Semiconductor sawing method and system

Abstract

Semiconductor sawing methods and systems are disclosed. In one example, a method of manufacturing an integrated circuit includes a method for dicing a semiconductor wafer (302), the method including disposing the semiconductor wafer (302) on a moveable dicing table (312), dicing the semiconductor wafer (302), and at least during dicing the semiconductor wafer (302), spraying a cleaning fluid (320) across an exposed side (318) of the semiconductor wafer (302), wherein the cleaning fluid (320) completely covers the semiconductor wafer (302). The spraying of the cleaning fluid (302) is sprayed to form a fluid layer or film that cleans or reduces other fluids from the exposed side (318) of the semiconductor wafer (302). Other aspects are also presented.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to semiconductor devices and fabrication, and more particularly to methods and systems for sawing semiconductor wafers. BACKGROUND

[0002] Semiconductor devices are used in many applications. During the fabrication of semiconductor devices, one step involves wafer dicing. Wafer dicing is the process of cutting a semiconductor wafer into separate individual dies or pieces that are assembled on the wafer. The wafer is typically placed and secured or mounted horizontally on top of a dicing table. A wafer frame is used to support the wafer, which is usually placed on a tape having an adhesive surface on one side that holds the wafer during sawing. A sawing apparatus including a spindle assembly for manipulating a rotating circular blade is positioned on top of the secured wafer. For this purpose, the wafer is sawn into individual dies by cutting along pre-defined sawing lanes on the wafer. SUMMARY

[0003] According to one aspect, a method of fabricating integrated circuits includes sawing a semiconductor wafer, attaching a plurality of dies to a plurality of lead frames, interconnecting each of the plurality of dies to a corresponding one of the plurality of lead frames, and applying a mold compound over at least a portion of any dies on the lead frames and at least a portion of the lead frames for each of the lead frames. Sawing the semiconductor wafer includes providing a dicing table, securing the semiconductor wafer in a sawing position, and applying a rotating sawing blade to the wafer secured in the sawing position to cut the wafer into a plurality of separate dies. Sawing the semiconductor wafer also includes applying a first fluid for cooling to the semiconductor wafer at a location proximate to where the rotating sawing blade contacts the semiconductor wafer, and applying a second fluid to substantially all of an exposed side of the semiconductor wafer. Applying the second fluid includes using a fluid jetting element proximate to and coupled to the dicing table. The fluid jetting element is positioned proximate to an edge of the semiconductor wafer to jet the second fluid through substantially all of the exposed side of the semiconductor wafer and substantially parallel to the exposed side when the semiconductor wafer is mounted in the sawing position.

[0004] According to one aspect, a method of manufacturing integrated circuits includes sawing a semiconductor wafer into separate dies along one or more streets formed on the semiconductor wafer, attaching a plurality of dies to a plurality of lead frames, interconnecting each of the plurality of dies to a corresponding lead frame of the plurality of lead frames, and applying a molding compound over at least a portion of any dies on the lead frames and over at least a portion of the lead frames for each of the lead frames. The aspect of sawing the semiconductor wafer into separate dies includes cutting the semiconductor wafer along the one or more streets to form the plurality of dies, where the semiconductor wafer has a first side and a second side, and where the first side is exposed. The aspect of sawing the semiconductor wafer into separate dies also includes applying a first fluid for cooling proximate to where the semiconductor wafer is cut, and spraying (at least during sawing) a second fluid or a cleaning fluid through substantially all of the first side of the semiconductor wafer in the form of a fluid layer to remove any of the first fluid that would otherwise reside on the first side of the semiconductor wafer.

[0005] According to one aspect, a method for dicing a semiconductor wafer into separate dies includes mounting the semiconductor wafer on a moveable cutting table, cutting the semiconductor wafer, and spraying a cleaning fluid through an exposed side of the semiconductor wafer at least during cutting, where the cleaning fluid completely covers the semiconductor wafer. Completely covers means that at least 90% of the exposed side has the cleaning fluid moving through the exposed side. Spraying the cleaning fluid is a fluid that removes any other liquid that resides on the exposed side of the semiconductor wafer. Spraying the cleaning fluid includes substantially forming a layer of the cleaning fluid that substantially parallels a plane of the exposed side of the semiconductor wafer across the semiconductor wafer to remove any fluid, such as a cooling fluid, on the exposed side of the semiconductor wafer.

[0006] According to one aspect, a system for sawing a semiconductor wafer includes a moveable cutting table for receiving a semiconductor wafer and having a sawing configuration, a dicing saw associated with the cutting table for cutting the semiconductor wafer, and a fluid sprayer element coupled to the moveable table. The fluid sprayer element includes a plurality of nozzles configured to produce a fluid layer through the semiconductor wafer and provide complete coverage. Other aspects are disclosed herein. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a schematic perspective view of an illustrative system for sawing a semiconductor wafer including a fluid sprayer element;

[0008] Figure 2 is a schematic perspective view of a portion of an illustrative system for sawing a semiconductor wafer including a fluid sprayer element;

[0009] Figure 3is an elevational view schematic of a portion of an illustrative system for sawing semiconductor wafers including a fluid jetor element;

[0010] Figure 4 is an elevational view schematic of a portion of an illustrative system for sawing semiconductor wafers including a fluid jetor element;

[0011] Figure 5 is an elevational view schematic of an illustrative cutting table and fluid jetor element;

[0012] Figure 6 is an elevational view schematic of an illustrative cutting table and fluid jetor element;

[0013] Figure 7 is an elevational view schematic of an illustrative cutting table and fluid jetor element;

[0014] Figure 8 is a flowchart of an illustrative method for dicing a semiconductor wafer into separate dies. DETAILED DESCRIPTION

[0015] Wafer dicing is the process of cutting a semiconductor wafer into separate individual microelectronic chips or dice that are assembled on the wafer. The wafer is typically placed and secured or mounted horizontally on top of a cutting table. A wafer frame is used to support the wafer, which is typically placed on a tape having an adhesive surface on one side that holds the wafer during sawing. A sawing apparatus including a spindle assembly for manipulating a rotating or spinning circular blade is positioned on top of the secured wafer. The wafer is sawn into individual dies by cutting along pre-defined saw streets on the wafer.

[0016] Water nozzles can be used to spray the wafer during the sawing process at the cutting location. This wet environment can cause problems. Sometimes, aluminum can be used with thin film metallization for contacting silicon and forming interconnect lines on integrated circuits. To address electromigration problems, copper can be added to the aluminum to form an alloy. The copper content can vary, for example, from 0.5% to 4.5% by weight in one application. With the use of aluminum copper (Al-Cu) alloys, the sensitivity of the film to corrosion increases during wafer fabrication and post wafer fabrication assembly. In a wet cutting environment, three types of corrosion are known: galvanic or hetero-metal cell, concentration cell, and electrolytic cell. Corrosion requires two electrodes, an interconnect solution, and a driving force.

[0017] Wet cutting environments promote corrosion and are a problem when the semiconductor wafer contains copper. For example, in the fabrication of integrated circuits (ICs) with bond-on-active-circuit (BOAC), without addressing the resident water, higher than desired failure rates can result in the form of non-stick pad (NSOP) bonds on the pads. This is due to the galvanic bond pad corrosion of the BOAC. The corrosion is caused by the electroplating of copper oxide particles on the Pmoat bond pad, resulting in NSOP errors at the wire bond site.

[0018] Without being limited by theory, during sawing, copper ions enter the sawing water and deposit onto the cathodic bond pads, caused by the electrochemical potential difference between the adjacent P-moat and N-moat pads. Once the copper deposits on the palladium, it is oxidized causing corrosion. The sawing water provides an interconnect ion solution, which allows the redox reactions to occur.

[0019] For a wafer with Pd, Ni, Cu to BOAC connections on the chip, the reactions are as follows. On the P-moat side, it will be:

[0020] CU + + 1 e - → Cu 0

[0021] 2H + + 2 e - → H2

[0022] O2+ 4H + + 4 e - → H2O

[0023] On the N-moat side, it will be:

[0024] CU 0 → CU + + 1 e -

[0025] CU2O → 2CU + + 2 e - + ½ O2

[0026] CU2O → 2CU + + O 2-

[0027] The method of reducing resident water presented in the methods and systems herein apply to wafers without copper, but copper is a prominent consideration.

[0028] It has been observed that one factor that causes corrosion is the time that the wafer is exposed to the resident or stationary water on the wafer. In order to solve this problem, a continuous water flow through the wafer is formed to prevent the formation of a collection or resident water collection on the top or exposed side of the wafer. Therefore, in one aspect, a method for dicing a semiconductor wafer into separate tube cores is provided, which includes mounting the semiconductor wafer on a movable cutting table, cutting the semiconductor wafer, and at least during cutting the semiconductor wafer, spraying a cleaning fluid through the exposed side of the semiconductor wafer, wherein the cleaning fluid completely covers the semiconductor wafer. The injection of the cleaning fluid is any time that other fluids (cooling and lubrication) are being injected or at least during cutting. The cleaning fluid injection occurs during cutting and can stop or pause the cleaning fluid injection when cutting stops or pauses. After cutting, the cleaning fluid injection is stopped.

[0029] Referring now to the drawings and first to Figure 1 , a system 100 for sawing a semiconductor wafer 102 includes a movable cutting table 104 for receiving the semiconductor wafer 102. The semiconductor wafer 102 can be placed in a cutting position by holding the wafer 102 on a wafer frame 105 using tape 103, and then mounting or securing the semiconductor wafer on the movable cutting table 104, for example, by vacuum. The semiconductor wafer 102 can take many forms. In one example, the semiconductor wafer 102 includes copper. In one example, the semiconductor wafer 102 includes a plurality of integrated circuits, wherein the plurality of integrated circuits have a bonding layer on the active circuit, and the semiconductor wafer 102 also includes copper.

[0030] The movable cutting table 104 has a sawing configuration. A dicing saw or saw 106 is associated with the cutting table 104 for dicing semiconductor wafers. The movable cutting table 104 moves in a plane defined by an x-axis 108 and a z-axis 110. The dicing saw 106 moves in a vertical or y-axis 112 and in the z-axis 110.

[0031] The fluid ejector element 114 is coupled to the movable cutting table 104. The fluid ejector element 114 may be attached to the movable cutting table 104 by an attachment arm 116 or a mounting block (see, e.g., Figure 5 The fluid ejector element 114 ejects the cleaning fluid across the first exposed surface 118 or exposed side of the semiconductor wafer 102 from a first edge 120 of the movable cutting table 104 to a second edge 122 of the movable cutting table 104. As used herein, "exposed side" refers to the upward facing side of the semiconductor wafer 102. Figure 1The side of the orientation shown, and which is on the opposite side of the wafer from the side supported by and against the moveable dicing table 104. The cleaning fluid ejected by the fluid ejector element 114 is in the direction shown by reference arrow 124. Ejecting the cleaning fluid forms a fluid film or fluid layer that removes any resident liquid fluid, for example, resident liquid fluid 126, from the first exposed side 118. Figure 1 The system 100 is shown with the fluid ejector element 114 not ejecting fluid, in order to show one example of resident liquid fluid that would exist without the fluid ejector element 114 running.

[0032] The resident liquid fluid 126 comes from other fluids used in the dicing process. The dicing or cutting saw 106 includes a cutting blade 128, for example, a diamond-coated abrasive wheel, on a spindle 130 that can spin or rotate at high revolutions per minute. The dicing saw 106 can include various components that will be understood by those skilled in the art, for example, detection, alignment, and transfer devices, which are not further described. A first nozzle 132 can eject fluid 134 for cooling or lubrication. A second nozzle 136 or a third nozzle 138 can eject fluid 140 for removing silicon dust or debris from the cutting or cooling fluid or lubrication. Fluid delivered by the various nozzles 132, 136, 138 coupled to the dicing saw 106 can form the resident liquid fluid 126 on the first side 118 of the wafer. In addition, the resident liquid fluid 126 promotes corrosion and is addressed herein by the fluid ejector element 114.

[0033] The fluid film or layer is created by the fluid ejector element 114, which can be coupled to an external wafer dicing table. It moves with the table 104 and ejects cleaning fluid to push the resident fluid 126 to move, thereby avoiding resident liquid fluid on the wafer 102. The fluid ejector element 114 ejects fluid in a pattern that creates a fluid film or a complete covering fluid layer or fluid wall through (e.g., substantially parallel to) the exposed surface 118 of the semiconductor wafer 102 to remove any resident water 126 that would otherwise pool or collect on the exposed surface 118 of the semiconductor wafer 102. The cleaning fluid from the fluid ejector element 114 contacts any cooling / lubrication fluid sprayed from the other nozzles and removes the cooling / lubrication fluid from the exposed side 118 of the semiconductor wafer 102. In addition, this eliminates or reduces any resident liquid fluid, for example, water from the other nozzles that can promote corrosion.

[0034] The fluid ejector element 114 can include a plurality of nozzles (see, for example Figure 2 216 in FIG. 2, Figure 3 322 in FIG. 3, Figure 4 417 in FIG. 4, Figure 5 520 in FIG. 5, Figure 7702 in FIG), which is configured to generate a fluid layer that passes through the semiconductor wafer 102 and provides complete coverage. Complete coverage helps avoid residual resident liquid fluid 126. By ejecting fluid from the fluid ejector element 114 during dicing, fluid from the nozzles 132, 136, and 138 is removed from the first surface 118 of the wafer 102, thereby reducing or eliminating resident liquid fluid 126. When the dicing process is complete or if the dicing process is paused, ejection from the fluid ejector element 114 can be stopped.

[0035] The fluid ejector element 114 can be coupled to a lock on a portion of the cutting table 104, as will be described in other embodiments. The fluid ejector element 114 is coupled a distance from the outer edge of the cutting table 104 (from the first edge 120). The distance can be between 5 and 100 mm or some other dimension. In one exemplary arrangement, the fluid ejector element 114 is greater than 35 mm from the edge of the cutting table (see, for example, FIG. 1 ). Figure 4 In one exemplary arrangement, the fluid ejector element 114 is approximately 46 mm from the edge of the cutting table (see, e.g., Figure 4 In one exemplary arrangement, the fluid ejector elements 114 have a coverage area of ​​approximately 400 mm in the xz plane, for illustrative application to a full 300 mm wafer. The fluid layer or film formed by the collective ejection of the fluid ejector elements 114 passes through the wafer 102 and can impinge on a portion of the fluid collection portion of the system 100. This is Figure 2 Clearly presented in.

[0036] refer to Figure 2 , presents an illustrative system 200 for sawing a semiconductor wafer 202 (similar to Figure 1 1. The system 200 includes a rotating saw blade 204 on a spindle 206. The semiconductor wafer 202 is supported and moved by a movable stage (not explicitly shown to more clearly illustrate other aspects, but similar to Figure 1The nozzles 208 spray a cooling or lubricating fluid 210. Fluid jetting elements 212 are offset from the table and thus from the semiconductor wafer 202 and jet a cleaning fluid 214. The fluid jetting elements 212 include a plurality of nozzles 216. In this illustrative arrangement, the cleaning fluid 214 jetted by the plurality of nozzles 216 of the fluid jetting elements 212 together form a layer or film 218 that is sprayed over the entire wafer 202. The cleaning fluid pressure and the plurality of nozzles 216 allow the layer or film of fluid to be shot through the exposed surface of the wafer in a manner that contacts or just above the wafer to impinge on any resident water from other aspects of the operation and remove the resident water due to the force of the cleaning fluid. In this manner, no or a reduced amount of resident fluid remains on the exposed surface or first surface 220 of the wafer 202. In Figure 3 The layer or film nature of the jetted cleaning fluid can be clearly seen in the illustrative example. While shown as nearly ideal straight lines, it should be understood that some changes in the flow will occur, but the cleaning fluid layer will be delivered that will remove any fluid that would otherwise remain on the exposed surface 220 as resident liquid.

[0037] Reference is now made to Figure 3 A front view schematic of a portion of an illustrative system 300 for sawing a semiconductor wafer 302 including fluid jetting elements 304 is presented. The system 300 includes a cutting saw 303 having a cutting blade 306 on a spindle 308 that is rotated or spun at high revolutions per minute (rpm) to cut the wafer 302. The wafer 302 is mounted to a frame 310 with a tape 311 and is mounted on a movable table 312. A plurality of cooling or lubricating nozzles 314 are coupled to the cutting saw 303 and spray a first fluid 316 onto a first side 318 of the wafer 302 to cool or lubricate the wafer during cutting. In addition, the fluid 316 can pool or collect on the first side 318 without restraint, but the cleaning fluid 320 jetted from the fluid jetting elements 304 removes or pushes the first fluid 316 away from the first side 318.

[0038] The cleaning fluid 320 can take a variety of forms. In one example, the cleaning fluid 320 is deionized water (DIW). Other fluids can be used, such as air. The DIW is typically passed through a CO2 bubbler to mix CO2 into it to control the resistivity of the water. The cleaning fluid 320 is sprayed at a rate to go from one end 324 to the other end 326 of the wafer 302 or from one end of the table to the other. The rate varies with the nozzle spec, the size of the wafer 302, and the distance from the edge of the table to where the wafer 302 is located. In one example, the flow rate is between 4 and 8 liters per minute, and in one example is approximately 6 L / min. If a weaker flow rate is used, the coverage distance can be less. Sufficient pressure is needed to spray the cleaning fluid 320 through the wafer 302 and provide full coverage. The spraying occurs each time the cutting process occurs.

[0039] The fluid sprayer element 304 includes a plurality of nozzles 322, but only one is visible in this view because the fluid sprayer element 304 is straight in this example and not arcuate as in the previous examples. The arcuate shape (see fluid sprayer elements 114, 212) helps to maintain a similar distance from the fluid sprayer element to the movable table to ensure good coverage, but other shapes can be used, such as the straight shape shown. Figure 3

[0040] Reference is now made primarily to Figure 4 which is a schematic perspective view of a portion of an illustrative system 400 for sawing a semiconductor wafer (not shown in this example for clarity of other parts but similar to the wafers 102, 202, 302) that includes a fluid sprayer element 402. The system 400 includes a cutting saw 404 that has a cutting blade 406 on a rotating or turning spindle 408. The cutting saw 404 moves the cutting blade 406 toward a cutting table 410. The cutting table 410 has an outer edge 412 on one end 414 of the mounting portion.

[0041] The fluid sprayer element 402 is coupled to the cutting table and placed a distance 416 in the x-z plane from the outer edge 412 of the mounting portion. The fluid sprayer element 402 in this embodiment is arcuate and has a plurality of nozzles 417.

[0042] The cutting saw 404 also includes a plurality of nozzles that are coupled to or form a part of and move with the cutting saw 404. The cutting saw 404 includes a first blade cooling nozzle 418, a second blade cooling nozzle 420, a first cleaning nozzle 422, and a second cleaning nozzle 424. The various nozzles 418, 420, 422, 424 can leave liquid resident or more liquid resident, but the fluid sprayer element 402 sprays a layer or film (not shown but similar to the layer or film 314) of cleaning fluid that covers the nozzles 418, 420, 422, 424 and the cutting blade 406.​Figure 3

[0043] Referring now primarily to Figure 5 , an illustrative perspective view of an example moveable dicing table 500 and fluid jet element 502 is shown. The dicing table 500 has a mounting portion 504 that can include vacuum holes for holding a semiconductor wafer (see, e.g., 302) to the dicing table 500. The dicing table 500 includes a support member 506 for supporting a tape frame (see, e.g., 105). The moveable dicing table 500 moves the mounting portion 504 (not shown, but see, e.g., 404) as needed for dicing by a dicing saw. The mounting portion 504 is located on a platform 508.

[0044] The fluid jet element 502 is mounted to the dicing table by one or more mounting locks 510 that are coupled to a mounting block 512 that is coupled to the fluid jet element 502. One or more fasteners 514 can couple the mounting lock 510 to the platform 508 or another portion of the table 500. Likewise, one or more fasteners 516 can couple the fluid jet element 502 to the mounting lock 510 or directly to the platform 508. A fluid line 518 provides cleaning fluid to the fluid jet element 502. A plurality of nozzle or channel nozzles 520 are included as an aspect of the fluid jet element 502 and are aimed toward the mounting portion 504 of the table 500. In this example, the fluid jet element 502 is arcuate and has the same center of curvature as the table 500.

[0045] Referring now primarily to Figure 6 , an illustrative plan view of a semiconductor wafer 600 on an illustrative dicing table is shown with a fluid jet element 602 jetting cleaning fluid 604 through the semiconductor wafer 600. The wafer 600 has a radius 606. The fluid jet element 602 is arcuate and has an 608. The angle of overlap is such that full coverage of the cleaning fluid 604 through the wafer 600 is provided.

[0046] Referring now primarily to Figure 7 , an illustrative perspective view of a portion of an illustrative fluid jet element 700 is shown. In this example, the fluid jet element 700 is a plastic member or arcuate housing 701 that has a plurality of nozzles 702 formed as holes 704. The spacing distance of the spacing 706 between the holes 704 can vary as needed to provide a full fluid layer or film when jetted and flowing at working pressures. In one illustrative example, the nozzle spacing 706 is between 2 and 8 mm. In another example, the nozzle spacing is 4 mm. In another example, a small track or channel of jetted fluid layer is provided.

[0047] Referring now primarily to​Figure 8 which presents a flowchart 800 of an illustrative method for dicing a semiconductor wafer into separate dies or pieces. The process begins 802 with mounting a semiconductor wafer on a moveable dicing table. The wafer is cut 804 using a dicing saw while a cleaning fluid is sprayed 806 through the exposed surface of the wafer in a sheet or film manner to remove or reduce the fluid of resident liquid that would otherwise collect or pool in greater amounts. This helps to reduce corrosion and the failures that can accompany corrosion.

[0048] In one illustrative process, a semiconductor wafer is placed on a dicing table and a pre-defined saw street is located using wafer pattern alignment. The saw blade spindle is rotated while water is applied for cooling or lubrication. The blade cuts in the y-axis direction while the table moves the wafer on the pre-defined saw street and then moves in the z-axis on another pre-defined saw street. The dicing table moves back and forth in the plane to cause the wafer to be cut along the desired path. A nozzle wets the wafer along the pre-defined saw street. During the cutting, a cleaning water film or sheet is applied that is parallel to the plane of the exposed surface of the wafer and is sprayed close to the surface so that any fluid from other nozzles is forced off the wafer. After the cutting is complete, the wafer is transferred to a cleaning table for overall cleaning and drying.

[0049] As used herein, "substantially all of the exposed side of the semiconductor wafer" means at least 90% of the exposed side of the wafer. "Substantially parallel" as used herein means within 10 degrees.

[0050] A semiconductor dicing process or wafer dicing is one aspect of an integrated circuit ("IC") manufacturing process. The wafer can be thinned prior to dicing. The wafer is mounted with its active surface exposed. The mounting uses a release tape that is fixed to a frame. The wafer is then diced or cut into pieces as discussed herein. The dicing machine or cutting station uses a program to drive the dicing blade down the saw street at a defined spindle speed, depth, and dicing rate to separate the wafer into individual dies.

[0051] Each of the separated dies undergoes a bonding or interconnection process. The separated dies are typically pulled off the releasable tape and mounted onto a carrier frame or lead frame. The dies are oriented and a die attach machine adheres the dies to the frame. The dies can be cured to the frame and wire bonding is then completed. The bonding electrically couples the dies to the lead frame.

[0052] After wire bonding or interconnection, a molding compound is applied to cover some or all of the components of the integrated circuit. The leads can then be finished using a lead finishing process to prepare or enhance the leads. According to the process, the parts on the lead frame can be marked and these packages can be singulated from a strip. Straight, gull wing, or J-shaped curved leads or pins are formed. The integrated circuits can then be inspected and prepared for shipment.

[0053] In various arrangements presented, once a semiconductor wafer is cut, the semiconductor wafer is removed from the cutting station and a fine cleaning process is performed on the wafer. The semiconductor wafer is moved from the cutting table to a cleaning table. The cleaning at the cleaning table is different than the fluid that maintains a resident liquid from the exposed side of the semiconductor wafer during the cutting process on the cutting table. The cleaning fluid helps to avoid the resident liquid, but also helps to displace or remove silicon dust or powder as it is cut.

[0054] The nozzles (see, e.g. Figure 2 216 in FIG. 2, Figure 3 322 in FIG. 3, Figure 4 417 in FIG. 4, Figure 5 520 in FIG. 5, Figure 7 702 in FIG. 7) spray or spurt the cleaning fluid to form a fluid layer or film or curtain of liquid that passes over the exposed side of the semiconductor wafer with enough force to travel through the diameter of the semiconductor wafer without contacting the exposed side, or in other arrangements can contact the exposed side, but due to the energy imparted to the cleaning fluid, the cleaning fluid is still carried away from the distal end of the wafer. In addition, any fluid of liquid that the cleaning fluid encounters is impacted and driven away from the exposed side of the semiconductor wafer. Preventing the buildup of cooling / lubricating liquid on the exposed side of the wafer during the longer cutting times can reduce corrosion, among other things. The cleaning fluid layer is provided by the nozzles through the width of the semiconductor wafer, providing full coverage - although full coverage can be defined as 90% or more of the surface of the semiconductor wafer. In some arrangements, the spurt nozzles that deliver the cleaning fluid are coupled to the movable table through a mounting block and maintain a relative position to the semiconductor wafer as the table moves.

[0055] According to one aspect, a method of manufacturing integrated circuits includes sawing a semiconductor wafer, attaching a plurality of dies to a plurality of lead frames, interconnecting each of the plurality of dies to a corresponding lead frame of the plurality of lead frames, and applying a molding compound over at least a portion of any dies on the lead frames and over at least a portion of the lead frames to each of the lead frames. Sawing the semiconductor wafer includes providing a cutting table, securing the semiconductor wafer in a sawing position, and applying a rotating sawing blade to the wafer secured in the sawing position to cut the wafer into a plurality of separate dies. The sawing of the semiconductor wafer also includes applying a first fluid for cooling to the semiconductor wafer at a location proximate to where the rotating sawing blade contacts the semiconductor wafer, and applying a second fluid or cleaning fluid to substantially all of an exposed side of the semiconductor wafer (top for the orientation of the figures herein). Applying the second fluid includes using a fluid spurt element proximate to and coupled to the cutting table (see, e.g. Figure 2 216 in FIG. 2, Figure 3 322 in FIG. 3, Figure 4 417 in FIG. 4, Figure 5 520 in FIG. 5,Figure 7 702 in). When the semiconductor wafer is mounted in a sawing position, the fluid ejector element is positioned near an edge of the semiconductor wafer to eject the second fluid through substantially all of and substantially parallel to the exposed side of the semiconductor wafer.

[0056] According to one aspect, a method of manufacturing integrated circuits includes sawing a semiconductor wafer along one or more streets formed on the semiconductor wafer into separate die, attaching a plurality of die to a plurality of leadframes, interconnecting each of the plurality of die to a corresponding leadframe of the plurality of leadframes, and applying a molding compound to at least a portion of any die on the leadframe and to at least a portion of each leadframe. The aspect of sawing the semiconductor wafer into separate die includes sawing the semiconductor wafer along the one or more streets to form the plurality of die. The semiconductor wafer has a first side and a second side, with the first side being exposed or open at a top (for the orientation shown in the figure). The aspect of sawing the semiconductor wafer into separate die also includes applying a first fluid for cooling near the location where the semiconductor wafer is sawed, and spraying (at least during sawing) a second fluid or cleaning fluid in a fluid layer across substantially all of the first side of the semiconductor wafer to remove any first fluid that would otherwise reside on the first side of the semiconductor wafer.

[0057] According to one aspect, a method for dicing a semiconductor wafer into separate dies includes mounting the semiconductor wafer on a movable cutting table, cutting the semiconductor wafer, and, at least during cutting, spraying a cleaning fluid through an exposed side (top for the orientation in the figure) of the semiconductor wafer, wherein the cleaning fluid completely covers the semiconductor wafer. Complete coverage means that at least 90% of the exposed side has the cleaning fluid moved through the exposed side. Spraying the cleaning fluid is a fluid that removes any other liquid residing on the exposed side of the semiconductor wafer. Spraying the cleaning fluid includes substantially forming a layer of cleaning fluid that passes over the semiconductor wafer in a plane substantially parallel to the exposed side of the semiconductor wafer to remove any fluid, such as cooling fluid, on the exposed side of the semiconductor wafer.

[0058] According to one aspect, a system for sawing semiconductor wafers includes a movable cutting table for receiving the semiconductor wafer and having a sawing configuration, a dicing saw associated with the cutting table for sawing the semiconductor wafer, and a fluid ejector element coupled to the movable table. The fluid ejector element includes a plurality of nozzles (see, e.g., Figure 2 216 of Figure 3 322 of Figure 4 417 in Figure 5 520 in Figure 7 702 in, the plurality of nozzles are configured to generate a fluid layer that passes through the semiconductor wafer and provides complete coverage.

[0059] In the described embodiments, modifications are possible and other embodiments are possible within the scope of the claims.

Claims

1. A method for manufacturing an integrated circuit, the method comprising: Sawing a semiconductor wafer, comprising: Provide cutting table, fixing the semiconductor wafer in a sawing position, applying a rotating saw blade to the wafer held in the sawing position to cut the wafer into separate dies, applying a first fluid for cooling to the semiconductor wafer near a position where the rotating saw blade contacts the semiconductor wafer, applying a second fluid to substantially all of the exposed side of the semiconductor wafer; and wherein applying the second fluid comprises using a fluid ejector element proximate to and coupled to the cutting table, and wherein when the semiconductor wafer is mounted in the sawing position, the fluid ejector element is positioned proximate an edge of the semiconductor wafer to eject the second fluid across substantially all of and substantially parallel to the exposed side of the semiconductor wafer; attaching the plurality of dies to a plurality of lead frames; interconnecting each die of the plurality of dies to a corresponding lead frame of the plurality of lead frames; and A molding compound is applied to each lead frame over at least a portion of any die on the lead frame and over at least a portion of the lead frame.

2. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes using the fluid ejector element comprising a plurality of nozzles.

3. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes using the fluid ejector element, which includes a plurality of nozzles mounted on the arcuate housing.

4. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes using the fluid ejector element coupled to the cutting table near an edge of a mounting portion of the cutting table, and wherein the fluid ejector element moves with the cutting table.

5. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes mounting a fluid ejector element near an edge of the mounting portion of the cutting table and ejecting the second fluid from one edge to an opposite edge of the semiconductor wafer onto substantially all of the exposed side of the semiconductor wafer through the fluid ejector element.

6. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes using the fluid ejector element, the fluid ejector element including a plurality of nozzles mounted on a curved housing, the plurality of nozzles having a nozzle spacing greater than 2 mm.

7. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying a second fluid includes ejecting the second fluid from the fluid ejector greater than 35 mm from an edge of the cutting table.

8. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes ejecting the second fluid through the fluid ejector element at a rate in the range of 4 to 8 liters per minute.

9. The method for manufacturing an integrated circuit according to claim 1, wherein: Applying the second fluid includes spraying deionized water.

10. The method for manufacturing an integrated circuit according to claim 1, wherein: Holding the semiconductor wafer in a sawing position includes holding the semiconductor wafer comprising copper.

11. The method for manufacturing an integrated circuit according to claim 1, wherein: Holding the semiconductor wafer in a sawing position includes holding a semiconductor wafer comprising a plurality of integrated circuits having a bonding layer on active circuitry, the semiconductor wafer further comprising copper.

12. A method of manufacturing an integrated circuit, the method comprising: sawing the semiconductor wafer into separate dies along one or more streets formed thereon; The method of sawing a semiconductor wafer into separate dies comprises: cutting the semiconductor wafer along the one or more streets to form a plurality of dies, wherein the semiconductor wafer has a first side and a second side, and wherein the first side is exposed, applying a first fluid for cooling near where the semiconductor wafer is cut, and ejecting a second fluid as a fluid layer across substantially all of the first side of the semiconductor wafer at least during sawing to remove any of the first fluid that would otherwise reside on the first side of the semiconductor wafer, wherein ejecting the second fluid comprises using a fluid ejector element coupled to a cutting table and ejecting the second fluid substantially parallel to the first side; attaching the plurality of dies to a plurality of lead frames; interconnecting each die of the plurality of dies to a corresponding lead frame of the plurality of lead frames; and A molding compound is applied to each lead frame over at least a portion of any die on the lead frame and over at least a portion of the lead frame.

13. The method of claim 12, further comprising mounting the semiconductor wafer on a movable cutting table, and wherein the second side rests against the cutting table.

14. The method according to claim 12, wherein: Applying the first fluid includes using a nozzle coupled to the saw blade unit to spray the cooling fluid.

15. The method according to claim 12, wherein: Applying the first fluid includes using a nozzle coupled to the saw blade unit, and wherein ejecting the second fluid includes using a fluid ejector element coupled to the cutting table.

16. The method according to claim 12, wherein: Ejecting a second fluid includes using a fluid ejector element coupled to the cutting table, and wherein the fluid ejector element includes a plurality of nozzles.

17. The method according to claim 12, wherein: Injecting a second fluid includes using a fluid ejector element coupled to the cutting table, and wherein the fluid ejector element includes a plurality of nozzles mounted on a curved housing.

18. The method according to claim 12, wherein: Ejecting a second fluid includes using a fluid ejector element coupled to the cutting table, and wherein the fluid ejector element is coupled to the cutting table near an edge of the cutting table and the fluid ejector element moves with the cutting table.

19. The method according to claim 12, wherein: During sawing, spraying the second fluid includes using a plurality of nozzles mounted on the curved housing and having a nozzle spacing greater than 2 mm to spray the second fluid.

20. The method according to claim 12, wherein Sawing the semiconductor wafer includes sawing the semiconductor wafer including copper.

21. The method according to claim 12, wherein Sawing the semiconductor wafer includes sawing a semiconductor wafer comprising a plurality of integrated circuits having bonding layers on active circuits, the semiconductor wafer further comprising copper.

22. A method for dicing a semiconductor wafer into separate dies, the method comprising: Mounting the semiconductor wafer on a movable cutting table; cutting the semiconductor wafer; spraying a cleaning fluid across the exposed side of the semiconductor wafer at least during dicing, wherein the cleaning fluid completely covers the semiconductor wafer, wherein complete coverage means at least 90% of the exposed side has the cleaning fluid moved across the exposed side, and wherein spraying the cleaning fluid is a fluid that removes any other liquid residing on the exposed side of the semiconductor wafer; Wherein spraying the cleaning fluid includes substantially forming a cleaning fluid layer across the semiconductor wafer substantially parallel to a plane of the exposed side of the semiconductor wafer to remove any fluid on the exposed side of the semiconductor wafer.

23. A system for sawing semiconductor wafers, the system comprising: a movable cutting table for receiving the semiconductor wafer; a dicing saw associated with the movable cutting table for dicing semiconductor wafers; a fluid ejector element coupled to the movable cutting table, the fluid ejector element having a plurality of nozzles configured to substantially generate a fluid layer that passes through the semiconductor wafer parallel to the exposed side of the semiconductor wafer and provides complete coverage, wherein complete coverage means that at least 90% of the exposed side has cleaning fluid moved therethrough.

24. The system of claim 23, wherein: The plurality of nozzles of the fluid ejector element are mounted on a curved housing coupled more than 30 mm from an edge of the cutting table, and wherein a spacing between nozzles of the plurality of nozzles is greater than 2 mm.

25. The system of claim 24, wherein: The arcuate housing has a length including the plurality of nozzles, the length being at least equal to a diameter of a semiconductor wafer to be cut by the system.

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