, and a high-density bump region within the chip bonding area. Each illumination light adjustment method corresponds to a target range, which can be selected from one of the aforementioned four types of regions. After the adjustment method is completed, the detection of the corresponding region can be performed using the determined light intensity setting configuration.
[0042] Please refer to Figure 3 This is an example of an illumination light adjustment method according to an embodiment of the present invention. The illumination light adjustment method includes the following steps:
[0043] Step S510, Data Collection Step. In this step, illumination is provided one by one with different illumination light intensities, and image data corresponding to the illuminated target area under each illumination light intensity is obtained. In each image data, the grayscale distribution can be converted into various feature values. These feature values are characteristics exhibited in the image grayscale values based on the correlation between the surface morphology of the illuminated object and the illumination light intensity. For example, the feature values can be: the grayscale values of the entire target area, the spacing values or size values obtained based on the surface morphology of the illuminated object, etc. The embodiments of the present invention are based on the target area corresponding to coated or uncoated flux, respectively, obtaining image data corresponding to each illumination light intensity, and obtaining corresponding feature values based on the grayscale distribution in the image data. In one embodiment, the plurality of illumination light intensities include the lowest to the highest illumination light intensities of the light source device 120, for example: 0~255.
[0044] Step S520, Data Processing Step. In this step, the difference between the first and second characteristic values corresponding to each illumination light intensity is obtained. Plotting these differences against the corresponding illumination light intensities establishes a distribution relationship, providing a basis for subsequent determination of the light intensity setting value.
[0045] Step S530, Evaluation Step. In this step, based on this distribution relationship and a pre-set target difference, the value of the illumination intensity corresponding to the current state of satisfying the preset target difference is determined, and this value is defined as an evaluation result.
[0046] Step S540, Determination Step. Based on the operation result of the aforementioned step S530, the control device 200 determines that the evaluation result is a light intensity setting configuration under the detection mode of the selected target range. The light intensity setting configuration is the light intensity state provided by the light source device 120 to the target area. For example, if the evaluation result corresponds to one or more optimal light intensity values, then the light source device 120 uses these light intensity values as the set configuration.
[0047] Next, please refer to Figure 4 This is a schematic diagram showing the distribution relationship between image grayscale values and illumination light intensity. Figure 4 This is an embodiment of adjusting the overall image grayscale value by summing the grayscale values of the selected target area. The first feature value refers to the first image grayscale value corresponding to the first target area under each illumination light intensity; the second feature value refers to the second image grayscale value corresponding to the second target area under each illumination light intensity.
[0048] exist Figure 4 In the implementation method, regarding step S520 and the data processing step, these grayscale differences can be plotted against the corresponding illumination light intensities to form a graph. Figure 4 The illustrated distribution line L3, that is, these grayscale differences and their corresponding illumination light intensities establish a distribution relationship that can be used to subsequently determine the light intensity setting value. Specifically, the grayscale value corresponding to each illumination light intensity of the first target area 410 coated with flux is the first image grayscale value, which can be used to determine the light intensity setting value. Figure 4 The first curve L1 is formed in the middle; the grayscale value corresponding to the second target area 420 without flux coating under each illumination intensity is the grayscale value of the second image, which can be obtained from the first curve. Figure 4 The second curve L2 is formed in the middle.
[0049] exist Figure 4In the implementation method, regarding the evaluation step S530, the intensity of the irradiated light corresponding to the current state that meets the preset target grayscale difference T1 is determined by using this distribution relationship and a preset target grayscale difference T1 (i.e., preset target difference), and this value is defined as the evaluation value. The preset target grayscale difference T1 is selected based on the stringency, and is generally defined as a value of 30±5%. It can be defined higher for more stringent conditions and lower for less stringent conditions.
[0050] exist Figure 4 In other embodiments, the evaluation value can be set as the lowest value of the illumination light intensity corresponding to the plurality of gray level differences when the preset target gray level difference T1 is met. That is, when multiple illumination light intensities correspond to gray level differences that all meet the condition of the preset target gray level difference T1, the lowest value of these illumination light intensities is used as the evaluation value.
[0051] exist Figure 4 In other embodiments, each numerical point can form a continuous curve (distribution relationship line L3) through general numerical analysis methods (such as interpolation), so that it can directly correspond to a value of illumination intensity when the preset target gray level difference T1 is met.
[0052] exist Figure 4 In other embodiments, evaluation step S530 may further include a pre-adjustment step. The pre-adjustment step determines, among the plurality of first image grayscale values and the plurality of second image grayscale values, the illumination intensity corresponding to a condition that satisfies (e.g., greater than or equal to) an undesired threshold value. These illumination intensities satisfying the undesired threshold value can be defined as a prohibited group. The existence of this prohibited group will ensure that the evaluation result generated by evaluation step S530 does not have any illumination intensity within the prohibited group.
[0053] For example, an undesirable threshold value can be set when the grayscale value has reached its maximum value (gmax). This threshold value can then be used to further exclude overexposure information, thereby improving image quality. Figure 4 When the first curve L1 reaches the maximum grayscale value (gmax), the corresponding illumination intensity value is T2. Illumination intensity values greater than or equal to T2 belong to the prohibited group, and the control device 200 will exclude values in the prohibited group in subsequent judgments.
[0054] To further explain, in evaluation step S530, the intensity of the illumination light that satisfies the preset target grayscale difference T1 (i.e., the preset target difference) is defined as a candidate group. For example... Figure 4For example, the intersection of the preset target grayscale difference T1 and the distribution relationship line L3 can correspond to a light intensity value. Other light intensity values greater than this value belong to the candidate group. When the light intensity value corresponding to the intersection of the preset target grayscale difference T1 and the distribution relationship line L3 is greater than the maximum light intensity value (imax, the maximum light intensity value, reaching the upper limit of the light source device 120), the value in the candidate group is zero (missing). With the addition of the pre-adjustment step, the light intensity values in the candidate group must be reduced by the light intensity values in the prohibited group. The remaining light intensity value after reduction is the evaluation result generated by the evaluation step S530.
[0055] exist Figure 4 In other embodiments, an adjustment step may be included after evaluation step S530 and before determination step S540. This adjustment step, based on the evaluation results of each illumination light intensity and its corresponding grayscale difference, determines the illumination light intensity corresponding to the largest increase in grayscale difference per unit increase in light intensity value as the updated evaluation result. The determination step uses the updated evaluation result as the light intensity setting configuration. This step is used to determine whether there is a better light intensity setting value. Based on each illumination light intensity and its corresponding grayscale difference value within the candidate group, the increase in grayscale difference value per unit increase in light intensity value is obtained, and the illumination light intensity corresponding to the largest of these is considered the updated evaluation result.
[0056] For example, if the illumination intensity A, the previous illumination intensity B, the grayscale difference A' corresponding to illumination intensity A, and the grayscale difference B' corresponding to the previous illumination intensity A' are (A / B / A' / B') in the candidate group: Group 1 (120 / 90 / 39 / 30), Group 2 (150 / 120 / 50 / 39), and Group 3 (180 / 150 / 57 / 50), then the grayscale difference that can be increased by each unit of illumination intensity is (A'-B') / (AB): Group 1 ((39-30) / (120-90)=0.3), Group 2 ((50-39) / (150-120)=0.36), and Group 3 ((57-50) / (180-150)=0.23). Thus, the second group (0.36) represents the candidate group that can increase the grayscale difference by a unit increase in light intensity, and its corresponding illumination intensity A (150) is the adjusted result. In other embodiments, when the largest increase in grayscale difference by a unit increase in light intensity is not singular but multiple, the largest illumination intensity is used as the updated evaluation result. For example, when both the first and second groups are (0.36), the illumination intensity corresponding to the second group is used as the updated evaluation result.
[0057] Next, please refer to Figure 5This is a schematic diagram showing the distribution relationship between the distance between the protrusions and the intensity of the irradiated light. Figure 5 This is another implementation method that adjusts the distance between bumps within a selected target range. In this implementation, the target range refers to either a low-density bump region or a high-density bump region within the chip bonding area. That is, each illumination adjustment method corresponds to a target range, which can be selected from one of the aforementioned two types of regions. After the adjustment method is completed, the detection of the corresponding region can be performed using the determined light intensity setting configuration.
[0058] In this embodiment, the first characteristic value is the first convex point spacing of the first target area under each illumination light intensity. The second characteristic value is the second convex point spacing of the second target area under each illumination light intensity.
[0059] The determination of the distance between convex points within a convex area can be achieved by evaluating the accumulated grayscale distribution of convex points in a single image (corresponding to a light intensity value) along an axis (e.g., along the long side or the wide side of the convex area) of each convex point in the image (convex points are reflective and appear as bright areas). By analyzing the accumulated grayscale distribution of each row or column of convex points along this axis (corresponding to actual position coordinates), the grayscale values can be converted into the positions of the convex points. Based on these positional relationships, the distance between rows or columns (convex point spacing) can be evaluated to obtain the average convex point spacing within the convex area (used as the convex point spacing in the data collection step). Identifying convex points from an image and estimating related parameters (such as convex point spacing, convex point diameter, and convex point length) are part of general image analysis and will not be elaborated upon here.
[0060] In the evaluation step S530 of this embodiment, the illumination light intensity greater than a preset target difference is defined as a preliminary evaluation result. The illumination light intensity corresponding to the distance between the plurality of first convex points or the distance between the plurality of second convex points being greater than a preset distance threshold value is removed from the preliminary evaluation result to further define it as the evaluation result. The preset target difference value can be defined based on the size and density of the convex points to ensure a discriminative rate between them. The preset distance threshold value can be based on the degree of change in the distance between the plurality of first convex points or the distance between the plurality of second convex points as the illumination light intensity increases. For example, under adjacent light intensities, when the difference between the next distance (e.g., corresponding to light intensity value 127) and the previous distance (e.g., corresponding to light intensity value 128) is greater than 20%, the corresponding convex point distance is defined as the preset distance threshold value.
[0061] like Figure 5For example, the average distance between the bumps in the first target area 410 coated with flux under each illumination intensity is the first bump spacing. Plotting the bump spacing d against the corresponding illumination intensity i can... Figure 5 The first curve L1 is formed in the middle. The average distance between the bumps in the second target area 420 without flux coating under each illumination intensity is the second bump spacing. Plotting the bump spacing d against the corresponding illumination intensity i... Figure 5 A second curve L2 is formed. The difference between the distance between the convex points corresponding to each illumination intensity i between the first curve L1 and the second curve L2 at each illumination intensity is plotted against the corresponding illumination intensity i to form a graph. Figure 5 The example distribution line L3, that is, these differences and their corresponding illumination light intensities establish a distribution relationship that can be used to subsequently determine the light intensity setting value. Through this distribution relationship and the preset target difference M1 (i.e., preset target difference), the value of the illumination light intensity corresponding to the current state that meets the preset target difference M1 is determined, and the evaluation result in the evaluation step S530 is further defined by obtaining the preset spacing threshold value M2.
[0062] The definition of the preset target difference M1 can be found in other embodiments. Figure 6 ,for Figure 5 Add a schematic diagram showing the distribution relationship between the gradient change in the spacing between the protrusions and the intensity of the irradiated light. In evaluation step S530, a gradient value (degree of change, in...) corresponding to the multiple differences (distribution line L3) as the intensity of the irradiated light increases can be used as a basis. Figure 6 The third curve (L4) is used to illustrate this. The difference corresponding to the first occurrence of the gradient value exceeding a gradient threshold value gr is defined as the preset target difference value M1'. The gradient threshold value gr is defined based on the degree of change; for example, a better gradient threshold value gr is defined when the degree of change is defined as 15-35%.
[0063] Further consideration of overexposure is possible. Figure 4 or Figure 5 In this implementation, the evaluation step S530 further includes a pre-adjustment step. This pre-adjustment step includes an additional data collection step, an additional data processing step, and an additional adjustment step. The pre-adjustment step performs the evaluation based on the number of bumps in the image.
[0064] For reference Figure 7 This is a schematic diagram illustrating the distribution relationship between the number of protrusions and the intensity of the irradiated light. The additional data collection step involves obtaining the number of first protrusions in the first target area under each of the multiple irradiated light intensities, based on separate irradiation. Figure 7The first curve L1 is presented in the middle. Also, the number of second convex points corresponding to each illumination light intensity in the second target area is obtained. Figure 7 The curve L2 is represented in the middle.
[0065] The additional data processing step obtains the corresponding bump number difference value based on the degree of difference between the first and second bump number values m under each illumination light intensity. Figure 7 The distribution relationship is represented by line L3. The difference in the number of the multiple bumps and their corresponding illumination light intensity i form a distribution relationship.
[0066] The additional adjustment step involves determining, among the plurality of first and second bump quantity values, the illumination intensity corresponding to the condition of reduced bump quantity (defined as the bump quantity threshold value M3). Furthermore, a prohibited group is defined for illumination intensity that meets this condition, ensuring that the evaluation result does not contain any illumination intensity within this prohibited group. That is, the illumination intensity value i corresponding to the first time the bump quantity difference (distribution line L3) meets the bump quantity threshold value M3 is used as a benchmark; illumination intensities greater than or equal to this illumination intensity value i are all classified into the prohibited group. This further facilitates the elimination of overexposure.
[0067] Next, please refer to Figure 8 This diagram illustrates the target range of a standard test object under different detection modes. These detection modes include an overflow detection mode, a glue presence / absence detection mode, a low-density bump detection mode, and a high-density bump detection mode. Each detection mode has a corresponding target range (pre-selected) so that the aforementioned illumination adjustment method can be used on the standard test object to allow the control device 200 to obtain the set value of the required illumination intensity for each detection mode. This allows the correct illumination intensity to be provided to each test object in the subsequent actual testing procedure to perform flux coating condition detection within the corresponding target range.
[0068] The user can pre-select the target range (corresponding to each detection mode) through the control device 200, or perform the aforementioned illumination adjustment method based on the target range (corresponding to each detection mode) stored in the control device 200. Furthermore, a standard test object can simultaneously have two target areas—coated and uncoated—for comparison, or two standard test objects can be used, each with a corresponding target area (serving as two target areas for comparison).
[0069] Figure 8This is a top view of one of the standard test objects (UTCs) in a test configuration using two standard UTCs. The target areas on both UTCs are identical for comparison. One UTC has correctly applied flux, while the other has no flux applied. The aforementioned target area includes a first target area on the first UTC with correctly applied flux (corresponding to each test mode) and a second target area on the second UTC without flux (corresponding to each test mode). This allows the control device 200 to perform adaptive illumination light adjustment to set the correct illumination light intensity for the corresponding test mode, achieving automatic adjustment of the test light source.
[0070] In the adhesive overflow detection mode, the target range includes multiple first target areas 410a and multiple second target areas (in... Figure 8 In one embodiment, the target area is located on another standard test object. The first target area 410a and the second target area are distributed at the edge of the chip bonding area 320. There is a narrow strip-shaped area without bumps between the edge of the chip bonding area 320 and the bump area. The flux application can be defined to not exceed the chip bonding area 320, thereby defining the target area at the edge of the chip bonding area 320.
[0071] In the presence or absence of adhesive detection mode, the target range includes a single first target area 410b and a single second target area (in... Figure 8 In one embodiment, the target area 410b is located on another standard test object. The first target area 410b and the second target area are distributed in the middle region of the chip bonding area 320 and do not cover the substrate 310.
[0072] In the low-density bump detection mode, the target range includes at least one first target region 410c and at least one second target region (in Figure 8 In one embodiment, the target area is located on another standard test object. The first target area 410c and the second target area are set in the chip bonding area 320, which has low-density bumps, and the target areas do not cover the substrate 310. The control device 200 is also used to obtain the first feature value and the second feature value by using only the image at the bump in the aforementioned data collection step S510.
[0073] In the high-density bump detection mode, the target range includes at least one first target region 410d and at least one second target region (in Figure 5 In one embodiment, the target area is located on another standard test object. The first target area 410d and the second target area are set in the area with high-density bumps in the chip bonding area 320, and the target areas do not cover the substrate 310. The control device 200 is also used to obtain the first feature value and the second feature value by using only the image at the bump in the aforementioned data collection step S510.
[0074] Since the bumps are made of metal, they have high reflectivity. The control device 200 can acquire image data of the bumps in the target area based on this, and then evaluate the grayscale value based solely on the image of the bumps. Furthermore, the evaluation based on the image of the bumps can also reveal dust spots, impurities, or other foreign objects in the target area in both low-density and high-density bump detection modes.
[0075] In summary, the illumination light adjustment method for flux testing can adaptively adjust the illumination light according to the different substrate surface colors, reflected light spectrum characteristics, and the differences in transmitted and reflected light spectrum characteristics of different types of flux. This achieves automatic adjustment of the detection light source, eliminating the need for manual visual adjustment of the illumination light intensity, which is prone to errors, and saving the cumbersome illumination light adjustment process. Therefore, the illumination light adjustment method for flux testing disclosed in this invention not only improves the detection efficiency of flux coating but also enhances the detection accuracy of flux coating.
[0076] Preferred embodiments of the present invention have been disclosed above. However, those skilled in the art should understand that the embodiments described herein are for illustrative purposes only and should not be construed as limiting the scope of the invention. It should be noted that all equivalent variations and substitutions to the embodiments should be understood to be covered within the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the claims.
[0077] [Attached image labels]
[0078] 110 Image Capture Device
[0079] 120 light source device
[0080] 200 control device
[0081] 300 test items
[0082] 310 substrate
[0083] 320 chip junction area
[0084] 321 high-density protrusion area
[0085] 322 Low-density bump area
[0086] 410 First Target Area
[0087] The first target area of 410a in the glue overflow detection mode
[0088] 410b first target area in glue presence / absence detection mode
[0089] The first target area of 410c in low-density bump detection mode
[0090] The first target area of 410d in high-density bump detection mode
[0091] 420 Second Target Area
[0092] d. Spacing between convex points (vertical axis)
[0093] i. Light intensity value (x-axis)
[0094] The maximum value of imax light intensity
[0095] g grayscale value (vertical axis)
[0096] gr gradient threshold
[0097] The maximum value of gmax grayscale value
[0098] L1 First Curve
[0099] L2 second curve
[0100] L3 distribution relationship line
[0101] L4 third curve
[0102] Number of bumps
[0103] M1 preset target difference
[0104] M1' Preset target difference
[0105] M2 preset spacing threshold value
[0106] M3 bump quantity threshold value
[0107] T1 Preset Target Gray Scale Difference
[0108] The intensity value of the irradiated light corresponding to the T2 undesired threshold value.
[0109] Steps S510-S540.
Claims
1. A method for adjusting illumination light for flux detection, comprising obtaining a light intensity setting configuration of a light source device based on a pre-selected target range, wherein the target range includes a first target area coated with flux and a second target area without flux coating, the illumination light adjustment method comprising: A data collection step involves obtaining a first feature value of the first target area based on the grayscale distribution in the image under each illumination intensity of multiple different illumination intensities, and obtaining a second feature value of the second target area based on the grayscale distribution in the image under each illumination intensity. A data processing step involves obtaining a corresponding difference value based on the degree of difference between the first feature value and the second feature value corresponding to each of the illumination light intensities, and a distribution relationship is formed between the multiple differences and their corresponding illumination light intensities. An evaluation step involves determining, based on the distribution relationship, the intensity of each irradiated light corresponding to a preset target difference among multiple differences, and defining it as an evaluation result. as well as A determination step is taken to determine that the evaluation result is the light intensity setting configuration.
2. The illumination light adjustment method as described in claim 1, wherein, The first feature value is the first image grayscale value corresponding to the first target area under each illumination light intensity, and the second feature value is the second image grayscale value corresponding to the second target area under each illumination light intensity. In the evaluation step, the illumination light intensity greater than the preset target difference value is defined as the evaluation result.
3. The illumination light adjustment method as described in claim 2, wherein, The evaluation step also includes: A pre-adjustment step determines the illumination intensity corresponding to a threshold value among multiple first image grayscale values and multiple second image grayscale values, and defines it as a prohibited group not for use, wherein the evaluation result does not have any illumination intensity within the prohibited group.
4. The illumination light adjustment method as described in claim 3, wherein, The evaluation step is followed by: One adjustment step involves determining, based on the evaluation results and their corresponding grayscale differences, the maximum increase in grayscale difference per unit increase in light intensity corresponding to the updated evaluation result. The determination step involves setting the light intensity configuration based on the updated evaluation results.
5. The illumination light adjustment method as described in claim 2, wherein, The target range is one of the following: a region within a chip bonding area, an edge region of the chip bonding area, a low-density bump region within the chip bonding area, and a high-density bump region within the chip bonding area.
6. The illumination light adjustment method as described in claim 1, wherein, The target range is one of a low-density bump region and a high-density bump region within a chip bonding area. The first characteristic value is the first bump spacing of the first target area at each illumination light intensity, and the second characteristic value is the second bump spacing of the second target area at each illumination light intensity. In the evaluation step, the illumination light intensity greater than the preset target difference is defined as an initial evaluation result. The illumination light intensities corresponding to multiple first bump spacings or multiple second bump spacings exceeding a preset spacing threshold value in the initial evaluation result are removed to further define the evaluation result. The first convex point spacing and the second convex point spacing are obtained based on the average spacing of multiple convex points within the target range in a grayscale image under corresponding illumination intensities. Wherein, when the change in the spacing between the first convex points or the spacing between the second convex points as the intensity of the irradiated light increases is greater than 20%, the corresponding convex point spacing is the preset spacing threshold value.
7. The illumination light adjustment method as described in claim 6, wherein, The evaluation steps include: A preliminary adjustment step, which includes an additional data collection step, an additional data processing step, and an additional adjustment step. The additional data collection step involves obtaining the number of first bumps in the first target area under each of the multiple illumination intensities, and the number of second bumps in the second target area under each illumination intensity, based on separate illumination under different light intensities. The additional data processing step obtains a corresponding bump number difference value based on the degree of difference between the first and second bump number values corresponding to each illumination light intensity. Multiple bump number differences form a distribution relationship with their corresponding illumination light intensities. The additional adjustment step involves determining the illumination intensity corresponding to the condition of reducing the number of protrusions among a plurality of first protrusion quantity values and a plurality of second protrusion quantity values, and defining it as a prohibited group not for use, wherein the evaluation result does not have any illumination intensity within the prohibited group.
8. The illumination light adjustment method as described in claim 1, wherein, The target range is one of a low-density bump region and a high-density bump region within a chip bonding area. The first characteristic value is the first bump spacing of the first target area under each illumination light intensity, and the second characteristic value is the second bump spacing of the second target area under each illumination light intensity. In the evaluation step, based on a gradient value corresponding to a plurality of differences as the illumination light intensity increases, the difference corresponding to the first occurrence of the gradient value being greater than a gradient threshold value is the preset target difference value.
9. The illumination light adjustment method as described in claim 1, wherein, In the data collection step, the plurality of illumination light intensities include the lowest to the highest illumination light intensities of the light source device.
10. The illumination light adjustment method according to any one of claims 1 to 9, wherein, The target range includes the first target area located on the first standard test object and the second target area located on the second standard test object. In the data collection step, the first standard test object and the second standard test object are irradiated one by one by the plurality of irradiation light intensities, and the corresponding first feature value and second feature value are obtained.
11. The illumination light adjustment method according to any one of claims 1 to 9, wherein, The target range includes the first target area and the second target area located on a standard test object. In the data collection step, the first target area and the second target area are irradiated by the plurality of irradiation light intensities one by one, and the corresponding first feature value and second feature value are obtained.
12. A detection device using the illumination adjustment method as described in any one of claims 1 to 9, comprising: An image capturing device for acquiring an image of the target area; A light source device is used to provide illumination light of various intensities to the target area one by one; as well as A control device is coupled to the image capturing device and the light source device. The control device controls the light source device and the image capturing device according to the set target range to execute the illumination light adjustment method. The control device controls the intensity of the illumination light and obtains a plurality of first feature values and a plurality of second feature values from each image captured by the image capturing device.
13. A detection device using the illumination adjustment method as described in claim 11, comprising: An image capturing device for acquiring an image of the target area; A light source device is used to provide illumination light of various intensities to the target area one by one; as well as A control device is coupled to the image capturing device and the light source device. The control device controls the light source device and the image capturing device according to a set target range to execute the illumination light adjustment method. The control device controls the intensity of the illumination light and obtains a plurality of first feature values and a plurality of second feature values from each image captured by the image capturing device. The target range set by the control device is smaller than the surface area of the standard test object.
14. A detection device using the illumination adjustment method as described in any one of claims 5 to 8, comprising: An image capturing device for acquiring an image of the target area; A light source device is used to provide illumination light of various intensities to the target area one by one; as well as A control device is coupled to the image capturing device and the light source device. The control device controls the light source device and the image capturing device according to a set target range to execute the illumination light adjustment method. The control device controls the intensity of the illumination light and obtains multiple first feature values and multiple second feature values from each image captured by the image capturing device. The target range includes the first target area located on the first standard test object and the second target area located on the second standard test object. In the data collection step, the first standard test object and the second standard test object are irradiated one by one by the plurality of illumination light intensities, and the corresponding first feature value and second feature value are obtained. The control device is operated in at least one of a plurality of detection modes to perform the illumination adjustment method on the first standard test object and the second standard test object having the chip bonding region and a substrate. The plurality of detection modes include an adhesive overflow detection mode, an adhesive presence / absence detection mode, a low-density bump detection mode, and a high-density bump detection mode. Each detection mode has a corresponding target range to obtain a set value of illumination intensity corresponding to each detection mode in the illumination adjustment method. In the adhesive overflow detection mode, the target range includes multiple first target areas and multiple second target areas, wherein each first target area and each second target area is distributed at the edge of the chip bonding area. In the adhesive-free detection mode, the target range includes a single first target area and a single second target area. The first target area and the second target area are located in the middle region of the chip bonding area and do not cover the substrate. In the low-density bump detection mode, the target range includes at least one first target area and at least one second target area. The first target area and the second target area are located in the region of the chip bonding area with low-density bumps and do not cover the substrate. The control device is also used in the data collection step to obtain multiple first feature values and multiple second feature values using only the images at the bumps. In the high-density bump detection mode, the target range includes at least one first target area and at least one second target area. The first target area and the second target area are set in the area of the chip bonding region with high-density bumps and do not cover the substrate. The control device is used to obtain multiple first feature values and multiple second feature values by using only the images at the bumps in the data collection step.
15. A detection device using the illumination adjustment method as described in any one of claims 5 to 8, comprising: An image capturing device for acquiring an image of the target area; A light source device is used to provide illumination light of various intensities to the target area one by one; as well as A control device is coupled to the image capturing device and the light source device. The control device controls the light source device and the image capturing device according to a set target range to execute the illumination light adjustment method. The control device controls the intensity of the illumination light and obtains multiple first feature values and multiple second feature values from each image captured by the image capturing device. The target range includes a first target area and a second target area located on a standard test object. In the data collection step, the first target area and the second target area are irradiated sequentially by the plurality of illumination light intensities, and the corresponding first feature value and second feature value are obtained. The control device is operated in at least one of a plurality of detection modes to perform the illumination adjustment method on the standard test object having the chip bonding area and a substrate. The plurality of detection modes include an adhesive overflow detection mode, an adhesive presence / absence detection mode, a low-density bump detection mode, and a high-density bump detection mode. Each of the detection modes has a corresponding target range to obtain a set value of the illumination intensity corresponding to each detection mode in the illumination adjustment method. In the adhesive overflow detection mode, the target range includes multiple first target areas and multiple second target areas, wherein each first target area and each second target area is distributed at the edge of the chip bonding area. In the adhesive-free detection mode, the target range includes a single first target area and a single second target area. The first target area and the second target area are located in the middle region of the chip bonding area and do not cover the substrate. In the low-density bump detection mode, the target range includes at least one first target area and at least one second target area. The first target area and the second target area are located in the region of the chip bonding area with low-density bumps and do not cover the substrate. The control device is also used in the data collection step to obtain multiple first feature values and multiple second feature values using only the images at the bumps. In the high-density bump detection mode, the target range includes at least one first target area and at least one second target area. The first target area and the second target area are set in the area of the chip bonding region with high-density bumps and do not cover the substrate. The control device is used to obtain multiple first feature values and multiple second feature values by using only the images at the bumps in the data collection step.