Method and device for sawing a substrate with electronic components

Abstract

The invention relates to a sawing device (1) for sawing a substrate with electronic components (2), including a rotatable sawing blade (3), a substrate carrier (5) that is moveable relative to the sawing blade (3), and control means for movement of the sawing blade (3) and the substrate carrier (5); whereby the substrate carrier (5) has a base part (6) and a substrate carrying part (7), which parts are relative displaceable, and between which parts a load sensor (10,11,12,13,14) is attached. The invention also relates to a substrate carrier (5) for such a sawing device (1) and a method for controlled sawing a substrate.

Description

[0001] Method and device for sawing a substrate with electronic components

[0002] The present invention relates to a sawing device for sawing a substrate with electronic components, comprising a rotatable sawing blade, a carrier for holding a substrate, and control means for controlled movement of the sawing blade and the substrate carrier. The invention also relates to a method for controlled sawing a substrate with electronic components.

[0003] In a later stage of electronic components fabrication, an assembled configuration of fabricated electronic components, often an assembly of plural encapsulated electronic components attached on a common carriers (for instance a wafer, a lead frame or a board), may be separated (singulated, diced, cut) or at least partially separated (scratched, partially cut) to obtain more or less individualised (encapsulated) electronic components. An example of such fabrication is the production of semiconductors (IC’s) where a semiconductor package substrate normally comprises a plurality of semiconductors that are often encapsulated with a shared (moulded) housing thus forming packages. Such packages of semiconductors are divided into individual (separated) semiconductor packages during a singulation / separation operation. The at least partial separation may take place through machining, e.g. sawing with a rotating saw blade or scratching, during which at least partial separation operation the package of semiconductors, and the already partly or fully separated electronic components, are securely held by a carrier or chuck. For holding the electronic components, or more precise for holding the carries (parts) on which the semiconductors are attached, the carrier may be provided with openings that are connected to an underpressure source (a pressure lower than the ambient pressure). In practise the carrier holds the package(s) of semiconductors upside down and a rotating sawing blade moves below the carrier such that the separating sawing lines are made in the package(s) of semiconductors. The position of the carrier (or the position of the sawing blade) may also be rotated to make sawing lines in the package(s) of semiconductors in for instance rectangular directions. As part of the separating process, chips and / or other debris may be produced while often during the separation also a liquid coolant is used. The requirements in production accuracy in this type of technique are particularly high in particular the shape requirements (accuracies in the order of in pm’s) and the maximum load of the electronic components during the production.

[0004] US patent publication US 6,021 ,696A discloses a cutting method for cutting an object that is supported on a table, wherein a variable load received by the object during cutting is detected and based on said detection the force exerted on the object is adjusted. Further, the European patent EP 0166 064 discloses an apparatus that can detect cutting forces acting on a material to be cut.

[0005] The problem of the prior art solutions is that there are only limited opportunities for process control during sawing substrates with electronic components while the demand for accuracy during this process is particularly large as explained above.

[0006] Hence, the goal of the present invention is to overcome the disadvantage of the prior art equipment and processes of sawing substrates with electronic components and to provide a sawing device and a method for enhanced process control for sawing substrates with electronic components.

[0007] To realise this goal the present invention provides a sawing device for sawing a substrate with electronic components, comprising: a rotatable sawing blade, a substrate carrier for holding a substrate, which substrate carrier is moveable relative to the sawing blade, and control means for controlled movement of the sawing blade and the substrate carrier; wherein the substrate carrier comprises a base part and a substrate carrying part, which substrate carrying part is displaceable connected to the base part, and between which substrate carrying part and base part at least one load sensor is attached, for measuring a load (force / torque) that is exerted between the base part and the substrate carrying part. A controlled relative movement of the sawing blade and the substrate carrier determines the location and, to a large extent, also the process conditions under which saw cuts in the substrate with electronic components are made. By the presence of at least one load sensor between the base part and the substrate carrying part of the carrier the loads exerted information can be obtained during the sawing process over the loads exerted by the sawing blade onto the substrate with electronic components. The at least one load sensor measures a load enacted by the saw blade on the substrate held by the carrier which provides a better insight in the sawing process. For instance differences in the quality of the product to be sawed may be registered which provided product related information that may be stored and used for subsequent processing and / or may be linked to the singulated products as a quality indication. Also in the sawing of subsequent comparable substrates with electronic components the sawing process may be adapted (think e.g. of slower / faster relative movement of the sawing blade and the carrier at specific locations and or faster / slower rotating the sawing blade) or even in process, thus during an sawing operation of a substrate with electronic components the relative movement of the of the sawing blade and the carrier and / or the rotation speed of the sawing blade may be adapted, to further optimise the sawing process. The additional option of integrated saw load measurement not only enables “insitu process control” but this may also enable optimizing the production capacity of a sawing device. The advantages are thus that the sawing process may - both in process, feed forward and feedback - be optimised and that data may be used for e.g. process analysis, steering subsequent process steps and / or product quality information. The present invention thus as a general advantage provides more information (data) as well as the opportunity to better control the sawing process. Additionally to the already mentioned advantages prior art sawing devices are simple to convert to the sawing device according to the present invention as only the substrate carrier has to be exchanged for a substrate carrier comprising a base part, a substrate carrying part that is displaceable connected to the base part, and at least one load sensor attached between the substrate carrying part and the base part of the carrier. Such an isolated substrate carrier, thus without the further technical features as mentioned in claim 1 is also in its individual form part of the present invention.

[0008] Between the substrate carrying part and the base part also at least two load sensors may be attached. This helps to realise a stable coupling of the substrate carrying part and the base part. Also the sensors may be sensitive in distinctive directions and / or the sensors may be coupled to a central data processing unit. Different types of load sensors may be applied, for instance also referred to as force measuring cells, and typical cost effective load sensors are normally sensitive in only one direction. However alternatively also one or more advanced load sensors may be used that are sensitive in plural directions, e.g. for instance in various linear directions as in a rotational (torque measuring), in which case less load sensors are required to get an insight in the load of substrates with electronic components during the sawing operation. However in case load sensors are applied that are sensitive in only one direction (or a limited number of directions) the use of plural (two or even more preferably at least three) load sensors may be attached between the substrate carrying part and base part of the carrier. For instance one load sensor may be sensitive (and measuring a load enacted) in a X- orientation parallel to the substrate contacting surface of the carrying part, while a second load sensor may be sensitive (and measuring a load enacted) in a Y- orientation parallel to the substrate contacting surface of the carrying part, whereby the X-orientation and the Y-orientation mutually enclose an angle, preferable a perpendicular angle. Furthermore also a third load sensor may applied that is for instance sensitive (and measuring a load enacted) in a Z-orientation registering a rotational load perpendicular to the substrate contacting surface of the carrying part. But also including a sensor active in a direction perpendicular to the substrate contacting surface of the carrying part is an option. To enhance the sensitivity at least one load sensor may at least be sensitive in both a forth and back direction.

[0009] To guarantee that all relevant loads acting between the base part and the substrate carrying part are registered by the load cell(s) the (mechanical load carrying) interconnection of the base part and the substrate carrying part is preferably realised with exclusively the load sensor(s). The substrate carrier may however also comprise a flexible seal between the base part and the substrate carrying part that for instance may enables to maintain a vacuum between the base part and the substrate carrying (when the flexible seal is gas tight) as such a vacuum is useful to provide an underpressure to the product holding apertures normally present in the substrate contacting surface. The seal may also only be provided to prevent the space between the base part and the substrate carrying to be polluted, in which case the sealing requirements are less stringent. Such a seal (that is not taking substantial mechanical loads and is designed such that it is not influencing the measurements of the load cell(s)) may for instance be formed by a labyrinth seal, a lip seal and / or a round hollow seal. Alternatively to supply and / or discharge of a vacuum or underpressure the substrate carrier may comprise at least one vacuum channel extending through the substrate carrying part and the base part, e.g. in the form of a flexible hose, so that a gas tight sealing between the substrate carrying part and the base part is not required, only a shieling against pollution of the space between the substrate carrying part and the base part would be sufficient.

[0010] For process analysis, steering previous and / or subsequent process steps, and / or for collecting product quality information the sawing device may comprise one or more controllers connected to the load sensor(s), as well as that the controller may be connected with a saw blade drive and control means for controlled relative movement of the sawing blade and the substrate carrier, to control a rotational velocity and / or movement of the saw blade relative to the substrate carrier based on the measured loads. The controller(s) make the sawing device an intelligent processing tool that enables further process optimization as well as the steering / controlling of previous and / or later process steps. It also enables a better quality control even a quality control on an individual at least partial separated product level.

[0011] As mentioned before the present invention also includes a substrate carrier for a sawing device for sawing a substrate with electronic components, comprising a base part and a substrate carrying part, which substrate carrying part is displaceable connected to the base part, and between which substrate carrying part and base part at least one load sensor is attached, for measuring a load that is exerted between the base part and the substrate carrying part. Such a substrate carrier is also disclosed as a part of the sawing device according to the present invention but is also in its isolation part of the present invention. Also all the optional limitations and preferred embodiments of the substrate carrier as part of the sawing device according to the present invention are in their isolated form (thus without the technical features of the sawing device except for the substrate carrier) part of the present invention.

[0012] The present invention also relates to a method for controlled sawing a substrate with electronic components, preferably by making use of a sawing device according to the present invention, comprising the method steps: A) holding a substrate with electronic components with a substrate carrier in particular a substrate carrier according the present invention; B) moving the substrate carrier holding a substrate relative to a rotating sawing blade such that the substrate is cut by the sawing blade; and C) measuring in at least one direction the load enacted by the sawing blade on the substrate during the sawing with at least one load sensor embedded in the substrate carrier. With this method the advantages as listed above in relation to the sawing device according to the present invention may be realised, which advantages are here included by reference in relation to the method according to the invention. In respect of the method according to the present invention the word “cut” should be interpreted broadly as including all types of milling processes, cutting including laser and water cutting, scratching and other surface intruding processes. The cutting may both completely pass though the substrate as penetrate only partially in the substrate. In a preferred embodiment the method may also include a method step D) controlling the rotational velocity of the sawing blade and / or the relative movement of the substrate carrier and the sawing blade based on the load measured in step C). By measuring / registering the loads exerted during sawing of a substrate with electronic components the sawing process may be optimised and additional information becomes available om product quality.

[0013] To have a better insight in the sawing loads exerted onto substrates with electronic components during step C) the load enacted by the sawing blade onto the substrate held by the substrate carrier may be measured in at least two different directions, for instance in X-, Y-, Z-directions and / or rotational loads as is explained in more detail above. The method may use the sawing device for sawing a substrate with electronic components according to the present invention as such sawing device is provided with the sensors to do so. A further interactive improvement of the method may include that steps C) and / or D) are repeated and the controlling in step D) being guided by artificial intelligence. Part of a more intelligent processing of the data generated by the method according to the invention may be the storage of (load) processing data enabling amongst others actual and future process optimization and obtaining individual product quality information. Part of such intelligent method for controlled sawing a substrate with electronic components may be the storage of data generated.

[0014] The invention will be further elucidated on the basis of the non-limitative exemplary embodiments shown in the following figures. Corresponding elements are designated in the figures with corresponding reference numerals. Herein shows: figure 1 a schematic perspective view on a sawing device according to the present invention; figure 2 a cutaway view on the inside of a handler according to the present invention and being part of the sawing device according to the present invention; figures 3A - 3C three schematic side views of intersections through the side of a handler according to the present invention; and figure 4 a schematic perspective view on a side of the substrate carrier according to the present invention facing a substrate with electronic components to be held.

[0015] Figure 1 schematically shows a sawing device 1 for sawing a substrate with electronic components 2, including a circular rotatable sawing blade 3 that is driven by a saw drive 4. The substrate with electronic components 2 is held by a substrate carrier 5 which is moveable (as illustrated by the arrows Ri, R2, R3) relative to the sawing blade 3 for instance by a - not illustrated here - handler or robot arm. The substrate carrier 5 has a base part 6 and a substrate carrying part 7 which substrate carriers part 6, 7 are mutually displaceable connected. Between these substrate carrier parts 6, 7 at least one load sensor is attached as will be illustrated in figure 2. By relative movement (R1 , R2, R3) of the substrate carrier 5 that carries a substrate with electronic components 2 and the circular - now rotating - sawing blade 3 plural linear cuts may be made in the substrate with electronic components 2 such that electronic components are at least partially separated (singulated, individualised, scratched, partially cut) from each other. On the top of the substrate carrier 5 a discharge pipe 8 is shown which is used for creating an underpressure / vacuum at the side of the substrate carrying part 7 facing the substrate with electronic components 2 (see also figure 4).

[0016] Figure 2 shows the substrate carrying part 7 in a situation wherein the base part 6 of the substrate carrier 5 is removed (thus providing a view in the spacing between the base part 6 and the substrate carrying part 7). To the substrate carrying part 7 five load sensors 10, 11 , 12, 13, 14 are one-sided attached, while the other side of the load sensors 10, 11 , 12, 13, 14 is to be attached to the - in this figure removed - substrate carrier base part 6. The parallel attached load sensors 10, 1 1 are sensitive in an X-direction and the also parallel attached load sensors 12, 13 are sensitive in an Y-direction. The centrally allocated load sensor 14 is sensitive in a rotational direction R. The load sensors 10, 11 , 12, 13, 14 enable the measuring of loads that are acting between the base part 6 and the substrate carrying part 7 during the sawing of a substrate with electronic components 2 (see figure 1 ) held by the side of the substrate carrying part 7 that is faced away from the side as shown in figure 2 (but that is shown in figure 4). All the load sensors 10, 11 , 12, 13, 14 are connected (connections represented with reference sign 15) with control means 16, e.g. for storage of the processing data in a database 17 and / or for the controlling the movement of the sawing blade 3 and the handler 5 (as illustrated by the arrows Ri , R2, R3 in figure 1 ).

[0017] In figures 3A-3C schematic side views of intersections through the sides of the substrate carrier base part 6 and the substrate carrying part 7 are shown with spacing 20 between these parts 6, 7. Also shown is load sensor 10 that with a one sided attachment 21 to the substrate carrier base part 6 and an opposite (of the load sensor 10) sided attachment 22 to the substrate carrying part 7. During operation in the spacing 20 an underpressure / vacuum may be present which requires that the spacing 20 is separated from the environment. For this separation, which also requires that the substrate carrier base part 6 and the substrate carrying part 7 are mutually moveable (with a limited freedom of movement that enables the activation of the load sensors 10, 11 , 12, 13, 14), three alternatives of flexible seals 23, 24, 25 are shown. Figure 3A shows a labyrinth seal 23, figure 3B shows a round hollow seal 24 and figure 3C shows a lip seal 25.

[0018] Figure 4 shows a perspective view on a contact side 30 of the substrate carrying part 7 of the substrate carrier 5 facing the substrates with electronic components 2 (see figure 1) to be held. Also visible is the discharge pipe 8 connected to the substrate carrier base part 6 for generating an underpressure / vacuum between the substrate carrier base part 6 and the substrate carrying part 7. The underpressure / vacuum is guided to a plurality of openings 31 in the contact side 30 of the substrate carrying part 7. These openings 31 are to hold the substrates with electronic components 2 before, during and after the sawing process takes place. After completion of the sawing process, thus when the electronic components are at least partly individualised, the at least partially separated electronic components are released on controlled positions by raising the pressure in the spacing 20 between the substrate carrier base part 6 and the substrate carrying part 7 so that also in the openings 31 in the contact side 30 of the substrate carrying part 7 the underpressure / vacuum is cancelled.

Claims

Claims1 . Sawing device for sawing a substrate with electronic components, comprising:- a rotatable sawing blade,- a substrate carrier for holding a substrate, which substrate carrier is moveable relative to the sawing blade, and- control means for controlled movement of the sawing blade and the substrate carrier; characterized in that the substrate carrier comprises a base part and a substrate carrying part, which substrate carrying part is displaceable connected to the base part, and between which substrate carrying part and base part at least one load sensor is attached, for measuring a load that is exerted between the base part and the substrate carrying part.

2. Sawing device according to claim 1 , characterized in that between the substrate carrying part and the base part at least two load sensors are attached.

3. Sawing device according to claim 2, characterized in that between the substrate carrying part and the base part at least three load sensors are attached.

4. Sawing device according to any of the preceding claims, characterized in that at least one load sensor is at least sensitive in both a forth and back direction.

5. Sawing device according to any of the preceding claims, characterized in that the base part and the substrate carrying part are interconnected with only one or more load sensors.

6. Sawing device according to any of the preceding claims, characterized in that the substrate carrier comprises a flexible seal between the base part and the substrate carrying part.

7. Sawing device according to claim 6, characterized in that the seal is a labyrinth seal, a lip seal and / or a flexible round hollow seal.

8. Sawing device according to any of the preceding claims, characterized in that the substrate carrier comprises at least one vacuum channel extending through the substrate carrying part and / or the base part.

9. Sawing device according to any of the preceding claims, characterized in that the sawing device comprises a controller connected to each load sensor, to a saw blade drive and to the control means for controlled relative movement of the sawing blade and the substrate carrier, to control a rotational velocity and / or movement of the saw blade relative to the substrate carrier based on the measured loads.

10. Substrate carrier for a sawing device for sawing a substrate with electronic components, comprising a base part and a substrate carrying part, which substrate carrying part is displaceable connected to the base part, and between which substrate carrying part and base part at least one load sensor is attached, for measuring a load that is exerted between the base part and the substrate carrying part.11 . Method for controlled sawing a substrate with electronic components by making use of the sawing device according to any of claims 1-9, comprising the method steps:A) holding a substrate with electronic components with a substrate carrier, in particular a substrate carrier according to claim 10;B) moving the substrate carrier holding a substrate relative to a rotating sawing blade such that the substrate is cut by the sawing blade; andC) measuring in at least one direction the load enacted by the sawing blade on the substrate during the sawing with at least one load sensor embedded in the substrate carrier.

12. Method according to claim 11 , characterized in that the method also includes a method step D) controlling the rotational velocity of the sawing blade and / or the relative movement of the substrate carrier and the sawing blade based on the load measured in step C).

13. Method according to claim 11 or 12, characterized in that during step C) the load enacted by the sawing blade onto the substrate held by het substrate carrier is measured in at least two different directions.

14. Method according to any one of claims 11 - 13, characterized in that steps C) and / or D) are repeated and the controlling in step D) is guided by artificial intelligence.

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