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CN110783224B - Assembling component carriers using offset information between structural features formed on opposite sides of a reference component - Google Patents

Assembling component carriers using offset information between structural features formed on opposite sides of a reference component Download PDF

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Publication number
CN110783224B
CN110783224B CN201910665765.XA CN201910665765A CN110783224B CN 110783224 B CN110783224 B CN 110783224B CN 201910665765 A CN201910665765 A CN 201910665765A CN 110783224 B CN110783224 B CN 110783224B
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camera
image
component
structural feature
optically
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CN201910665765.XA
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CN110783224A (en
Inventor
马尔科·特赖贝尔
马丁·普吕菲尔
卡尔·海因茨·贝施
马赛厄斯·赫德里奇
西尔维斯特·德梅尔
哈拉尔德·施坦兹尔
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ASMPT GmbH and Co KG
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ASM Assembly Systems GmbH and Co KG
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67092—Apparatus for mechanical treatment
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/70—Determining position or orientation of objects or cameras
    • G06T7/73—Determining position or orientation of objects or cameras using feature-based methods
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
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    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H01L22/20—Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
    • H01L22/24—Optical enhancement of defects or not directly visible states, e.g. selective electrolytic deposition, bubbles in liquids, light emission, colour change
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    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/544—Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps
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    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
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    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/83—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a layer connector
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K13/00—Apparatus or processes specially adapted for manufacturing or adjusting assemblages of electric components
    • H05K13/08—Monitoring manufacture of assemblages
    • H05K13/081—Integration of optical monitoring devices in assembly lines; Processes using optical monitoring devices specially adapted for controlling devices or machines in assembly lines
    • H05K13/0815—Controlling of component placement on the substrate during or after manufacturing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/30—Subject of image; Context of image processing
    • G06T2207/30108—Industrial image inspection
    • G06T2207/30141—Printed circuit board [PCB]
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    • H01L2223/00—Details relating to semiconductor or other solid state devices covered by the group H01L23/00
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    • H01L2223/54426—Marks applied to semiconductor devices or parts for alignment
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    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/18—High density interconnect [HDI] connectors; Manufacturing methods related thereto
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    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L2224/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • H01L2224/29001—Core members of the layer connector
    • H01L2224/29099—Material
    • H01L2224/291—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/29101—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of less than 400°C
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    • H01L2224/74—Apparatus for manufacturing arrangements for connecting or disconnecting semiconductor or solid-state bodies and for methods related thereto
    • H01L2224/75—Apparatus for connecting with bump connectors or layer connectors
    • H01L2224/757—Means for aligning
    • H01L2224/75701—Means for aligning in the lower part of the bonding apparatus, e.g. in the apparatus chuck
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    • H01L2224/75—Apparatus for connecting with bump connectors or layer connectors
    • H01L2224/757—Means for aligning
    • H01L2224/75702—Means for aligning in the upper part of the bonding apparatus, e.g. in the bonding head
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    • H01L2224/757—Means for aligning
    • H01L2224/75753—Means for optical alignment, e.g. sensors
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    • H01L2224/75—Apparatus for connecting with bump connectors or layer connectors
    • H01L2224/759—Means for monitoring the connection process
    • H01L2224/75901—Means for monitoring the connection process using a computer, e.g. fully- or semi-automatic bonding
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    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/83—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a layer connector
    • H01L2224/8312—Aligning
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    • H01L2224/83121—Active alignment, i.e. by apparatus steering, e.g. optical alignment using marks or sensors
    • H01L2224/83132—Active alignment, i.e. by apparatus steering, e.g. optical alignment using marks or sensors using marks formed outside the semiconductor or solid-state body, i.e. "off-chip"
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    • H01L24/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L24/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L24/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector

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Abstract

A method and an assembly machine (100) for assembling a component carrier (180) with electronic components (190, 490 c) are described. The method comprises the following steps: (a) Acquiring a first image of a first side of a first element on which a first structural feature (296 a, 496 a) is identifiable; (b) Optically capturing a second image of a second side of the first element (190, 490 c) at which a second structural feature (294, 296b, 496 b) is identifiable, wherein the first side and the second side are opposite one another; (c) Determining a spatial offset (c 1) between the first structural feature (296 a, 496 a) and the second structural feature (294, 296b, 496 b); (d) Optically capturing an image of one side of the second element (190, 490 c); (e) Determining a spatial position of the second element (190, 490 c) based on the acquired image of one side of the second element (190, 490 c); and (f) assembling the second element (190, 490 c) to the element carrier (180) based on the determined spatial position of the second element (190, 490 c) and the determined spatial offset (c 1).

Description

Assembling component carriers using offset information between structural features formed on opposite sides of a reference component
Technical Field
The present invention relates to a method and apparatus for assembling component carriers with electronic components, the opposite sides of which are optically measured before the electronic components are assembled onto the component carriers.
Background
In the manufacture of electronic components with housings, a housing-free (semiconductor) chip (so-called "bare chip") is mounted on a component carrier or carrier. In the category of so-called "embedded wafer level packages" (eWLP), one or more chips of each Package (Package) are placed with the active side facing upwards on an adhesive film on a carrier. Subsequently, a plurality of mounted chips are cast with the aid of a plastic material, which is then followed by the housing. The entire cast product is then baked under high pressure and then released from the carrier or adhesive film. In a subsequent process step, the chips are contacted, if necessary also electrically connected, and solder balls are placed which serve as electrical connection contacts. At the end, the entire further processed cast product is sawn into individual elements or otherwise crushed.
Intuitively, eWLP is a housing design for an integrated circuit, in which the electrical connection contacts are produced on a wafer made of chips and casting material. All the required processing steps are also performed here in order to form the shell on the artificial wafer. This allows for the manufacture of very small and flat housings with excellent electrical and thermal properties at particularly low manufacturing costs, relative to conventional packaging techniques (where so-called "wire bonding" is applied). With this technique, a device used as, for example, a ball grid array package (BGA) can be manufactured.
Within the scope of the eWLP process, chips which have not yet been provided with a housing are typically handled by means of an assembly machine in comparison with the known surface mount technology (correction). The assembly machine has an assembly head by means of which the chips are mounted or positioned at predefined assembly positions on the respective carriers. In this case, the position accuracy of the assembly is particularly high.
For high-precision assembly, for example for eWLP processes, it is generally necessary to assemble the components to be assembled (without a housing) on the basis of the structure of the upper side of the component carrier. However, with conventional component cameras of automated assembly machines, only the structure of the underside of the component can be measured. By making additional measurements on the upper side using an (additional) camera, the offset or spatial offset between the structure on the upper side and the structure on the lower side can be determined. Such additional measurements of the components slow down the assembly process. This may be of little importance in assembly operations where only a few components have to be assembled to the component carrier with such a high degree of precision. However, when producing electronic components with a housing by means of "eWLP", the component carrier is equipped with a large number of components, for example 100000 components, which leads to a significant reduction in efficiency even with the slightest "slowing down" in the assembly process.
Disclosure of Invention
It is an object of the present invention to provide a method and a device for highly accurate and time-efficient assembly of component carriers with components, wherein information about the components present on different sides of the structural features is taken into account.
The solution according to the invention for achieving the above object is the technical features of the independent claims. Advantageous embodiments of the invention are found in the dependent claims.
According to a first aspect of the invention, a method for assembling a component carrier with an electronic component is described. The method comprises the following steps: (a) In particular, a first image of a first side of the first element is optically recorded by means of a first camera, on which first side a first structural feature of the first element can be detected; (b) In particular, a second image of a second side of the first element is optically recorded by means of a second camera, on which second side a second structural feature of the first element can be detected, wherein the first side and the second side are opposite to each other; (c) Determining a spatial offset between the first structural feature and the second structural feature; (d) In particular by means of a first camera and a second camera, an image of one side of the second element is optically recorded; (e) Determining a spatial position of the second element based on the acquired image of one side of the second element; and (f) assembling the second component onto the component carrier based on the determined spatial position of the second component and the determined spatial offset between the first and second structural features of the first component.
The method is based on the following recognition: by using the first element as a reference element and only for which the spatial offset between the optically detectable structure on the upper side of the reference element and the optically detectable structure on the lower side of the reference element is determined, a highly accurate assembly of a plurality of elements or a series of elements can be achieved in an efficient or fast manner. Such spatially offset measurements should be performed with particularly high accuracy, and the time factors of such measurements may play a secondary role. Thereafter, the second element is optically inspected with only one camera on only one side of the second element, and during subsequent assembly of the second element, not only the image information of the image of the second element taken from only one side is taken into account, but also the spatial offset measured for the first reference element. In the method described, it is assumed that at least for a certain number of components (preferably lots, or preferably wafers in the case of semiconductor chips) the possible spatial offset between the upper side and the lower side is at least approximately the same.
The term "electronic component" or "component" is understood in the sense of the present invention as all mountable components that can be mounted or assembled to a component carrier. The term "element" may include elements with housings, in particular elements without housings or chips. These include bipolar or multipole SMT components or other highly integrated planar, circular or differently shaped components such as ball grid arrays, bare chips, flip chips or individual parts such as ballasts. Semiconductor chips of semiconductor wafers are further processed into finished components, in particular after structuring and dicing the wafers.
The term "component carrier" is understood in the context of the present invention to mean any kind of mountable medium, in particular a substrate or a printed circuit board. The mountable media, in particular the printed circuit board, may be rigid or flexible. It may also have at least one first rigid region and at least one flexible region. The assemblable medium may also be a temporary carrier on which the chips, which have not yet been provided with a housing, are mounted for the purpose of manufacturing the component, for example by means of a so-called "embedded wafer level packaging (eWLP)" process. Such a temporary carrier may be an adhesive foil which is stretched over the frame structure in a known manner. The adhesive foil may be an exothermic foil (so-called thermo release foil) so that the adhered chip can be easily peeled off from the (previous) adhesive foil by using thermal energy.
The concept "assembly" is understood in the present invention as the attachment of electronic components to a component carrier in any way. In this regard, the attachment may be permanent, for example, in the case of circuit boards assembled by means of subsequent melting and solidification of the solder. The attachment may also be temporary, for example in the case of assembling a tensioned carrier foil for manufacturing an artificial wafer for producing packaged semiconductor elements.
In a preferred embodiment of the invention, the first element and the second element used as references are of the same type. It is thus possible to assume with a particularly high degree of accuracy that the spatial offset measured for the first element is equal to the spatial offset between the corresponding structures of the (unmeasured) second element.
The determined offset relates in particular to an offset in a plane oriented parallel to both sides of the first element. In the case of a cuboid-shaped element, the two sides are preferably two larger main sides, wherein the electrical connection contacts of the element are formed on at least one of the two main sides.
Depending on the specific application, the structural features may for example comprise electrical connection contacts of the relevant element, edges of the housing or package of the relevant element, edges of the (semiconductor) chip without the housing element, the (small) chip with the transparent packaged (LED) element, etc.
The spatial offset (also referred to herein as offset) may be a real-existing offset and/or a virtual offset. For example, in the case of semiconductor chips, during the fabrication of the chips on the wafer plane, a true bias may occur due to inaccuracies in the different lithography steps. For example, if the optical axes of the two cameras are not fully (parallel) oriented with respect to each other, a virtual offset may occur. Thus, although in reality there is no spatial offset, for highly accurate assembly, virtual offset must also be considered, which needs to be properly position compensated during assembly of the second element.
According to an embodiment of the invention, the method further comprises: (a) Determining a spatial position of the first element based on (i) the acquired first image of the first side of the first element and/or (ii) the acquired second image of the second side of the first element; and (b) assembling the first component onto the component carrier based on the determined spatial position of the first component and the determined spatial offset between the first and second structural features of the first component.
In this embodiment, the first (reference) element for determining the spatial offset or deviation is the actual element, which then becomes part of the resulting assembly of the assembled component carrier. As a result, neither a separate reference element nor a removal of an element used as a reference after determining the offset from the placement process is required. This has the advantage that the method can be repeated in a simple manner from time to time on the basis of a long-term assembly of a plurality of components on the component carrier, so that the spatial offset values can be updated repeatedly. As a result, component inaccuracies can be at least substantially eliminated, based on the spatial offset variations between individual components within a series of components (e.g., due to production conditions that are not entirely continuous over time). Undesired thermal drifts in the components of the assembly machine used to perform or in which the method is performed can also be at least partially eliminated.
According to another embodiment of the invention, the spatial position of the second element relates to an optically detectable structure (on the relevant side of the second element).
The optically detectable structure may be any functional feature of the second element that is characteristic and/or necessary for operation of the second element. Depending on the type of functional feature, it may (a) be located on a first side and taken up by the first camera, or (b) be located on an opposite second side of the second element and taken up by the second camera accordingly.
According to another embodiment of the invention, the optically detectable structure comprises an electrical connection contact of the second element.
An advantage of assembling the second component based on the location of the electrical connection contacts (rather than based on other optically detectable structures that are not important or only of minor importance for the function of the second component) is that the second component can always be reliably electrically contacted to a component carrier, such as a printed circuit board or a semiconductor substrate. The same applies to the fact that the participating electrical connection surfaces (connection contacts and/or connection pads on the component carrier) are very small and/or very close to each other in space. This aspect is of increasing importance as electronic components are miniaturized.
According to another embodiment of the invention, the second element is a light emitting semiconductor element and the optically detectable structure comprises a light emitting surface of the semiconductor element.
Assembling the light emitting semiconductor elements based on the precise position of the light emitting surface may be particularly advantageous in optoelectronic applications, as the light source of the light emitting semiconductor elements (and not just the electrical connection contacts) is thereby precisely positioned. As a result, the beam path can be "laid" or formed on the component carrier with a high degree of accuracy. In short, it is always advantageous to assemble the light emitting semiconductor element with respect to the light emitting surface when the "optical" precision requirement for the position of the light source is higher than the "electrical" precision requirement for the accurate electrical contact.
The light emitting semiconductor element may be a Light Emitting Diode (LED) or a laser diode, such as a Vertical Cavity Surface Emitting Laser (VCSEL).
According to another embodiment of the invention, the first structural feature comprises an edge of the first side of the first element. Alternatively, the second structural feature comprises an edge of the second side of the first element. Furthermore, the acquired image of one side of the second element shows the edge of the second element. This has the advantage that the spatial position of the second element is determined on the basis of a clearly and clearly identifiable structure, so that this determination can be performed with a high degree of accuracy and reliability.
Another significant advantage of this embodiment in certain applications, especially in the assembly of semiconductor chips taken directly from a wafer, will be shown, as when the element is not a perfect cuboid shape, but has side surfaces that are inclined or slanted with respect to the base plane. Such inclined side surfaces may be formed, for example, by a non-optimal mechanical sawing process for dicing the semiconductor chips or a sawing process performed by means of a laser beam. By determining the spatial offset described in the present invention, in this embodiment, the spatial offset between the edge of one side and the structural feature of the other side is determined, such a tilting of at least one side surface can be considered. In this embodiment, it is of course also assumed that the tilting of the "involved" elements in the described method is at least approximately identical.
According to another embodiment of the invention, for each of the at least one further element, the method further comprises: (a) Optically capturing a further image of one side of a further element; (b) Determining a further spatial position based on the acquired further image of the further element; and (c) assembling the further component onto the component carrier based on the determined further spatial position of the further component and the determined spatial offset between the first and second structural features of the first component.
The first element as reference element can be used not only for assembling or assembling the second component, but also for in principle any number of subsequent further elements which (should) be assembled or placed onto the element carrier with high spatial precision based on the determined spatial structure information of the first side of the first element and the second side of the first element.
The number of other components processed may be less than 5000, preferably less than 2000, more preferably less than 500, depending on the particular application and the precision required.
The number of further elements which can be further processed with high accuracy based on the structural information of the first element may depend inter alia on the possible structural deviations of the element relative to the first (reference) element which will be expected or obtained. In this way, the number of further elements may depend on the scale of the production batch, wherein it is assumed that all elements of the production batch have at least substantially the same spatial structural properties.
In the case of handling shell-less electronic components (chips), they are removed directly from the wafer and placed onto a component carrier, it is conceivable, for example, that all the chips of the wafer are spatially similar so that a first chip (of the wafer) can be used as a suitable reference chip for all the other chips of the wafer. This is the case, for example, if all the chips of the wafer have been singulated with the same sawing device, which ensures that the dimensions and/or shape of the individual chips are at least approximately identical. For such further processing of the wafer, the accuracy can be further improved if, for example, only those chips are processed as "further elements" arranged with respect to the first chip (reference chip) in the same row on the wafer. This means that the first element is used as a reference element or reference chip for each row of chips on the wafer.
In this connection, it should be noted that in the processing of such semiconductor chips, the component carrier is usually a temporary adhesive foil that can be assembled, which is stretched over or at the frame. The entirety of all the chips assembled onto the foil is commonly referred to as a wafer.
According to another embodiment of the invention, the method further comprises temporarily placing at least the first element on an optically transparent placement member, wherein the first element is detected through the optically transparent placement member from top to bottom and from bottom to top. This has the advantage that at least the first element, which serves as a reference element, can be optically detected from both sides without having to move this element for this purpose. Unlike previous designs, which require manipulation of the first element after the acquisition of the first image and before the acquisition of the second image, such manipulation always results in a certain inaccuracy in the determination of the spatial offset. The acquisition of the first image and the acquisition of the second image can be performed at least substantially simultaneously, which is particularly advantageous for a smooth execution of the method.
The optically transparent placement element can be realized, for example, by means of a glass sheet. By suitable surface treatment of the glass sheet, for example by forming an anti-reflection coating, it is possible to facilitate detection of the relevant components with high optical accuracy through the glass sheet. The at least one reference mark may be attached or formed on the placement member, for example by means of a suitable milling or etching of at least one surface of the glass sheet. The reference mark may also be realized by means of a suitable reference module, which is placed on an optically transparent placement member.
According to another embodiment of the invention, the optically transparent placement member has at least one reference mark. Furthermore, the method comprises: (a) Detecting a first reference position of a reference mark in a first camera image of a first camera capturing a first image of a first side of a first element; (b) Detecting a second reference position of the reference mark in a second camera image of a second camera that captures a second image of a second side of the first element; and (c) determining a relative spatial positioning and/or relative orientation between the first camera and the second camera based on the spatial positions of the two reference positions in the two camera images.
In this regard, the exact knowledge of the relative positioning or orientation of the two cameras can be used to take account of and compensate in a suitable manner, on the basis of the image analysis of the camera images, for errors caused by imperfect spatial positioning or orientation of the two cameras with respect to one another. Therefore, the assembly accuracy can be further improved.
The described determination of the relative positioning or orientation can be performed in particular after the initial setting up of the two cameras (in the assembly machine). In addition, the described determination may also be repeatedly performed in the flow of the (larger) assembly job. Thus, undesired time drift with respect to the relative positioning or orientation of the two cameras can also be detected and compensated in an appropriate manner.
According to another embodiment of the invention, the optically transparent placement member has at least one reference mark. In addition, the method comprises: (a) Periodically detecting reference marks in the plurality of camera images; (b) Determining a position of a reference mark for and in each camera image; and (c) determining a time drift of the position of the reference mark in the plurality of camera images. The assembly of the second element and/or the at least one further element is further performed based on the measured drift.
By periodically or repeatedly detecting the reference marks as described, a time drift can be identified which has an effect on all spatial measurements, in particular on determining the spatial offset between the first and second structural features and determining the spatial position of the second and/or further element. By (quantitatively) recognizing such drift behavior, the assembly position of the second element and/or of the further element is modified in a suitable manner, whereby such time variations can be at least partially compensated for. Therefore, the fitting accuracy can be maintained at a high level for a longer period of time.
For example, drift occurs in the camera that affects the spatial measurements in an undesirable manner. Due to thermal expansion of components of the camera, such as the mount for the optics or sensor chip, optical imaging in the camera is affected, with the result that structures (here reference marks) in the camera images taken by the associated camera migrate between the camera images.
In short, detecting the first element as a reference element represents "initial measurement". After this initial measurement, the position of the at least one reference mark is observed in the further camera image. The drift is then determined based on the "wander" of the reference mark, which is compensated for by appropriate repositioning of the assembly head that places or assembles the relevant component on the component carrier during assembly of the second component or the further component.
As mentioned above, such drift is particularly caused by thermal expansion and/or stress in the associated camera. It should be noted, however, that such drift may also occur at other locations of the assembly machine, such as in gantry systems carrying the assembly head and/or associated cameras and responsible for the operation or positioning of these components.
It should be noted that the number of reference marks which are periodically detected and for this purpose determine the respective time drift within the scope of the method according to the invention is in principle not limited. In general, the greater the number of reference marks considered, the more precisely the thermal expansions and/or stresses identified in the relative assembly machine can be compensated for by appropriate positioning of the assembly head.
Preferably, the at least one reference mark is arranged at a location that does not interfere with the detection of the associated element. This means that in the detection area of the associated camera a partial area is provided for imaging the associated element and in the detection area at least one other partial area is provided spaced apart therefrom for displaying at least one reference mark. In a preferred embodiment, some of the reference marks are located in two opposite edge regions of the detection area or in a frame-shaped detection area surrounding an intermediate detection area provided for imaging the respective element.
According to another embodiment of the invention, at least one reference mark and element are detected together. This has the advantage that the time drift can be determined without having to take additional camera images, so that the method can be carried out smoothly.
In short, with each image acquisition of the element, the first element, the second element and/or the at least one further element, at least one reference mark is also detected simultaneously. The position determination of the reference mark is then performed in different image acquisitions by means of a suitable image evaluation, which can be performed time-lapse neutral with suitable processor performance and without slowing down the execution of the method.
According to another embodiment of the invention, at least two selected aerial image areas are defined on the camera chip, which aerial image areas display the respective elements and at least one reference mark. For determining the position of the reference mark and for determining the position of the element and/or the further position of the further element, only the image data of the selected aerial image area are used. This has the advantage that the amount of data that has to be transferred from the respective camera chip to the data processing device can be significantly reduced, so that a suitable image evaluation can be performed here. An important contribution to such a reduction in the amount of data is that the speed at which the method described herein can be performed is not limited by the necessary data transmission. All information obtained from capturing images of the relevant assembly process that contributes significantly to high assembly accuracy may be time-lapse neutral with respect to other (mechanical) method steps, in particular processing the relevant components.
According to another embodiment of the invention, the method further comprises: (a) Rotating the first element 180 ° about an axis of rotation oriented perpendicular to the first side of the element and/or perpendicular to the second side thereof; (b) Optically acquiring a third image of the first structural feature of the first element rotated 180 ° by means of the first camera; (c) Optically acquiring a fourth image of the second structural feature of the first element rotated 180 ° by means of a second camera; and (d) determining an additional spatial offset between the first structural feature and the second structural feature when the first element is in the 180 rotated position. The second component is further assembled to the component carrier based on the determined additional spatial offset.
By determining the spatial offset between the two structural features twice as described, the first time when the first element is in a first angular position and the second time when the element is in a second angular position rotated 180 °, the offset from the desired orientation can be identified by at least one of the two cameras. Such identification is based on the following considerations.
(A) Typically, the two cameras are oriented relative to each other such that their optical axes are arranged parallel to each other or more preferably collinear with each other. This means that in a cuboid shaped element both the first side of the element and the second side of the element are detected by the respective camera at a perpendicular viewing angle. If there is an undesired tilt of the camera at this point, the camera detects the element at a slightly tilted angle. The structural features located on the camera-facing side then appear in slightly offset positions in the associated camera image due to parallax effects. Thereby deriving a virtual spatial offset between the two structural features.
(B) In case the two cameras are perfectly parallel oriented, this virtual spatial offset does not occur. The measured real space offset between the two structural features is then in a second angular position that is diametrically opposite the corresponding real space offset in the first angular position. This shows that the "equal ratio" in the two spatial offsets is a direct measure of the camera tilt direction and range. In recognition of the geometry of the components involved in the relevant optical imaging, the (undesired) tilting of the relevant camera is taken into account during the assembly of the second element and/or the assembly of the further element and is compensated for by a suitable positioning of the assembly head when the relevant element is placed.
It should be noted that during the assembly of the longer component carrier, the described (quantitative) determination of the undesired inclination of the camera axis may also be repeated periodically for further components. In this way, a time drift of the variable tilt relative to the associated camera can be determined and taken into account or compensated for in a progressive manner, i.e. in a prospective manner, during assembly of the "subsequent" further elements.
According to another aspect of the invention, a mounting machine for mounting component carriers with electronic components is described. The assembly machine comprises: (a) a frame; (b) A housing means mounted to the frame for housing the component carrier to be assembled; (c) A gantry system having a stationary component stationarily mounted to the frame, and a movable component positionable relative to the stationary component; (d) A mounting head mounted to the movable part and configured to pick up the components and to mount the component carriers with the components after the movable part is properly positioned, wherein each component is assembled to the component carrier at a predetermined mounting position; (e) A first optical detection means for optically detecting the element from the first side; (f) A second optical detection device for optically detecting the element from a second side opposite to the first side; and (g) a data processing device communicatively coupled to the gantry system, the mounting head, and the two optical detection devices, and configured to control or operate the aforementioned method.
The assembly machine described is also based on the following recognition: the first element is optically measured as a reference element from opposite sides to determine information about an element-unique or element-specific spatial offset between the at least one optically detectable structure on the upper side of the reference element and the at least one optically detectable structure on the lower side of the reference element. Thus, given that similar offsets may occur in subsequent elements, the unique offset information for the element may be considered during assembly of the subsequent element. Thus, as described above, highly accurate assembly of a plurality of components or a series of components can be achieved in an efficient and rapid manner.
The optical detection means may for example be cameras. In this embodiment, the two optical detection means are realized by means of (a) a single camera detecting the relevant element from one side and (b) an illumination means arranged on the opposite side of the element. The illumination means illuminate the element in such a way that the camera detects the cast shadow of the element and, based on the resulting shadow image, at least the outer contour of the element can be identified.
According to an embodiment of the invention, the first optical detection means is a camera stationary with respect to the housing. The first optical detection means is preferably a so-called component-camera which detects components from bottom to top. The aforementioned optically transparent placement member may be directly or indirectly mounted to the first optical detection device or the first camera. Then, the component to be inspected can be picked up by the assembly head and placed on the placement member, and the component is inspected from bottom to top by the first camera, if necessary in combination with the reference mark formed on the optically transparent placement member.
According to another embodiment of the invention, the second optical detection means is a camera movable relative to the housing.
In conventional assembly machines, such a (second) camera is often referred to as a printed circuit board camera or component carrier camera, which recognizes the markings on the component carrier to be assembled and thus determines information about the exact positioning of the component carrier in the assembly area of the assembly machine. The second optical detection device or the second camera may be mounted to a movable part of the gantry system. It is also possible to mount directly or indirectly to the mounting head. Alternatively, a separate positioning system may also be provided for the second camera.
It should be noted that various embodiments of the present invention have been described in connection with different inventive subject matter. In particular, several embodiments of the invention are described in relation to product claims and other embodiments of the invention are described in relation to method claims. It will be apparent to those skilled in the art from this application that any combination of features belonging to other types of inventive subject matter may be implemented in addition to those belonging to this type of inventive subject matter without further elaboration.
Further advantages and features of the present invention emerge from the following exemplary description of a currently preferred embodiment. The various figures of the invention are merely not intended to be drawn to scale.
Drawings
Fig. 1 shows an assembly machine according to an embodiment of the invention with two cameras and data processing means to determine the spatial offset between structural features present on opposite sides on a component.
Fig. 2 shows a semiconductor element having an inclined side surface.
Fig. 3a to 3c show different possible solutions for optical detection elements on opposite sides.
Fig. 4a shows determining the relative position between the first camera and the second camera.
Fig. 4b shows the time drift based on the reference mark formed with a through hole on the glass sheet while measuring the underside of the element with the first camera and determining the optical distortion of the first camera.
Fig. 4c shows simultaneous measurement of the lower side and the upper side of the semiconductor element in order to determine the offset between (i) the optically identifiable first structure formed on the lower side and (ii) the optically identifiable second structure formed on the upper side.
Fig. 5a and 5b show an optically transparent support element with reference marks attached or formed thereon.
List of reference numerals:
100. assembly machine
102. Rack
104. Holding device/transfer device
110. Gantry system
112. Stationary part/stationary carrier arm
114. Movable part/movable carrying arm
120. Component supply device
130. Assembly head
140. First camera/still camera/component-camera
150. Second camera/movable camera/component carrier-camera
160. Data processing apparatus
180. Component carrier
185. Wafer with a plurality of wafers
190. Component/chip
292. Element body
293. Inclined side surfaces
294. Connection contact
296a first side/underside edge
296b second side/upper side edge
a1 Distance of
b1 Distance of
c1 Spatial offset
341. Shell body
342. First lighting device
351. Moving the second camera
352. Second lighting device
370. Optically transparent placement member/glass sheet
372. Reference marks
375. Rotatable handling tool
375a axis of rotation
376. Mobile operating tool
377. Matrix body
379. Element-stop device/suction clamp
441. Optical axis
470. Ginseng photograph
490. Element (with curved connection contact)
490c element
496a first structural feature (on the underside)
496b (upper side).
Description of the embodiments
It should be noted that in the detailed description that follows, features or components of different embodiments that are identical or at least functionally identical to corresponding features or components of other embodiments are identified with the same reference numerals or different reference numerals, which are identical in the last two letters to the reference numerals of the identical or at least functionally identical features or components. Features or components which have been explained by means of the embodiments described above are not explained in detail below in order to avoid unnecessary repetition.
Furthermore, it should be noted that the embodiments described below represent only a limited selection of possible variants of the invention. It is in particular possible that the features of the individual embodiments are combined with one another in a suitable manner, so that many different embodiments will be apparent to the person skilled in the art with the aid of the variants described in detail herein.
It should be further noted that concepts relating to space, such as "front" and "rear", "upper" and "lower", "left" and "right", etc., are applied to describe one element's relationship to another element or elements as illustrated in the figures. Thus, these concepts relating to space can be applied to orientations other than those shown in the figures. It will be understood that all of these spatial related concepts relate to the orientation depicted in the drawings for simplicity of description, but are in no way limiting, as these depicted devices, components, etc. may all occupy an orientation other than that depicted in the drawings when in use.
Fig. 1 shows a schematic view of an assembly machine 100 according to an embodiment of the invention. In the application described in the present invention, the assembly machine 100 is used to remove the components 190, which are embodied as shell-less semiconductor chips, directly from the (sawn or singulated) wafer 185 and to place or assemble them onto the component carrier 180, which in the present case is a carrier foil which is braced by a frame in a manner not shown. The mounting material assembled to the carrier foil comprises so-called artificial wafers which can be reused for manufacturing electronic components with housings, for example by means of the eWLP process described above.
The assembly machine 100 has a frame 102 that represents a frame or support structure for the various components of the assembly machine 100. The component-supply apparatus labeled 120 in fig. 1 provides an assembly process for wafer 185. The component carriers 180 to be assembled are transferred by means of the transfer device 104 into the assembly area of the assembly machine 100 and are supplied to the assembly process. The relevant component carrier 180 is fixed in the assembly position in a manner not shown, so that the transfer device also represents the receiving device 104 for the component carrier 180 to be assembled. However, with the aid of the transfer device 104, not only the component carriers 180 to be assembled are supplied during the assembly process, but also the component carriers 180 are transported away after being at least partially assembled, so that the next component carrier 180 can be assembled later.
The actual assembly process is performed by the assembly head 130. The mounting head 130 is mounted to the movable carrying arm 114 in a manner movable in a direction (double arrow x) parallel to the transfer direction (arrow x) of the component carrier 180. The movable carrier arm 114 is mounted to a stationary carrier arm 112 fixedly connected to the frame 102 and bridging the transfer device 104. The movable carrier arm 114 is movable transversely (double arrow y) with respect to the transfer direction. The stationary carrier arm 112 represents a stationary component of the gantry system 110 of the assembly machine 100 and the movable carrier arm 114 represents a movable component of the gantry system 110. In this regard, gantry system 110 enables two-dimensional movement or positioning of mounting head 130 in an xy plane that spans the x-direction and the y-direction.
Prior to the assembly process of the at least one component 190, the assembly head 130 is moved by means of the gantry system 110 to the component-supply device 120, which receives the at least one component 190 there. The assembly head is then moved over the component carrier 180 to be assembled, in which case at least one component 190 is placed on the component carrier 180.
The assembly machine 100 further includes two cameras, a stationary first camera 140 and a movable second camera 150.
According to the embodiment shown in the figure, a stationary first camera 140 is arranged between the component-supply device 120 and the assembly area in which the component carrier 180 to be assembled is located. The stationary camera 140 is directly or indirectly connected to the housing 102 and has an upward field of view, i.e., out of the page in fig. 1. As long as the mounting head 130 is positioned above the first camera 140, the first camera 140 can measure the component 190 held by the mounting head 130 from bottom to top by means of a suction jig, not shown. Thus, the first camera 140 is also referred to as an element-camera.
According to the embodiment shown in the present figure, the movable second camera 150 is mounted to the movable carrying arm 114 and is movable in the x direction indicated by the double arrow just like the fitting head 130. The second camera 150 may also be mounted directly to the mounting head 130 with a top-down view, i.e., penetrating into the page in fig. 1. The second camera 150 can identify indicia (not shown) attached to or formed on the component carrier 180 such that the second camera 150 can also be referred to as a component carrier-camera.
The assembly machine 100 further includes a data processing device 160, shown schematically by dashed lines, that is communicatively coupled to the two cameras 140 and 150 and the assembly head 130. The data processing device 160 ensures the operation of the fitting head 130 by appropriately controlling the driving motor or the actuator. In addition, according to the embodiment illustrated in the present drawing, image processing of the images captured by the two cameras 140 and 150 is also performed by the data processing device 160.
Fig. 2 shows semiconductor elements 190 singulated from a wafer by a sawing process. The inventors have appreciated in describing the present invention that in practice, such sawing process is never perfect and may result in a component 190 having a component body 292 with an inclined side surface 293. The structure 294 constructed on the upper side (second side) of the element body 292 is an electrical connection contact 294. In addition to the electrical connection contacts 294 on the upper side of the element body 292, a camera (not shown in FIG. 2) that detects the element 190 from top to bottom may recognize the edge 296b. A camera (also not shown) that detects the component 190 from bottom to top can identify the edge 296a of the underside of the component body 292.
The angle of inclination of the side surface 293 is typically different from wafer to wafer. The inventors have recognized that in the same wafer, the elements 190 derived from that wafer typically have a substantially constant tilt angle. Tilting of the side surface 293 results in a distance c1 between an edge 296b of the component body 292 that is present on the upper side and a corresponding edge 296a of the component body 292 that is present on the lower side. In the case where the inclination angle is zero, c1 is of course zero.
The center of the identification element 190 is typically performed by means of (a) a camera that views the element 190 from top to bottom and (b) another camera that views the element from bottom to top. The associated camera recognizes the distance a1 between the structure of the component-connecting contact 294 and the upper right edge 296b of the component body 292 in fig. 2 from top to bottom. The camera of the element 190 recognizes the different center positions of the element 190 from bottom to top. In fig. 2, a distance b1 smaller than the distance a1 is shown, the distance b1 representing the (horizontal) distance between the structure of the element-connecting contact 294 and the lower right edge 296a of the element body 292 in fig. 2.
Fig. 3a to 3c show different possible solutions for the optical detection element 190 on opposite sides. For simplicity of illustration, the element 190 (with inclined side surfaces) is not shown as a parallelogram as in fig. 2, but is correspondingly shown as a trapezoid.
Fig. 3a shows a currently preferred embodiment, wherein two cameras shown in fig. 1, a stationary first camera 140 and a movable second camera 150 are used for optically detecting elements 190 from both sides. To this end, the element 190 is placed on an optically transparent placement member 370, which placement member 370 is an optically high quality glass sheet according to the illustrated embodiment. The glass sheet 370 is positioned between the two cameras 140 and 150. According to the illustrated embodiment, the glass sheet 370 is mounted directly to the housing 341 of the camera 140. In addition, according to the illustrated embodiment, the glass sheet 370 also has a reference mark 372 for calibrating the relative position or orientation of the two cameras 140 and 150 with respect to each other. The first illumination device 342 associated with the first camera 140 provides bottom-up illumination of the element 190 (and reference numeral 372). This illuminates the element 190 (and reference numeral 372) from bottom to top through the glass sheet 370. Further, optical detection of the element 190 and the reference mark 372 by the first camera 140 is performed through the glass sheet 370. In addition, a second illumination device 352 is provided that is associated with the second camera 150 and illuminates the element 190 and the reference mark 372 from top to bottom. In a corresponding manner, the second camera 150 detects the element 190 and the reference mark 372 from top to bottom without the corresponding light beam having to penetrate the glass sheet 370.
To determine the "tilt" and the relative spatial offset between (a) the structure of the upper side (upper side edge) of the element 190 or the electrical connection contacts 294 formed thereon and (b) the lower side edge of the element 190, the element 190 is removed from the wafer and placed on the glass sheet 370 (between reference marks 372). Then, the spatial offset is determined from the two-sided optical detection elements 190, and taking into account the positions of the reference marks 372 shown in the two corresponding camera images, if necessary. The evaluation of the two resulting camera images is performed by two data processing means (not shown) located downstream of the respective cameras.
Fig. 3b shows measuring elements 190 from both sides, wherein only cameras 150 are used which detect elements 190 from top to bottom. To identify the upper side of the element 190, the second lighting device 352 is activated. The detection of the element 190 is performed under bright field illumination. To identify the underside of the element 190, the second lighting device 352 is turned off and the first lighting device 342 located below the glass sheet 370 is activated. Camera 150 recognizes element 190 (under dark field illumination) based on the shadow image of element 190.
Fig. 3c shows a further variant of the measuring element 190 from both sides, in which a rotatable actuating tool 375 is used. In the same way as in the case of the variant of fig. 3a and 3b, the upper side of the element 190 is detected by means of the element camera 150. For optically detecting the underside of the component 190, the camera 150 is moved away from the glass sheet 370 (see double arrow 351) so that the component 190 can be picked up from above. This pick-up is performed by a rotatable handling tool 375 having a main body 377 and a plurality of element-retaining means 379 projecting radially from the main body. According to the embodiment shown in the present figure, the element-retaining means is a suction clamp 379. Additionally, according to the illustrated embodiment, the manipulation tool 375 is movable in a translational manner (see double arrow 376) and is rotatable about an axis of rotation 375 a. The component 190 can thus be removed from the glass sheet 370 and introduced into the optical detection area of the camera 140, if necessary by means of the first illumination device 342 of the component 190 from bottom to top.
Embodiments of the present invention that are capable of determining the spatial offset between the structure on the upper side of the element and the structure on the lower side of the element with particular accuracy will be described below. Here, high accuracy is achieved, inter alia, by calibrating the camera used and by suitably taking into account the position, orientation and/or internal geometry of the camera (which, of course, varies with time) that leads to a certain aberration. These aberrations can be at least approximately compensated for in a suitable manner, in particular in image processing, by means of calibration measures described below.
The calibration is based on the measurement already mentioned above for the reference marks formed on the optically transparent placement of the element to be detected. These reference marks are detected by two cameras, a stationary first element-camera and a movable second element carrier-camera. The reference marks are arranged in the edge region of the field of view of the still camera in the focal plane of the still camera and can likewise be detected by suitably positioning the movable camera. This indicates that: both cameras accurately measure the same structure at the location where the offset is measured.
(A) To determine the relative orientation of the two cameras to each other, the same reference mark is detected by both cameras and their exact spatial position is measured in both camera images. Thereafter, the measured spatial position is saved in a memory as a reference value for a subsequent drift compensation.
(B) To determine the spatial offset (offset) between the structure on the upper side of the element and the structure on the lower side of the element, the relevant element is placed on an optically transparent placement, measurements are made from both sides, and the spatial offset is determined by evaluating two corresponding camera images. The component is then picked up by the assembly head and assembled on the component carrier taking into account the measured spatial offset.
(C) Compensating for drift: in performing (longer) assembly work flows, the reference marks are measured periodically or repeatedly (time-to-time). Here, the difference in the position of the measured reference mark is determined as compared with the value measured at the time point (a). Here, updated calibration values are determined, which can be taken into account during assembly of the further components.
A variant of this periodic drift compensation by measuring the reference marks using two cameras is to measure the reference marks on the basis of originally performing measurements on the placed elements using a stationary camera from bottom to top (see the above-mentioned procedure for determining the offset). Here, although only the drift of the stationary (component-) camera can be compensated, no (large) additional measurement time is required.
Among the several sensors of the camera, with the so-called "multi-window" function, there is the possibility of defining a plurality of image areas and transmitting only the relevant image areas (i.e. only the image areas of the elements and the reference marks) precisely into the subsequent data processing means in order to minimize the image data transmission time. One possible procedure is: the reference mark is measured in two additional measurements with the aid of two cameras at longer time intervals in order to compensate for the entire drift (as described above), and between these measurements the reference mark is measured centrally (almost) time-lapse from bottom to top with a stationary camera, while the placed element is measured in order to resolve faster in time and at least a part of the drift is corrected centrally (i.e. drift of the stationary camera) at least approximately time-lapse.
(D) In addition, errors caused by the optical axes of the two cameras being non-parallel can be identified and compensated for during the measurement of the offset. For this purpose, the offset between the upper side and the lower side of the element is determined twice. The first time in a first angular position and the second time in a second angular position in which the element is rotated 180 deg.. Here, the rotation axis is perpendicular to the surface of the optically transparent placement member. If the element has an offset between the upper side and the lower side, this offset is determined in the opposite direction due to the 180 ° rotation in the two measurements. However, if there is a skew in the optical axes of the two cameras, the offset of the two measurements is the same. The skew ratio can thus be calculated by determining the identity ratio in the offset of the two measurements. This can then be used to correct other measurements, as the skew does not change significantly over time.
Fig. 4a shows determining the relative position between (a) a stationary first camera 140 having an optical axis 441 and (b) a movable second camera 150. As can be seen in fig. 4a, two cameras (simultaneously) measure the position of the reference mark 374. Based on the position of the reference mark in the two resulting camera images, the relative spatial position and/or orientation between the two cameras can be determined.
Fig. 4b shows that measurements are made simultaneously (a) from the underside of the element 490b and (b) from both reference marks 374 using the stationary first camera 140. By repeatedly measuring the position of the reference mark 374 in a time sequence that preferably each displays a camera image of a different element 490b, the time drift that optically distorts the camera 140 can be measured.
As can be seen in fig. 4b, according to the embodiment shown in this figure, the reference mark 374 is attached to a reference sheet 470 having an opening through which the camera 140 passes the detection element 490b. According to the embodiment shown in the figure, element 490b is an element enclosed in a housing and having curved connection contacts.
Fig. 4c shows that both the underside and the upper side of the semiconductor element 490c are measured in order to determine the offset between (i) an optically identifiable first structure 496a formed on the underside and (ii) an optically identifiable second structure 496b formed on the upper side. This type of measurement from both sides corresponds substantially to the offset measurement described above in connection with fig. 3 a.
Fig. 5a and 5b each show an optically transparent support element 370 with a reference mark 372 attached or formed thereon. In the embodiment shown in fig. 5a, reference marks 372 are located in both side regions of the support element 370. The intermediate area is provided for placing the component and is free of reference marks. In the example shown in fig. 5b, the number of reference marks 372 is slightly greater, and the reference marks 372 are arranged in a frame-like edge region around the middle of the support element 370.
Note that the concept "having" does not exclude other elements and "a" does not exclude a plurality. Elements described in association with different embodiments may also be combined with each other. It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.

Claims (18)

1. A method for assembling a component carrier (180) with an electronic component (190, 490 c), the method comprising:
optically capturing a first image of a first side of a first element on which a first structural feature (296 a, 496 a) of the first element (190, 490 c) is identifiable;
optically capturing a second image of a second side of the first element (190, 490 c) at which a second structural feature (294, 296b, 496 b) of the first element (190, 490 c) is identifiable, wherein the first side and the second side are opposite each other;
Determining a spatial offset (c 1) between the first structural feature (296 a, 496 a) and the second structural feature (294, 296b, 496 b);
optically capturing an image of one side of the second element (190, 490 c);
determining a spatial position of the second element (190, 490 c) based on the acquired image of one side of the second element (190, 490 c); and
the second component (190, 490 c) is assembled onto the component carrier (180) based on the determined spatial position of the second component (190, 490 c) and the determined spatial offset (c 1) between the first structural feature (296 a, 496 a) and the second structural feature (294, 296b, 496 b) of the first component.
2. The method of claim 1, further comprising:
determining a spatial position of the first element (190, 490 c) based on (i) the acquired first image of the first side of the first element (190, 490 c) and/or (ii) the acquired second image of the second side of the first element (190, 490 c); and
the first element (190, 490 c) is assembled onto the element carrier (180) based on the determined spatial position of the first element (190, 490 c) and the determined spatial offset between the first structural feature (294, 296a, 496 a) and the second structural feature (296 b, 496 b) of the first element (190, 490 c).
3. The method according to claim 1 or 2, wherein,
the spatial position of the second element (190, 490 c) relates to an optically detectable structure (296 a, 294, 296b, 496a, 496 b).
4. The method of claim 3, wherein,
the optically detectable structure comprises electrical connection contacts (294) of the second element (190, 490 c).
5. The method of claim 3, wherein,
the second element is a light emitting semiconductor element (190, 490 c), and
the optically detectable structure comprises a light emitting surface of a semiconductor element (190, 490 c).
6. The method of claim 1, wherein,
the first structural feature comprises an edge (296 a) of a first side of the first element (190, 490 c), or the second structural feature comprises an edge (296 b) of a second side of the first element (190, 490 c), and wherein,
the acquired image of one side of the second element (190, 490 c) shows an edge (296 b) of the second element (190, 490 c).
7. The method of claim 1, for each of at least one further element (190, 490 c), the method further comprising:
Optically acquiring a further image of one side of the further element (190, 490 c);
determining a further spatial position based on the acquired further images of the further elements (190, 490 c); and
the further component (190, 490 c) is assembled onto the component carrier (180) on the basis of the determined further spatial position of the further component (190, 490 c) and the determined spatial offset (c 1) between the first structural feature (296 a, 496 a) and the second structural feature (294, 296b, 496 b) of the first component (190, 490 c).
8. The method of claim 1, further comprising:
at least the first element (190, 490 c) is temporarily placed on an optically transparent placement member (370), wherein,
the first element (190, 490 c) is detected through the optically transparent placement member (370) from top to bottom and from bottom to top.
9. The method of claim 8, wherein,
the optically transparent placement member (370) includes at least one reference mark (372, 374), wherein the method further comprises:
detecting a first reference position of the reference mark (372, 374) in a first camera image of a first camera (140) capturing a first image of a first side of the first element (190, 490 c);
Detecting a second reference position of the reference mark (372, 374) in a second camera image of a second camera (150) capturing a second image of a second side of the first element (190, 490 c); and
based on the spatial positions of the two reference positions in the two camera images, a relative spatial positioning and/or relative orientation between the first camera (140) and the second camera (150) is determined.
10. The method of claim 8, wherein,
the optically transparent placement member (370) includes at least one reference mark (372, 374), wherein the method further comprises:
periodically detecting reference marks (372, 374) in the plurality of camera images;
determining a position of the reference mark (372, 374) for and in each camera image; and
determining a time drift of the position of a reference mark (372) in the plurality of camera images; wherein,
based on the determined drift, the second element (190, 490 c) is further assembled.
11. The method according to claim 7, further comprising
At least the first element (190, 490 c) is temporarily placed on an optically transparent placement member (370), wherein,
The first element (190, 490 c) is detected through the optically transparent placement member (370) from top to bottom and from bottom to top.
12. The method of claim 11, wherein,
the optically transparent placement member (370) includes at least one reference mark (372, 374), wherein the method further comprises:
periodically detecting reference marks (372, 374) in the plurality of camera images;
determining a position of the reference mark (372, 374) for and in each camera image; and
determining a time drift of the position of a reference mark (372) in the plurality of camera images; wherein,
based on the determined drift, the at least one further element (190, 490 c) is further assembled.
13. The method according to claim 10 or 12, wherein,
the at least one reference mark (372, 374) and the first, second or further element (190, 490 c) are jointly detected.
14. The method of claim 13, wherein,
defining at least two selected aerial image areas on the camera chip, said aerial image areas displaying the respective first, second or further elements (190, 490 c) and said at least one reference mark (372, 374), wherein
For determining the position of the reference mark (372, 374) and for determining the position of the element (190, 490 c) and/or the further position of the further element (190, 490 c), only the image data of the selected spatial image region is used.
15. The method of claim 1, further comprising:
rotating the first element (190, 490 c) 180 ° about an axis of rotation oriented perpendicular to a first side and/or perpendicular to a second side of the first element (190, 490 c);
optically acquiring, by means of a first camera (140), a third image of a first structural feature (296 a, 496 a) of the first element (190, 490 c) after a rotation of 180 °;
optically acquiring a fourth image of the second structural feature (294, 296b, 496 b) of the first element (190, 490 c) rotated 180 ° by means of the second camera (150); and
determining an additional spatial offset between the first structural feature (296 a, 496 a) and the second structural feature (294, 296b, 496 b) when the first element (190, 490 c) is in a position rotated 180 °; wherein,
the second element (190, 490 c) is further assembled to the element carrier (180) based on the determined further spatial offset (c 1).
16. An assembly machine (100) for assembling a component carrier (180) with electronic components (190, 490 c), the assembly machine (100) comprising:
a frame (102);
-a housing means (104) mounted to the frame (102) for housing a component carrier (180) to be assembled;
a gantry system (110) having a stationary component (112) stationarily mounted to the gantry (102) and a movable component (114) positionable relative to the stationary component (112);
-a mounting head (130) mounted to the movable part (114) and configured to pick up elements (190, 490 c) and to mount the element carrier (180) with the elements (190, 490 c) after the movable part (114) is properly positioned, wherein each element (190, 490 c) is assembled onto the element carrier (180) at a predetermined mounting position;
first optical detection means for optically detecting the first element (190, 490 c) from the first side;
second optical detection means for optically detecting said first element (190, 490 c) from a second side opposite to said first side; and
A data processing device (160) communicatively coupled to the gantry system (110), the mounting head (130), and the two optical detection devices, and configured to control the method of claim 1.
17. The assembly machine (100) of claim 16, wherein,
the first optical detection device is a first camera (140) stationary with respect to the housing.
18. The assembly machine (100) of claim 16, wherein,
the second optical detection means is a second camera (150) movable relative to the housing.
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