WO2009091333A2

WO2009091333A2 - Method and apparatus for laminating a bumped wafer

Info

Publication number: WO2009091333A2
Application number: PCT/SG2008/000014
Authority: WO
Inventors: Siu Mun Leong; Peng Fah Low; Kee Meng Joey Ng
Original assignee: Lintec Singapore Pte Ltd
Current assignee: Lintec Singapore Pte Ltd
Priority date: 2008-01-14
Filing date: 2008-01-14
Publication date: 2009-07-23
Anticipated expiration: 2010-07-14
Also published as: WO2009091333A3

Abstract

An improved lamination process by reducing the occurrence of air bubbles traps between the wafer and the backgrinding tape laminating the backgrinding tape in a vacuum environment. The method includes holding a precut laminate tape by vacuum suction means and blowing air in an airbrushing manner to push and laminate the tape onto the wafer. In a first embodiment, the centre of the laminate tape is initially pressed to laminate onto the corresponding part of the wafer before the air blow is expanded to cover the rest of the tape while air is evacuated from the ambience at a location below the wafer. In a second embodiment, a peripheral segment of the tape is first pressed to laminate onto the corresponding part of the wafer and then air blow is expanded across the tape and wafer to complete the lamination, while air is evacuated from lamination chamber. An apparatus implementing our methods is also disclosed.

Description

METHOD AND APPARATUS FOR LAMINATING A BUMPED WAFER

TECHNICAL FIELD

[001] The present invention relates to a method and apparatus for laminating a backgrinding tape to the surface of a semi-conductor wafer having bumps. The lamination process includes providing means to roll or press the tape over the bumped surfaces of the wafer in a vacuum chamber.

BACKGROUND ART

[002] Semiconductor wafers which fabrication has been completed are usually thinned, in which a backgrinding process is carried out on the underside surface of the semiconductor wafer prior to or after dicing operation so as to minimize the final die thickness prior to packaging. The upper surface of the wafer (i.e. the surface profile formed with the die's circuitry) therefore needs to be protected, typically by laminating it with a protective tape made from a flexible film, for example, vinyl chloride tape or the like which is known as the backgrinding or BG tape, to avoid any damages to the circuitry during dicing and/or backgrinding processes. [003] Methods for adhering a protective tape to a wafer are known in the prior art. In one method, the protective tape is laminated after being precut to the same shape as the wafer, whereas in another method the protecting tape is first applied to the wafer and then cut to match the wafer shape. Typically, means is required to press down the laminating tape so as to adhere to the wafer surface.

[004] US-4, 787,951 (Fujitsu) has disclosed the use of multiple rollers to laminate a semiconductor wafer with an adhesive tape in a vacuum chamber, in which air pressure is reduced to about 750 mmHg by a vacuum pump. The rollers consist of rubber rollers having different axial length and act on the wafer independently of each other so that the adhesive tape can be laminated uniformly to the whole surface of wafer even if the wafer surface is uneven. They are each supported on a roller frame and arranged in parallel to one another.

[005] Since the rollers are independent of each other, the physical pressing action consists of steps as follows. Pressure is first exerted to the central portion of the wafer surface by the roller having shortest axial length. Then, pressure is exerted on a larger area by rollers having longer axial length. Finally, the air valve is opened to introduce atmospheric air into the chamber and due to this air pressure increment; adhesive tape can be completely laminated to the whole wafer surface. [006] Japanese patent publication JP-63074871 (Tokyo Shibaura Electric) discloses the use of compressed air feed through multiple passages of a curved pressure surface to gradually press down protective tape onto a wafer surface so that no air bubbles are trapped in between. However, the process is not carried out in vacuo.

[007] Another Japanese patent publication JP-2006-26989 (Nichigo Morton) has disclosed a vacuum chamber in laminating a printed circuit board wherein the resin film laminate may be reused 10,000 times. Compressed air is used to press the laminate sheet into adhesion under pressure. Its has effective adhesion to the fine pattern of resin layer atop a base material of a printed circuit board and thus useful to the build up method of construction and manufacturing a multi layered circuit board. It is obvious however that the surface protrusions of a printed circuit board have far bigger height and pitch than that of a silicon wafer's bumps.

[008] For the roller method, in order to maintain the protecting tape in a stretched state so as to prevent wrinkles formation, a tensile force is put on along the feeding direction of the protecting tape and along the opposite direction thereof. The tensile force applied is not adjustable and thus a shrinkage force will act on the applied tape and creates risks such as warpage or rupture if the tensile force is too high. Whereas, if the tensile force is too low, wrinkles may form in the protecting tape and air bubbles may enter between the protecting tape and the wafer, creating such risk that the wafer cannot be used for grinding process.

[009] In our present invention, we endeavour to overcome the aforesaid disadvantages, particularly with respect to the inflexibility of the roller method and the issue of air bubbles trapped being increased with the use of air jets in pressing the laminate tape onto the wafer surface.

SUMMARY OF DISCLOSURE

[010] In our present invention, we endeavour to improve upon the lamination process by reducing the occurrence of air bubbles traps between the wafer and the backgrinding tape by means of laminating the backgrinding tape in a vacuum environment. The lamination process is conducted in a vacuum environment of a chamber and uses air to press the tape over the bumped wafer. This eliminate any physical contact with the wafer and is thus suitable for thin wafer grinding which usually faces micro-crack at wafer edge induced by cutting of backgrinding tape, which lamination may be less than perfect using conventional roller method.

[011] In the first aspect of our invention, a method is provided for laminating a semiconductor wafer surface with bumped topography in a substantially fluid- proof ambience, the method comprising the steps of: (a) pre-cutting a laminate tape comprising at least an adhesive surface suitable for backgrinding protection to substantially cover said wafer's planar shape or outline;

(b) holding said laminate tape by vacuum suction means in a substantially planar orientation with said laminate tape's adhesive surface facing said wafer surface to be laminated;

(c) placing said laminate tape and said wafer in mutual outline alignment;

(d) releasing said laminate tape from said vacuum suction means;

(e) blowing a fluid medium at about centre of said laminate tape to press said laminate tape's adhesive surface thereat against said wafer's corresponding surface,

(f) further blowing said fluid medium to fan out radially from said central portion to the periphery of said laminate tape thereby pressing said laminate tape's adhesive surface over said wafer's corresponding surface; and

(g) substantially removing fluid medium from said chamber, including from spaces in between said laminate tape and said wafer surface.

[012] In an alternative embodiment of our aforesaid method, the steps for blowing fluid medium at a part of the laminate tape and subsequent steps are varied by: (e) blowing a fluid medium at about one peripheral segment of said laminate tape, pressing said laminate tape's adhesive surface thereat against said wafer's corresponding surface, (f) further blowing said fluid medium to diverge from said peripheral segment to fan across said laminate tape thereby pressing said laminate tape's adhesive surface beyond said peripheral segment over and across said wafer's corresponding surface; (g) substantially removing fluid medium from said chamber, including from spaces in between said laminate tape and said wafer surface.

[013] In a first preferred embodiment, the laminate tape used further comprising a release liner covering the adhesive surface, and wherein said release liner is removed to expose said adhesive surface prior to lamination. Preferably, a leading edge of the release liner is first detached and the rest of the liner is removed when the laminate tape is moved into alignment with said wafer. Preferably still, the leading edge detached is less than 10 mm.

[014] In a second aspect of our invention, the wafer may be placed in alignment with the laminate tape; or alternatively, the laminate tape is placed in alignment with the wafer. The laminate tape is preferably released initially at about the centre with the periphery still held by the vacuum suction means. Preferably, the fluid medium that is blown at about the centre of the laminate tape is increased to sufficient force to detach the periphery, and whence, of the whole laminate tape, from the vacuum suction means. Preferably, the periphery is further released from the vacuum suction means. [015] In a third aspect of our invention, the laminate tape is released initially at about one peripheral segment with the fluid medium blown thereat and moved there beyond to detach the remainder of the laminate tape from the vacuum suction means. Preferably, the laminate tape is released initially at about one peripheral segment with the fluid medium blown thereat, and remainder of said laminate tape is expansively released and wherein the fluid medium is blown correspondingly across said remainder of said laminate tape.

[016] In a fourth aspect of our method, the blowing is provided as an effect of residue air being sucked out from parts of the fluid-proof ambience.

[017] We endeavoured to achieve the foregoing methods with an apparatus for laminating a semiconductor wafer with bumped topography in a substantially fluid-proof ambience, comprising: - a table adaptively disposed to hold a semiconductor wafer to be laminated; an upper carriage movable between a first position at which laminate tape may be picked up, and a second position at which said laminate tape may be released to laminate said semiconductor wafer; said upper carriage is provided with reversible fluid flow control means for picking up and releasing said laminate tape; a tape dispenser wherein laminate tapes are dispensable therefrom for picking up by said upper carriage; wherein at least the table and upper carriage are disposed in a fluid- proof chamber and provided with means for controlling fluid flow thereinto.

[018] In one aspect of our apparatus, the table is provided with a plurality of outlets distributed at least at one of under and around the wafer-covering area for the removal of fluid via said outlets by the fluid-evacuating means.

Preferably, the table is provided with at least an outlet provided at a position to be covered by a wafer with an aperture at an unfabricated part, including at any one of unpopulated part, inter-die alleys or junction of the wafer, through which fluid may be drain out. Preferably, the fluid draining out of the outlets is operated to be synchronised with a predetermined laminating sequence of the laminate tape over the wafer surface.

[019] In another aspect of our apparatus, the tape dispenser dispenses laminate tape which adhesive surface is covered by a release liner. Preferably, the laminate tape dispensed is pre-cut to substantially cover the semiconductor wafer. Preferably, a leading edge of the release liner is first detached by the tape dispenser and the rest of the release liner is detached as the upper carriage picks and holds the laminate tape and moves from the first position to the second position. More preferably, the leading edge detached is less than

10 mm.

[020] In a third aspect of our apparatus, the fluid flow control means enables the upper carriage to be operated to provide vacuum suction effect to pick up the laminate tape from the tape dispenser. Preferably, the fluid flow control means enables the upper carriage's operation to be controlled to vary and alternate between suction, stop (i.e. non-operating) and reverse (i.e. blowing) operations to control pick up, holding, release and driving of the laminate tape.

[021] In a fourth aspect of our apparatus, the upper carriage is configured with a plurality of outlets distributed over a ceiling surface area to be covered by a laminate tape being picked up. Preferably, during fluid removal, the plurality of outlets are sequentially opened to enable fluid flow via said outlets to release the laminate tape and drive the lamination onto the wafer according to a predetermined laminating sequence of the wafer surface. More preferably, fluid is allowed to be drawn in initially at about central portion of the laminate tape thereby releasing and driving the central portion of said laminate tape to laminate onto corresponding portion of the wafer, and thence fan out to the rest of the tape to laminate completely onto the wafer.

[022] In an alternative embodiment, the fluid is allowed to be drawn in initially at about one peripheral segment of the laminate tape, pressing the laminate tape's adhesive surface thereat against said wafer's corresponding surface, and thence, drawing the fluid to laminate said tape across said wafer's entire corresponding surface. [023] Apart from the aforementioned apparatus embodiments, our invention may be implemented in various other products including a semiconductor wafer, device, die or package, and appliances thereof.

LIST OF ACCOMPANYING DRAWINGS

[024] We would like to refer to the drawings listed below, with the accompanying detailed description that follows, for further and better understanding of our invention. Specific embodiments of our method are described hereinafter as implemented in our proposed apparatus as non- limiting exemplary embodiments with respect to our invention, in which:

[025] FIGURE 1 shows a side elevation view of a console unit comprising an apparatus according to our invention;

[026] FIGURE 2 refers to a top or plan view of the apparatus of FIG. 1 ;

[027] FIGURE 3 illustrates a front elevation view showing the 3 main component mechanisms of our apparatus;

[028] FIGURE 4 shows the 3 main components of our apparatus in detail; [029] FIGURES 5A, 5B, 5C and 5D show schematic representations of the laying of the laminate tape according to one embodiment of our invention;

[030] FIGURE 6 shows schematic representations of the lamination over topographic features of a wafer according to our invention;

[031] FIGURE 7 shows a schematic representation of the laying of the laminate tape according to another embodiment of our invention;

[032] FIGURE 8 illustrates one embodiment of the apparatus according to our invention in schematic perspective view;

[033] FIGURE 9 represents a schematic elevation view of the apparatus of FIG. 8 wherein an upper carriage is shown disposed under an upper half of a laminating chamber and shown picking up a laminate tape;

[034] FIGURE 10 shows in schematic elevation view the apparatus of FIG. 8 wherein the upper carriage is positioned over the wafer on a table disposed within a lower half of a laminating chamber; and

[035] FIGURE 11 shows in schematic elevation view the apparatus of FIG. 10 wherein the upper and lower halves of the laminating chamber are closed with the upper carriage placed over the wafer on the table in laminating position. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[036] The general embodiment of the method according to our invention may be implemented by an apparatus proposed and described hereinafter. To enable the proposed operation to be implemented in a vacuum ambience, a fluid-proof cabinet needs to be constructed such as one of the size and dimension shown in side view in FIGURE 1 and the corresponding plan view in FIGURE 2.

[037] Generally, our proposed apparatus comprises a console or cabinet of a size as shown in FIG. 1 and FIG. 2 relative to a human figure shown. Swing doors (12, 13, 14) may be provided to enable direct access to certain components for supply and maintenance of parts of the apparatus such as to wafer cassette loading and wafer placing mechanism (20), laminate tape reel loading and dispensing mechanism (30) and laminating chamber (40).

[038] The principal components of the apparatus for the lamination process may be shown better in FIGURE 3 in front elevation view, and in detailed disassembled view in FIGURE 4. The laminate tape reel loading and dispensing mechanism (30) includes, as one of the principal components, a tape dispenser (32). The apparatus is also proposed to be provided with a mechanism (50) for loading a cassette of stacked wafers whereby each wafer may be picked in precision by a robotic arm from the cassette and placed on a second principal component, i.e. a table (52) comprising a planar surface for laying and holding a wafer (54) to be laminated and which is optionally adjustable or capable to be aligned for a laminate tape to be adhered thereon. Preferably, the table (52) is provided with means for holding and aligning the wafer (54), either by precise adjustments to the wafer (54) or adjustments to the table's planar position, to be laminated by a laminate tape poised thereabove.

[039] Another mechanism is provided at above the table and which is capable of moving an upper carriage (72), which is a third principal component, between a position above the tape dispenser (32) and above the table (52), i.e. in a back-and-forth movement between the 2 positions, including lowering the upper carriage (72) at the respective positions to pick up the laminate tape and to place and adhere the tape onto wafer (54).

[040] Central to the concept of our invention is the use of fluid pressure differential in actuating certain operational steps in the lamination process. As such, removal or injection of fluid in the ambience where a particular operation or step occurs is important and it is essential that at least a fluid proof chamber is provided for the purpose. In the following embodiments, atmospheric air which has been dried, i.e. with the moisture content substantially removed, is used as the fluid which flow and content is to be controlled in our apparatus. However, it is apparent to a skilled person that inert gases may be used to minimize possible redox reactions or static discharge during the lamination process. [041] At least the table (52) and the upper carriage (72) are to be provided in a gas-proof chamber during the lamination process, i.e. when the adhesive surface of the laminate tape is pushed downwardly to adhere on the wafer's topographic surface. This will enable the tape pick-up and pushing to adhere to the wafer (54) to be practiced with the fluid pressure differential according to our invention's concept.

[042] At the tape dispenser (32), the laminate tapes to be dispensed may be provided in the form of a reel of supply in a bobbin (34) wherein the laminate tape (35) is pre-cut (35a) to a shape that substantially cover the corresponding topographic surface of the wafer (54) with a tolerance of about 2 mm, i.e. so that the wafer's planar shape or outline is covered adequately by the pre-cut size and shape for the subsequent backgrinding operation. With this tolerance, contact with the wafer (54) may be eliminated and is thus suitable for thin wafer grinding which usually face micro-cracks at the edge of the wafer induced by cutting of backgrinding tape during backgrinding tape laminating in conventional roller method.

[043] The pre-cut laminate tape (35a) may be detached from the continuous strip of tape along the pre-cut lines and the detached piece of laminate tape (35a) held by the upper carriage (72) with the adhesive surface facing downwards. The laminate tape (35a) is preferably held by suction by vacuum created by pumping out of air via a plurality of openings (74) with valve openings controllable and distributed appropriately on the ceiling of the upper carriage (72) so that the sucking and blowing pattern across the laminate tape (35a) may be controlled.

[044] Prior to blowing to push the laminate tape (35a) downwardly onto the wafer surface, both the laminate tape (35a) and the wafer (54) should be placed in mutual alignment so that the lamination is precise. Upon release from the vacuum suction means of the upper carriage (72), the laminate tape may be pressed or driven towards the wafer (54) simply by evacuating the ambience within which the lamination is to take place, or if an air-proof chamber is established for the purpose of the lamination, simply evacuating air from the chamber would cause residue air to be sucked in from the upper carriage (72) plurality of openings (74) and thus causing the laminate tape to be pushed downwardly.

[045] There are generally many possible variations of patterns of laying the laminate tape (35a) on the wafer (54) being held on the table (52) simply by controlling the valves of the openings (74). In the following, 2 specific patterns are described as main embodiments from which a skilled person may be able to draw up variations thereof by modifying the sequence of control over the valves of the openings (74).

[046] In the first pattern, as shown in FIGURES 5A - 5D, the openings (74) are configured to provide a release and/or blowing effect at about the centre of the laminate tape (35a) so that the tape is driven downwardly to approach the wafer (54) in a convex manner. The centre of tape will be the initial part of the tape to adhere to the wafer (54) at its corresponding centre. This operation is illustrated in detail in FIG. 5A and FIG. 5B, the upper carriage (72) may be positioned and/or aligned the detached laminate tape (35a) which is held with its adhesive surface exposed (once the release liner is removed) facing downwards against the wafer (54).

[047] Prior to releasing and/or driving the tape, the upper carriage (72) may be lowered to narrow the distance between the upper carriage (72) and the table (52) so that the corresponding distance between the laminate tape (35a) and wafer (54) is narrowed. FIG. 5C illustrates the release and driving of the central portion of the laminate tape (35a) to adhere onto the wafer (54) with the air being blown in and/or alternatively sucked in by the evacuation of the chamber ambient in which the lamination is conducted) via opening (74) at the back of the laminate tape (35a). The upper carriage (72) is also shown withdrawing away from the table (52) so that the laminate tape (35a) is detached in a gradual manner, spreading from the centre to the periphery. The table (52) may also be provided with an outlet (54) through which air may be evacuated from the ambience in which the lamination operation takes place.

[048] The distance between the laminate tape (35a) and wafer (54) and timing between the release of the laminate tape's central portion from the suction action and evacuation of air via outlet (54) are important factors in determining the overall lamination success so that the laminate tape is laid over the wafer (54) in a manner in which less air is trapped between the topographic features of the wafer surface under the tape laminated thereon. FIG. 5D illustrates the direction of spread of the lamination which corresponds with the air movement being suctioned from the chamber via the outlet (56). The laminated wafer may then be returned to its tray in the cassette by the robotic arm and the next wafer taken out to be placed on the table (52) for the next lamination operation while the upper carriage (72) is moved to acquire another pre-cut laminate tape (35) from the tape dispenser (32).

[049] As explained above that the driving force on the laminate tape may be due to the action of airbrushing, i.e. blowing of air from the opening (74) suction or to the suction of air from the chamber or ambience below the laminate tape leading to the tape being driven towards the wafer surface, or a combination of both actions. Accordingly, it is to be understood in this specification that the holding, release or driving of different parts of the tape, such as the periphery of the tape, may also be actuated by such alternative effects of air pressure differential according to the appropriate timing of such effects and the magnitude of the pressure differential.

[050] For example, the laminate tape may be released initially at about the centre but its periphery still held by the vacuum suction means, whereby air blown at about the centre is increased to sufficient force to detach the periphery, and whence, of the whole laminate tape, from the vacuum suction means. The periphery may further be released from the vacuum suction means so that the central air flow blown may be increased to drive the tape downwardly and outwardly so that the entire tape may be laminated onto the wafer. In short, the various patterns of draining air out of chamber or blowing air out of the upper carriage (72) may be operated to be synchronised with a predetermined laminating sequence of the laminate tape over the wafer surface

[051] While it is possible to use laminate tape that comprise a single layer or substrate comprising an adhesive surface on one side and a non-sticky surface on the other, it is preferred that laminate tapes having a separate release liner be used such as the industrially-available back-grinding tapes which are also known by its abbreviation "BG" tapes. The release liner may be detached at a leading edge or periphery of the pre-cut laminate tape. The detached edge is less than 10 mm, preferably not more than 8 mm. The detached edge may then be picked up and held to one part of the tape dispenser so that, when the pre-cut laminate tape (35a) is picked up and held by the upper carriage (72), the upper carriage's (72) movement away from the tape dispenser (32) to move into position above the table and to align with the wafer on the table will thus pull it away from the rest of the release liner and release the entire adhesive surface of the laminate tape (35a) for subsequent lamination.

[052] It would be apparent that the apparatus may be configured in any one of the many ways of aligning the tape to the wafer, i.e. for example, firstly, with all the relevant operations - from dispensing the tape to lamination - being carried within precise movements whereby alignment is automatic and within acceptable tolerances. Secondly, the tape may be dynamically aligned with a static wafer held on the table. Thirdly, the wafer may be dynamically aligned with a static tape held by the upper carriage. Fourthly, both the wafer and the tape may be mutually aligned with each other.

[053] FIGURE 6 shows various elevation views of the laminate tape's laying onto the wafer's topographic features (55), wherein the completely laminated wafer (54) comprises voids (55a) which are substantially vacuum or sub- atmospheric air pressure. Depending on the heat (whether as a by-product of an integrated air drier integrated with our apparatus or purposely directed to the dispensing of the tape), nature of the BG tape, especially its thermoplasticity, and the effect of our vacuum laying operation, the amount of void trapped varies accordingly.

[054] In a second pattern, which may be represented by FIGURE 7, the laminate tape (35a) is released from the upper carriage (72) (not shown) at about one peripheral segment and/or blown to press this segment to laminate thereonto the wafer (54) surface. As the upper carriage moves upwardly away, the air jet may be configured to diverge from that peripheral segment to fan out across the rest of the laminate tape (35a) as it is released from the upper carriage as shown by the direction of arrow (74b). At the same time the outlet (56) may evacuate air from the chamber in the direction shown by arrow (56b) and thus substantially reduce the air from the spaces between the laminate tape (35a) and the wafer (54) surface.

[055] In line with the concept of our invention in taking the advantage of air pressure differential, the laminate tape may be released initially at about one peripheral segment with the fluid medium blown thereat and moved there beyond to detach the remainder of the laminate tape from the vacuum suction means. Alternatively, the laminate tape is released initially at about one peripheral segment with the fluid medium blown thereat, and remainder of said laminate tape is expansively released and wherein the fluid medium is blown correspondingly across said remainder of said laminate tape. It is proposed that the stages of our process to be performed during evacuation or suction of air from the chamber to reduce the pressure therein to about 100 kPa or lower.

[056] Although our drawings show that the table (52) is provided with only one outlet (56), a plurality of outlets may be provided wherein the outlets are distributed around or under the wafer-covered area for more effective evacuation of air from spaces between the laminate tape (35a) and the wafer (54) surface as it blankets over the wafer when air is being evacuated. For example, if an aperture is provided on a part of the wafer which is unfabricated or unpopulated, including the inter-die alleys or junctions, the vacuum effect would be much more effective in reducing air remaining in the void spaces (55a). [057] Similarly, the air flow control means may enable the upper carriage (72) to be operated to provide vacuum suction effect to pick up the laminate tape from the tape dispenser whereby the upper carriage's operation may be controlled to vary and alternate between suction, stop (i.e. non-operating) and reverse (i.e. blowing) operations to control pick up, holding, release and driving of the laminate tape. The upper carriage (72) is configured with a plurality of outlets distributed over a ceiling surface area to be covered by a laminate tape being picked up. During fluid removal, the plurality of outlets may be sequentially opened to enable fluid flow via said outlets to release the laminate tape and drive the lamination onto the wafer (54) according to a predetermined laminating sequence of the wafer surface. Thus, the factors of air pressure differential, time and sequence of the air flow or vacuum suction and the laminating distance are important in the successful lamination of wafers with minimal air trapped in the voids under the tape lamination according to our invention.

[058] In a most preferred embodiment, the vacuum environment within which the lamination occurs, is reduced to an enclosure formed by a 2-part laminating chamber, i.e. an upper half laminating chamber (73) and a lower half laminating chamber (75) as shown and referred to collectively hereinafter in FIGURES 8 to 11. FIGURE 8 provides an overall schematic perspective view of the apparatus wherein an upper carriage (72) is shown to be moving or shuttling between a first position (80a) where a BG or laminating tape may be picked up and a second position (80b) where the tape may be released and laminated upon a wafer surface in vacuum. As this specific embodiment deals with lamination with reference to atmospheric air or absence thereof (i.e. in vacuum), references to "fluid" and "fluid flow" will instead be specific to "air" and "air flow" as the case may be.

[059] The upper carriage (72) is provided with reversible fluid flow control means in the form of tubes (not shown) connected to an air pump and terminate in openings (as previously described in respect of FIG. 5, through the upper carriage (72). The actuation of the air pump will thus create air suction through the openings, which will enable the laminate tape (35a) to be picked up and adhere to the underside of the upper carriage (72). The upper carriage (72) may then move towards the second position (80b) and causes the BG tape (35a) to be detached along its precut lines from the tape (35).

[060] For ease of lowering down to contact and pick up the BG tape and yet provide an air tight closure in form of an upper half chamber, the upper carriage (72) is preferably configured or adapted to be covered over by an upper half laminating chamber (73) as shown in the drawings.

[061] As shown in FIGURE 10, the upper carriage (72) with upper half laminating chamber (73) may be moved to the second position (80b) directly over a table (52) whereupon a wafer (54) to be laminated is placed. The table (52) with wafer (54) may be lowered down into a recess provided in a lower half laminating chamber (75). Both the upper (73) and lower (75) halves of the laminating chamber may mutually close upon each other to form an air-tight enclosure (82) as shown in FIGURE 11. To improve the air tightness between the contacting surfaces of the laminating chamber halves (73, 75), polymeric O- rings (77) may be provided circumferential to the recess on the lower half of the laminating chamber (75).

[062] Telescoping arms (76) may be provided to lower the upper half laminating chamber (73) with the upper carriage down to the wafer (54) on the table (52) which, due to the configuration of the laminating chamber halves (73, 75), simultaneously closes the chamber to form the air-tight enclosure (82). Once the air-tight enclosure is formed, at least a vacuum pump may be activated to remove air from the enclosure (82). During this air evacuation period, the reversible fluid flow control means that is being used to hold the BG tape by suction action may be maintained to keep hold onto the BG tape. When the pressure in the air-tight enclosure (82) has dropped to a predetermined level, the reversible fluid flow control means may be stopped to stop the suction action and allow the BG tape to be released and laid onto the semiconductor wafer surface.

[063] As a preferred embodiment, apart from stopping the reversible fluid flow control means to halt the suction on the BG tape (35a), as the tape is released to be laid onto the wafer surface, the fluid flow control means may reverse the air flow so that, instead of sucking, air flow is blown against the back of the BG tape to gently press the BG tape's adhesive surface against the wafer's corresponding surface. As in the case of the previous embodiment described in FIGS. 5 and 7, there may be 2 or more different patterns of providing the air flows to gentle roll the BG tape against the wafer surface.

[064] In the first pattern, air flow is reversed so that the fluid flow control means blows air jets at about the central portion of the BG tape (35a) to press the tape's adhesive surface against the wafer's corresponding surface. Next, the air jets are further blown to fan out radially from said central portion to the periphery of said laminate tape thereby pressing said laminate tape's adhesive surface over said wafer's corresponding surface to complete the rolling over the entire tape surface. In the second pattern, air jets are blown at about one peripheral segment of the laminate tape to press the tape's adhesive surface at that segment against the wafer's corresponding surface. The air jets are then further blown divergent from the peripheral segment to fan across the rest of the laminate tape thereby pressing the tape's adhesive surface beyond said peripheral segment over and across the rest of the wafer's corresponding surface.

[065] Although our present has been described with specific reference to 2 patterns of airbrushing and/or vacuum suction which have been described in detail above, many variations of these patterns may be improvised or modified without departing from the general principles of our invention's method. Similarly, while our apparatus according to our invention have been described in respect of the 3 principal components, namely the tape dispenser, the upper carriage and the table, it is obvious to a skilled person that each of these component's parts may be modified, alternatively reconfigured, or adapted accordingly to achieve the same or similar results or specific preferred features. These substitutes, equivalents, modifications, adaptations, reconfigurations or alternative embodiments which are not specifically described herein are nevertheless to be considered as falling within the scope and intent of the following claims.

Claims

CLAIMSWhat Is Claimed Is:

1. A method for laminating a semiconductor wafer surface with bumped topography in a substantially fluid-proof ambience, the method comprising the steps of:

(a) pre-cutting a laminate tape comprising at least an adhesive surface suitable for backgrinding protection to substantially cover said wafer's planar shape or outline; (b) picking said laminate tape by vacuum suction means at a substantially planar orientation with said laminate tape's adhesive surface facing said wafer surface to be laminated;

(c) placing said laminate tape over said wafer in mutual outline alignment;

(d) releasing said laminate tape from said vacuum suction means; (e) blowing a fluid medium at about central portion of said laminate tape to press said laminate tape's adhesive surface thereat against said wafer's corresponding surface,

2. A method for laminating a semiconductor wafer surface with bumped topography in a substantially fluid-proof ambience, the method comprising the steps of:

(a) pre-cutting a laminate tape comprising at least an adhesive surface suitable for backgrinding protection to substantially cover said wafer's planar shape or outline;

(b) holding said laminate tape by vacuum suction means in a substantially planar orientation with said laminate tape's adhesive surface facing said wafer surface to be laminated; (c) placing said laminate tape and said wafer in mutual outline alignment;

(d) releasing said laminate tape from said vacuum suction means;

(e) blowing a fluid medium at about one peripheral segment of said laminate tape, pressing said laminate tape's adhesive surface thereat against said wafer's corresponding surface, (T) further blowing said fluid medium to diverge from said peripheral segment to fan across said laminate tape thereby pressing said laminate tape's adhesive surface beyond said peripheral segment over and across said wafer's corresponding surface;

3. A method for laminating a semiconductor wafer according to any one of Claims 1 and 2 wherein the laminate tape further comprising a release liner covering the adhesive surface, and wherein said release liner is removed to expose said adhesive surface prior to lamination.

4. A method for laminating a semiconductor wafer according to Claim 3 wherein a leading edge of the release liner is first detached and the rest of the liner is removed when the laminate tape is picked up and moved into alignment with said wafer.

5. A method for laminating a semiconductor wafer according to Claim 4 wherein the leading edge detached is less than 10 mm.

6. A method for laminating a semiconductor wafer according to any one of Claims 1 and 2 wherein the wafer is placed in alignment with the laminate tape.

7. A method for laminating a semiconductor wafer according to any one of Claims 1 and 2 wherein the laminate tape is placed in alignment with the wafer.

8. A method for laminating a semiconductor wafer according to Claim 1 wherein the laminate tape is released initially at about the centre with the periphery still held by the vacuum suction means.

9. A method for laminating a semiconductor wafer according to Claim 8 wherein the fluid medium that is blown at about the centre of the laminate tape is increased to sufficient force to detach the periphery, and whence, of the whole laminate tape, from the vacuum suction means.

10. A method for laminating a semiconductor wafer according to Claim 8 wherein the periphery is further released from the vacuum suction means.

11. A method for laminating a semiconductor wafer according to Claim 2 wherein the laminate tape is released initially at about one peripheral segment with the fluid medium blown thereat and moved there beyond to detach the remainder of the laminate tape from the vacuum suction means.

12. A method for laminating a semiconductor wafer according to Claim 2 wherein the laminate tape is released initially at about one peripheral segment with the fluid medium blown thereat, and remainder of said laminate tape is expansively released and wherein the fluid medium is blown correspondingly across said remainder of said laminate tape.

13. A method for laminating a semiconductor wafer according to any one of Claims 1 - 12 wherein the blowing is the effect of residue air being sucked out from parts of the fluid-proof ambience.

14. A method for laminating a semiconductor wafer surface with bumped topography in a substantially fluid-proof ambience, the method comprising the steps of: (i) pre-cutting a laminate tape comprising at least an adhesive surface suitable for backgrinding protection to substantially cover said wafer's planar shape or outline;

(ii) picking said laminate tape by vacuum suction means at a substantially planar orientation with said laminate tape's adhesive surface facing said wafer surface to be laminated; (iii) placing said laminate tape over said wafer in mutual outline alignment in a substantially vacuum environment;

(iv) releasing said laminate tape from said vacuum suction means; and (v) blowing a fluid medium to press said laminate tape's adhesive surface against said wafer's corresponding surface.

15. A method for laminating a semiconductor wafer surface according to Claim 14 wherein step (v) comprises: (a) blowing a fluid medium at about central portion of said laminate tape to press said laminate tape's adhesive surface thereat against said wafer's corresponding surface; and (b) further blowing said fluid medium to fan out radially from said central portion to the periphery of said laminate tape thereby pressing said laminate tape's adhesive surface over said wafer's corresponding surface.

16. A method for laminating a semiconductor wafer surface according to Claim 14 wherein step (v) comprises: (a) blowing a fluid medium at about one peripheral segment of said laminate tape, pressing said laminate tape's adhesive surface thereat against said wafer's corresponding surface,

(b) further blowing said fluid medium to diverge from said peripheral segment to fan across said laminate tape thereby pressing said laminate tape's adhesive surface beyond said peripheral segment over and across said wafer's corresponding surface;

17. An apparatus for laminating a semiconductor wafer with bumped topography in a substantially fluid-proof ambience, comprising: a table (52) adapted to hold a semiconductor wafer (54) to be laminated; an upper carriage (72) movable between a first position at which a laminate tape may be picked up, and a second position at which said laminate tape is releasable to laminate said semiconductor wafer (54); said upper carriage (72) is provided with reversible fluid flow control means for picking up and releasing said laminate tape; a tape dispenser (32) wherein laminate tapes are dispensable therefrom for picking up by said upper carriage (72); wherein at least the table and upper carriage (72) are disposed in a fluid- proof chamber and provided with means for controlling fluid flow thereinto.

18. An apparatus for laminating a semiconductor wafer according to Claim 17 wherein the table is provided with a plurality of outlets distributed at least at one of under and around the wafer-covering area for the removal of fluid via said outlets by the fluid-evacuating means.

19. An apparatus for laminating a semiconductor wafer according to Claim 18 wherein the table is provided with at least an outlet provided at a position to be covered by a wafer with an aperture at an unfabricated part, including at any one of unpopulated part, inter-die alleys or junction of the wafer, through which fluid may be drain out.

20. An apparatus for laminating a semiconductor wafer according to any one of Claims 18 and 19 wherein the fluid draining out of the outlets is operated to be synchronised with a predetermined laminating sequence of the laminate tape over the wafer surface.

21. An apparatus for laminating a semiconductor wafer according to Claim 17 wherein the tape dispenser dispenses laminate tape which adhesive surface is covered by a release liner.

22. An apparatus for laminating a semiconductor wafer according to Claim 17 wherein the laminate tape dispensed is pre-cut to substantially cover the semiconductor wafer.

23. An apparatus for laminating a semiconductor wafer according to Claim 17 wherein a leading edge of the release liner is first detached by the tape dispenser and the rest of the release liner is detached as the upper carriage (72) picks and holds the laminate tape and moves from the first position to the second position.

24. An apparatus for laminating a semiconductor wafer according to Claim 23 wherein the leading edge detached is less than 10 mm.

25. An apparatus for laminating a semiconductor wafer according to Claim 17 wherein the fluid flow control means enables the upper carriage (72) to be operated to provide vacuum suction effect to pick up the laminate tape from the tape dispenser.

26. An apparatus for laminating a semiconductor wafer according to Claim 25 wherein the fluid flow control means enables the upper carriage (72)'s operation to be controlled to vary and alternate between suction, stop (i.e. non- operating) and reverse (i.e. blowing) operations to control pick up, holding, release and driving of the laminate tape.

27. An apparatus for laminating a semiconductor wafer according to any one of Claims 25 and 26 wherein the upper carriage (72) is configured with a plurality of outlets distributed over a ceiling surface area to be covered by a laminate tape being picked up.

28. An apparatus for laminating a semiconductor wafer according to Claim

27 wherein, during fluid removal, the plurality of outlets are sequentially opened to enable fluid flow via said outlets to release the laminate tape and drive the lamination onto the wafer according to a predetermined laminating sequence of the wafer surface.

29. An apparatus for laminating a semiconductor wafer according to Claim

28 wherein fluid is allowed to be drawn in initially at about central portion of the laminate tape thereby releasing and driving the central portion of said laminate tape to laminate onto corresponding portion of the wafer, and thence fan out to the rest of the tape to laminate completely onto the wafer.

30. An apparatus for laminating a semiconductor wafer according to any one of Claims 17 -19 wherein the fluid is allowed to be drawn in initially at about one peripheral segment of said laminate tape, pressing said laminate tape's adhesive surface thereat against said wafer's corresponding surface, and thence, drawing the fluid to laminate said tape across said wafer's entire corresponding surface.

31. An apparatus for laminating a semiconductor wafer with bumped topography in a substantially fluid-proof ambience, comprising: a tape dispenser (32) from which laminate tapes (35a) are dispensable; a table (52) upon which a semiconductor wafer (54) to be laminated with a laminate tape (35a) may be placed, said table (52) being adaptably disposed within a recess of a lower half laminating chamber (75); and an upper carriage (72) movable between a first position (80a) at which a laminate tape (35a) may be picked up from said tape dispenser (32), and a second position (80b) at which said laminate tape (35a) may be released to laminate said semiconductor wafer (54); wherein said upper carriage (72) is provided with reversible fluid flow control means for suction pick up and release of said laminate tape

(35a) therefrom, and said upper carriage (72) is adapted with an upper half laminating chamber (73) such that, in said second position (80b), said upper half laminating chamber (73) and said lower half laminating chamber (75) may be closed to form a fluid-proof enclosure within which said laminating tape (35a) may be released from the table (52) to laminate said wafer (54).

32. An apparatus according to Claim 31 wherein fluid flow control means removes fluid from the fluid proof enclosure prior to laminating the wafer.

33. An apparatus according to Claim 32 wherein the upper carriage's (73) reversible fluid flow control means is operated to stop the suction and release the laminate tape (35a) onto the wafer (54).

34. An apparatus according to Claim 33 wherein the reversible fluid flow control means is further operated to blow a fluid medium to press said laminate tape's adhesive surface against said wafer's corresponding surface.

35. An apparatus according to Claim 34 wherein the fluid medium is blown at about central portion of said laminate tape (35a) to press said laminate tape's adhesive surface thereat against said wafer's corresponding surface, and further blowing said fluid medium to fan out radially from said central portion to the periphery of said laminate tape thereby pressing said laminate tape's adhesive surface over said wafer's corresponding surface.

36. An apparatus according to Claim 34 wherein the fluid medium is blown at about one peripheral segment of said laminate tape to press said laminate tape's adhesive surface thereat against said wafer's corresponding surface, and further blowing said fluid medium to diverge from said peripheral segment to fan across said laminate tape thereby pressing said laminate tape's adhesive surface beyond said peripheral segment over and across said wafer's corresponding surface;

37. An apparatus for laminating a semiconductor wafer according to any one of Claims 17 - 36 wherein a method according to any one of Claims 1 - 16 is implemented.

38. A semiconductor wafer laminated by a method according to any one of Claims 1 -16.

39. A semiconductor wafer laminated with an apparatus according to any one of Claims 17 -36.

40. A semiconductor device, including die or package, processed by a method according to any one of Claims 1 -16.

41. A semiconductor device, including die or package, processed with an apparatus according to any one of Claims 17 -36.

42. An appliance installed with a semiconductor device processed according to any one of Claims 40 - 41.