JP2006324703A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent warpage of a semiconductor wafer when thinning the same. <P>SOLUTION: A semiconductor element is formed on a semiconductor wafer (S1), a masking tape is attached on the surface of the semiconductor wafer (S2), and the rear surface of the semiconductor wafer is ground until the predetermined thickness of the semiconductor wafer is obtained (S3). A die bond film is applied on the rear surface of the semiconductor wafer (S5), and a dicing tape is attached on the rear surface of the semiconductor wafer (S6). The dicing tape attached on the semiconductor wafer is held by a holding jig. The masking tape is peeled off from the surface of the semiconductor wafer (S7), adhesiveness between the semiconductor wafer and die bond film is enhanced by heating the die bond film (S8), and the semiconductor wafer is subjected to dicing (S9) to be separated into each semiconductor chip. The semiconductor chip is die-bonded on a wiring board (S11), and a semiconductor device is produced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device manufacturing technique, and more particularly to a technique effective when applied to a semiconductor device manufacturing method performed by attaching an adhesive sheet to a wafer.

  Japanese Patent Application Laid-Open No. 10-112494 describes a technique for adhering an adhesive sheet for die bonding to a semiconductor wafer. After peeling the release film from the adhesive sheet, the adhesive sheet is attached to the semiconductor wafer. The adhesive sheet at the outer peripheral portion of the wafer is cut (see Patent Document 1).

  In Japanese Patent Laid-Open No. 2002-26039, a backgrinding protective tape is applied to the front surface of a wafer to perform a backgrinding process, and then the backgrinding protective tape is applied to the backside of the wafer. Adhesive adhesive, then peel off the protective tape for back grinding, probe, attach the protective tape for dicing to the adhesive tape for dice bonding, dice, and then use the adhesive tape for dice bonding. A technique for die bonding is described (see Patent Document 2).

  In JP-A-8-181197, a protective tape is applied to the front surface of the wafer, the back surface of the wafer to which the protective tape is applied is ground, and then the back surface of the wafer to which the protective tape is applied is applied. A technique for attaching a dicing tape, attaching a holding jig for holding the dicing tape around the wafer in the dicing tape to which the wafer is attached, and dicing is described (see Patent Document 3).

In Japanese Patent Laid-Open No. 7-22358, the back surface of the wafer is ground with the protective / reinforcing tape affixed to the front surface of the wafer, and the back surface of the wafer is attached with the protective / reinforcing tape affixed to the front surface of the wafer. A technique is described in which a dicing tape is attached to a dicing tape, and then the protective / reinforcing tape is peeled off and then diced (see Patent Document 4).
JP-A-10-112494 JP 2002-26039 A JP-A-8-181197 JP-A-7-22358

  If the thickness of the semiconductor wafer is reduced in order to manufacture a thin semiconductor device, the semiconductor wafer is likely to warp, and the semiconductor wafer is likely to be broken or chipped during each manufacturing process or during transportation between the processes. This reduces the manufacturing yield of the semiconductor device and increases the manufacturing cost of the semiconductor device.

  In the method of attaching the adhesive sheet after peeling off the release film, wrinkles occur on the adhesive sheet attached to the semiconductor wafer due to the balance of the tension of the adhesive sheet when the adhesive sheet is attached to the semiconductor wafer. There are problems such as easy. In addition, when wrinkles occur in the adhesive sheet, it is difficult to reattach the adhesive sheet, so that the semiconductor wafer must be removed as a defective product, which causes problems such as significantly increasing the manufacturing cost of the semiconductor device. is there.

  After peeling off the protective tape for back grinding from the wafer, the method of applying the protective tape for dicing on the adhesive tape for dice bonding is used for dice bonding to the wafer before applying the protective tape for dicing or during the application process. Only the tape-like adhesive is present, and the wafer may be warped. If the semiconductor wafer is warped, the semiconductor wafer is likely to be cracked or chipped during the manufacturing process of the semiconductor device or during transfer between the processes, and the semiconductor wafer is likely to be cracked. This reduces the manufacturing yield of the semiconductor device and increases the manufacturing cost of the semiconductor device.

  In the method of attaching a dicing tape without forming an adhesive layer for die bonding on a wafer, it is necessary to perform die bonding of a semiconductor chip using a silver paste or the like, which complicates the manufacturing process and manufactures a semiconductor device. There are problems such as an increase in cost.

  An object of the present invention is to provide a semiconductor device manufacturing method capable of preventing wafer warpage.

  Another object of the present invention is to provide a semiconductor device manufacturing method capable of reducing the manufacturing cost of the semiconductor device.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  In the method for manufacturing a semiconductor device of the present invention, a protective tape is attached to a first surface of a wafer, a second surface opposite to the first surface of the wafer is ground, and a die bond film is applied to the second surface of the wafer. Is attached, a dicing tape is attached on the die-bonding film on the second surface of the wafer, the protective tape is peeled off from the first surface of the wafer, and the wafer is diced.

  That is, warping of the wafer or the like is prevented by attaching a dicing tape in a state where a protective sheet for back surface grinding is attached.

  In addition, in the method for manufacturing a semiconductor device of the present invention, a laminate of a die bond film and a separator film is attached to the back surface of the wafer so that the die bond film is inside, the separator film is peeled off, and the die bond film is placed on the outer periphery of the wafer. It cuts along.

  That is, after the die-bonding film is attached to the back surface of the wafer together with the separator film, the separator film is peeled off to prevent wrinkles of the separator film.

  The outline | summary of the other invention shown in this application is as follows.

Item 1: (a) preparing a wafer on which a plurality of semiconductor elements are formed,
(B) applying a protective tape to the first surface of the wafer;
(C) grinding a second surface opposite to the first surface of the wafer;
(D) a step of attaching a die bond film to the second surface of the wafer;
(E) a step of attaching a dicing tape on the die-bonding film on the second surface of the wafer;
(F) peeling the protective tape from the first surface of the wafer;
(G) A step of dicing the wafer.

A method of manufacturing a semiconductor device having
The step (d)
(D1) A step of attaching the laminate of the die bond film and the separator film to the second surface of the wafer so that the die bond film is inside,
(D2) a step of peeling the separator film,
(D3) cutting the die bond film along the outer periphery of the wafer;
A method for manufacturing a semiconductor device, comprising:

Item 2: A method of manufacturing a semiconductor device comprising the following steps;
(A) preparing a wafer on which a plurality of semiconductor elements are formed;
(B) a step of attaching a laminate of a die bond film and a separator film to the back surface of the wafer so that the die bond film is on the inside;
(C) a step of peeling the separator film;
(D) A step of cutting the die bond film along the outer periphery of the wafer.

Item 3: In the method of manufacturing a semiconductor device according to Item 2,
A method of manufacturing a semiconductor device, wherein the die bond film includes a thermoplastic resin material.

Item 4: In the method for manufacturing a semiconductor device according to Item 2,
The method of manufacturing a semiconductor device, wherein the separator film is harder than the die bond film.

Item 5: In the method of manufacturing a semiconductor device according to Item 2,
The said die-bonding film functions as an adhesive bond layer at the time of die-bonding the chip | tip obtained by dicing the said wafer, The manufacturing method of the semiconductor device characterized by the above-mentioned.

Item 6: A method of manufacturing a semiconductor device comprising the following steps;
(A) preparing a wafer on which a plurality of semiconductor elements are formed;
(B) applying a protective tape to the first surface of the wafer;
(C) grinding a second surface opposite to the first surface of the wafer;
(D) a step of attaching a laminate of a die bond film and a separator film to the second surface of the wafer so that the die bond film is on the inside;
(E) a step of peeling the separator film;
(F) cutting the die bond film along the outer periphery of the wafer;
(G) a step of attaching a dicing tape on the die-bonding film on the second surface of the wafer;
(H) a step of peeling the protective tape from the first surface of the wafer;
(I) A step of dicing the wafer.

Item 7: In the method of manufacturing a semiconductor device according to Item 6,
A method of manufacturing a semiconductor device, wherein the die bond film includes a thermoplastic resin material.

Item 8: In the method of manufacturing a semiconductor device according to Item 6,
The said die-bonding film functions as an adhesive bond layer at the time of die-bonding the chip | tip obtained by dicing the said wafer at the said (i) process, The manufacturing method of the semiconductor device characterized by the above-mentioned.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  A protective tape is applied to the first surface of the wafer, a second surface opposite to the first surface of the wafer is ground, a die bond film is applied to the second surface of the wafer, and the second surface of the wafer Since the dicing tape is pasted on the die bond film, the protective tape is peeled off from the first surface of the wafer and the wafer is diced, it is possible to prevent the wafer from being warped.

  The laminate of the die bond film and the separator film is attached to the back surface of the wafer so that the die bond film is on the inside, the separator film is peeled off, and the die bond film is cut along the outer periphery of the wafer. It is possible to prevent wrinkles from forming on the die bond film.

  Before describing the present invention in detail, the meaning of terms in the present application will be described as follows.

  1. When a substance name such as PET (polyethylene terephthalate) is mentioned, it does not indicate only the indicated substance, unless specifically stated to that effect, the indicated substance (element, atom group, molecule, polymer, copolymer) , Compounds, etc.) as main components and compositional components.

  In other words, a silicon region is a pure silicon region, a region containing impurity-doped silicon as a main component, or a mixture containing silicon as a main component, such as GeSi, unless otherwise specified. Crystal region and the like. Further, “M” in the case of MOS is not limited to pure metal unless explicitly stated otherwise, but is not limited to a pure metal, but includes a polysilicon (including amorphous) electrode, a silicide layer, and other metal-like properties. It shall include the member which shows. Further, “O” in the case of MOS is not limited to an oxide film such as a silicon oxide film unless otherwise specified, and is not limited to a nitride film, an oxynitride film, an alumina film, or other ordinary dielectrics, high dielectrics. Body, ferroelectric film and the like.

  2. A wafer is a silicon or other semiconductor single crystal substrate (generally a substantially disk shape, a semiconductor wafer, or other semiconductor chips or pellets obtained by dividing them into unit integrated circuit regions and a base region thereof), a sapphire substrate. , Glass substrates, other insulating, anti-insulating or semiconductor substrates, etc. and their composite substrates.

  In the following embodiments, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.

  Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

  Also, components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof is omitted.

  In the drawings used in the present embodiment, hatching may be added even in a plan view for easy understanding of the drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a process flow diagram showing a manufacturing process of the semiconductor device (semiconductor integrated circuit device) of the present embodiment. 2 and 3 are cross-sectional views during the manufacturing process of the semiconductor device of the present embodiment.

  First, as shown in FIG. 2, a wafer (semiconductor substrate for manufacturing a semiconductor integrated circuit) or a semiconductor wafer 1 made of, for example, single crystal silicon is prepared. Then, a plurality of semiconductor elements such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are formed on the semiconductor wafer (wafer) 1 using a known semiconductor device manufacturing technique (step S1). The semiconductor elements formed on the semiconductor wafer 1 are not limited to MOSFETs, and various semiconductor elements can be formed.

  Next, as shown in FIG. 3, a protective tape for back surface grinding is applied to the surface of the semiconductor wafer 1 (the main surface on the semiconductor element forming side of the semiconductor wafer 1 or the semiconductor integrated circuit pattern forming surface: first surface) 1a. (BG sheet, protective sheet) 2 is pasted (step S2). The protective tape 2 protects the front surface 1a of the semiconductor wafer 1 and semiconductor elements formed thereon in a back grinding (BG: back grinding) process of the semiconductor wafer 1 to be described later, and the semiconductor wafer 1 thinned by back grinding. It functions to prevent warping. The protective tape 2 should just have the intensity | strength which can prevent the curvature of a semiconductor wafer at normal temperature. One surface of the protective tape 2 has adhesiveness (adhesiveness), and the protective tape 2 is attached so that the adhesive surface (adhesive surface, adhesive surface) is in contact with the surface 1 a of the semiconductor wafer 1. It is done. The protective tape 2 can be formed of various materials, for example, a laminate of PET (polyethylene terephthalate) and EVA (ethylene vinyl acetate copolymer), vinyl chloride, or the like.

  4-6 is explanatory drawing of the process of affixing the protective tape 2 on the semiconductor wafer 1. FIG.

  As shown in FIG. 4, the protective tape 2 is wound around the protective tape feeding roll 4 in a state where the separator or the separator film 3 is attached (laminated) to the adhesive surface. From the protective tape feed roll 4, the separator film 3 is sent to the separator take-up roll 5 and taken up, and the protective tape 2 from which the separator film 3 has been peeled off passes through the rollers 6, 7 and 8. It is sent to the take-up roll 9 and taken up. The rollers 7 and 8 are configured to be movable in the lateral direction of FIG. 4 (a direction parallel to the main surface of the semiconductor wafer 1), and are placed on the mounting table 10 (so that the surface 1a side of the semiconductor wafer 1 is up). ) The protective tape 2 is moved laterally while pressing the protective tape 2 on the semiconductor wafer 1, and the protective tape 2 is attached to the surface 1 a of the semiconductor wafer 1. Then, the sheet cutter 11 is lowered onto the semiconductor wafer 1, and the protective tape 2 is cut along the outer periphery (shape) of the semiconductor wafer 1 by the blade 11a of the sheet cutter 11, as shown in FIG. At this time, when the sheet cutter 11 rotates, the blade 11 a of the sheet cutter 11 moves along the outer periphery of the semiconductor wafer 1 and cuts the protective tape 2 along the outer periphery of the semiconductor wafer 1. After the protective tape 2 is cut, the sheet cutter 11 is raised, and as shown in FIG. 6, the rollers 7 and 8 move in the horizontal direction and the protective tape 2 (semiconductor wafer 1) other than the part adhered to the semiconductor wafer 1. The protective tape 2) in a state in which the portion adhered to is removed is separated from the semiconductor wafer 1 and taken up by the protective tape take-up roll 9. As a result, the protective tape 2 remains on the surface 1a of the semiconductor wafer 1 in a state of being adhered (adhered).

  After affixing the protective tape 2 on the surface (first surface) 1a of the semiconductor wafer 1 as described above, the surface opposite to the surface 1a of the semiconductor wafer 1, that is, the back surface (second surface) of the semiconductor wafer 1. The surface 1b is ground (step S3). Thereby, the thickness of the semiconductor wafer 1 is reduced. FIG. 7 is an explanatory diagram of the back surface grinding process of the semiconductor wafer 1.

  As shown in FIG. 7, the front surface 1a side of the semiconductor wafer 1 to which the protective tape 2 is attached is held by a BG chuck table 21, and the back surface (second surface) 1b of the semiconductor wafer 1 is ground (polished). For example, the semiconductor wafer 1 held by the BG chuck table 21 is rotated, and the rotating grindstone 23 is pressed against the semiconductor wafer 1 while supplying the grinding water 22 made of pure or the like to scrape the back surface 1b of the semiconductor wafer 1. (Polishing) or the like.

  Next, if necessary, the back surface 1b of the semiconductor wafer 1 is etched with an etchant or the like (step S4). Thereby, the back surface 1b of the semiconductor wafer 1 is cleaned and further flattened. FIG. 8 is an explanatory diagram of the etching process of the back surface of the semiconductor wafer 1.

  As shown in FIG. 8, the front surface 1a side of the semiconductor wafer 1 to which the protective tape 2 is attached is held by the etcher chuck table 24, and the back surface 1b of the semiconductor wafer 1 is etched. For example, the semiconductor wafer 1 held by the etcher chuck table 24 is rotated, and an etching solution 25 made of a mixed solution of hydrofluoric acid and nitric acid is supplied from the nozzle 26 onto the back surface 1b of the semiconductor wafer 1. This is carried out by etching the back surface 1b of 1. The etching solution 25 supplied from the nozzle 26 onto the back surface 1 b of the semiconductor wafer 1 is recovered from the etching solution recovery window 27. The etching process of the back surface 1b of the semiconductor wafer 1 can be omitted.

  Next, the die bond film 30 is affixed to the back surface 1b of the semiconductor wafer 1 (step S5). FIG. 9 is a cross-sectional view showing a state where the die bond film 30 is attached to the semiconductor wafer 1. The die-bonding film 30 functions as an adhesive layer (adhesive layer) for die-bonding each semiconductor chip after the semiconductor wafer 1 is diced and separated into each semiconductor chip (chip) as described later.

  The process of attaching the die bond film 30 to the back surface 1b of the semiconductor wafer 1 will be described in more detail with reference to FIGS.

  As shown in FIG. 10, when the die bond film 30 is attached, a sheet (laminate) 32 in a state where a separator or a separator film 31 is attached to the die bond film 30 is used. The separator film 31 is made of, for example, polyester or PET. The separator film 31 has a relatively hard (hard) leverage, and the thickness can be made relatively thick, for example, about 100 μm. The main component of the die bond film 30 is made of a thermoplastic resin material, such as polyimide. The die bond film 30 is relatively thin and soft, and its thickness can be set to about 25 μm, for example.

  A sheet (laminated sheet) 32 composed of a die bond film 30 and a separator film 31 is wound around a die bond film feeding roll 33. The sheet 32 wound around the die bond film supply roll 33 is fed from the die bond film supply roll 33 through rollers 34 and 35, and is peeled off by the roller 35 into the die bond film 30 and the separator film 31, and the die bond film 30 is die bonded film. The separator film 31 is wound around the separator winding roll 37. The roller 37 is configured to be movable in the lateral direction of FIG. 10 (a direction parallel to the main surface of the semiconductor wafer 1), and is disposed on the mounting table 38 (so that the back surface 1b side of the semiconductor wafer 1 is on the upper side). The sheet 32 is moved in the lateral direction while pressing the sheet 32 on the back surface 1 b of the semiconductor wafer 1, and the sheet 32 is pasted on the back surface 1 b of the semiconductor wafer 1. At this time, the die bond film 30 side of the sheet 32 is in contact with the back surface 1 b of the semiconductor wafer 1. That is, the sheet 32 composed of the die bond film 30 and the separator film 31 is attached to the back surface 1b of the semiconductor wafer 1 so that the die bond film 30 is on the inner side.

  Next, as shown in FIG. 11, the roller 35 moves (in the direction opposite to that when the sheet 32 is attached), the separator film 31 is taken up by the separator take-up roll 37, and the separator film 31 is die-bonded. The film 30 is peeled off. As a result, only the die bond film 30 remains on the back surface 1 b of the semiconductor wafer 1. Then, the sheet cutter 39 is lowered onto the semiconductor wafer 1, and the die bond film 30 is cut along the outer periphery (shape) of the semiconductor wafer 1 by the blade 39 a of the sheet cutter 39. At this time, when the sheet cutter 39 rotates, the blade 39 a of the sheet cutter 39 moves along the outer periphery of the semiconductor wafer 1 and cuts the die bond film 30 along the outer periphery of the semiconductor wafer 1.

  After the die bond film 30 is cut, the sheet cutter 39 is raised, and the die bond film 30 (on the semiconductor wafer 1) other than the portion bonded to the semiconductor wafer 1 is wound by winding the die bond film winding roll 36 as shown in FIG. The die bond film 30) in a state where the bonded portion is hollowed is separated from the semiconductor wafer 1 and taken up by the die bond film take-up roll 36. As a result, the die bond film 30 remains on the back surface 1b of the semiconductor wafer 1 in a state of being adhered (adhered). Then, using a heating device (not shown) (for example, a heater built in the mounting table 38) or the like, the semiconductor wafer 1 is heated to temporarily bond the semiconductor wafer 1 and the die bond film 30 together. The heating temperature (first temperature) at this time is a relatively low temperature, for example, about 100 ° C. Since the heating temperature for temporary bonding between the semiconductor wafer 1 and the die bond film 30 is relatively low, the protective tape 2 attached to the surface 1a of the semiconductor wafer 1 does not warp. Therefore, the semiconductor wafer 1 can be prevented from warping. Here, the temporary bonding means that the semiconductor wafer 1 and the die bond film 30 have an adhesive force that does not peel off during the subsequent process (up to a heating process at a second temperature described later) or during the transfer between processes. If you do. If the adhesiveness between the die bond film 30 and the semiconductor wafer 1 is secured to some extent without heating, the heating step for temporary bonding can be omitted.

  In the present embodiment, as described above, the die bond film 30 is attached to the back surface 1b of the semiconductor wafer 1 together with the separator film 31, and then only the separator film 31 is peeled off to cut the die bond film 30 into a predetermined shape. If the die bond film 30 is attached to the back surface 1b of the semiconductor wafer 1 alone, the die bond film 30 is relatively thin and soft, so that the attached die bond film 30 is wrinkled, and the die bond film 30 and the semiconductor wafer are bonded. Air bubbles easily enter between 1 and 1. When the die bond film 30 stuck on the semiconductor wafer 1 is wrinkled or air bubbles enter, it is not easy to peel off the die bond film 30 (removing the die bond film 30 and reattaching another die bond film). The entire semiconductor wafer 1 becomes defective and cannot be used for manufacturing a semiconductor device. This significantly reduces the manufacturing yield of the semiconductor device and increases the manufacturing cost of the semiconductor device. In the present embodiment, since the die bond film 30 is attached together with the separator film 31 that is relatively hard and sticky when the die bond film 30 is attached to the semiconductor wafer 1, the die bond film attached to the back surface 1b of the semiconductor wafer 1 is attached. It is possible to prevent wrinkles and the like from occurring at 30. It is possible to prevent air bubbles and the like from entering between the semiconductor wafer 1 and the die bond film 30. Moreover, since the separator film 31 is peeled before the die bond film 30 is cut, the thickness of the separator film 31 can be made relatively thick, and the separator film 31 is made relatively hard (hard) to prevent wrinkles of the die bond film 30. It is easy to do. In the present embodiment, since the main component of the die bond film 30 is made of a thermoplastic resin, only the separator film 31 can be peeled off after the sheet 32 is attached to the semiconductor wafer 1.

  Further, when the die bonding film 30 is attached to the back surface 1 b of the semiconductor wafer 1 after the protective tape 2 is peeled off from the semiconductor wafer 1, the thin semiconductor wafer 1 is warped due to the protective tape 2 being peeled off from the semiconductor wafer 1. Therefore, the die bond film 30 is pasted on the warped semiconductor wafer 1, and the die bond film 30 stuck on the back surface 1 b of the semiconductor wafer 1 is likely to be wrinkled. However, in the present embodiment, the die bond film 30 is attached to the back surface 1 b of the semiconductor wafer 1 in a state where the protective tape 2 is attached to the front surface 1 a of the semiconductor wafer 1. For this reason, the die-bonding film 30 can be attached in a state where the warp of the semiconductor wafer 1 is suppressed by the protective tape 2. Therefore, wrinkles and the like can be more reliably prevented from occurring in the die bond film 30 attached to the back surface 1b of the semiconductor wafer 1.

  After the die bond film 30 is attached to the back surface 1b of the semiconductor wafer 1 as described above, the dicing tape (wafer sheet) is attached to the back surface 1b (surface on which the die bond film 30 is attached: second surface) side of the semiconductor wafer 1. ) 40 is attached (wafer mount: step S6). FIG. 13 is a plan (top) view showing a state where the dicing tape 40 is attached to the semiconductor wafer 1, and FIG. 14 is a cross-sectional view taken along the line AA.

  The dicing tape 40 is an extensible tape (sheet) having one surface having adhesiveness, and the back surface 1b of the semiconductor wafer 1 is attached to the adhesive surface (adhesive surface). Therefore, the dicing tape 40 is affixed on the die bond film 30 on the back surface 1 b of the semiconductor wafer 1. The dicing tape 40 is held by a holding jig (carrier jig, carrier ring, frame: holder) 41 arranged around the semiconductor wafer 1. The holding jig 41 is made of, for example, a metal material (for example, SUS) or the like, and is, for example, a ring-shaped holding jig larger than the semiconductor wafer 1. The dicing tape 40 functions to hold each cut piece (semiconductor chip) after a dicing process of the semiconductor wafer 1 described later.

  FIG. 15 is an explanatory diagram of a process of attaching the dicing tape 40 to the semiconductor wafer 1. As shown in FIG. 15, a dicing tape 40 is attached to the back surface 1 b side of the semiconductor wafer 1, and a ring-shaped holding jig 41 larger than the semiconductor wafer 1 is attached to the peripheral (peripheral) dicing tape 40 of the semiconductor wafer 1. In order to improve the adhesion between the semiconductor wafer 1 and the dicing tape 40, the dicing tape 40 attached to the back surface 1b (die bond film 30) of the semiconductor wafer 1 disposed on the mounting table 42 is applied to the application roller. 43 is pressed. After attaching the semiconductor wafer 1 to the dicing tape 40, the holding jig 41 can be attached to the dicing tape 40. After the dicing tape 40 is attached to the holding jig 41, the holding jig 41 is held by the holding jig 41. The back surface 1b side of the semiconductor wafer 1 can also be attached to the dicing tape 40.

  Next, the protective tape 2 is peeled from the surface 1a of the semiconductor wafer 1 (step S7). FIG. 16 is an explanatory diagram of a process of peeling the protective tape 2 from the semiconductor wafer 1.

  As shown in FIG. 16, the peeling tape 52 wound around the peeling tape feeding roll 51 is fed through the rollers 53 and 54 and wound around the peeling tape take-up roll 55. One surface of the release tape 52 has high adhesiveness (adhesiveness stronger than the adhesive surface of the protective tape 2), and the adhesive surface (adhesive surface) is in the horizontal direction of FIG. It is pressed and affixed to the surface 1a of the semiconductor wafer 1, that is, the protective tape 2, by a roller 54 that moves in a direction parallel to the main surface. Then, the roller 54 is moved (in the direction opposite to that when the release tape 52 is attached), and the release tape 52 is wound around the release tape take-up roll 55. At this time, since the surface of the peeling tape 52 that contacts the protective tape 2 has high adhesiveness, the protective tape 2 is peeled from the semiconductor wafer 1 together with the peeling tape 52. Thereby, the protective tape 2 can be peeled from the surface 1a of the semiconductor wafer 1, and the surface (semiconductor element formation surface) 1a of the semiconductor wafer 1 is exposed.

  Next, in order to improve (improve) the adhesion between the semiconductor wafer 1 and the die bond film 30, the semiconductor wafer 1 (die bond film 30) is heated to a second temperature (step S8). FIG. 17 is an explanatory diagram of the heating process of the semiconductor wafer 1.

  As shown in FIG. 17, the semiconductor wafer 1 attached to the dicing tape 40 held by the holding jig 41 is heated by the heater 60. The heating temperature (second temperature) at this time is higher than the heating temperature (first temperature) for temporarily bonding the semiconductor wafer 1 and the die bond film 30 to, for example, about 180 ° C. (heating time is, for example, 2). Seconds). As a result, the die bond film 30 containing the thermoplastic resin material as a main component is softened and then cured (cured) by cooling, so that the semiconductor wafer 1 and the die bond film 30 are in close contact with each other.

  Since this heating process is performed at a relatively high temperature (second temperature: for example, 180 ° C.), the semiconductor wafer 1 is likely to warp. For this reason, if the heating to the second temperature is performed after the die bond film 30 is attached to the semiconductor wafer 1 and before the dicing tape 40 is attached, the semiconductor wafer 1 may be warped. This causes cracking of the semiconductor wafer 1 during the subsequent processes and conveyance. In the present embodiment, the heating step to the second temperature is performed after the dicing tape 40 is attached. For this reason, the heating step to the second temperature is performed in a state where the semiconductor wafer 1 is attached to the dicing tape 40 held by the holding jig 41. Since the dicing tape 40 held by the holding jig 41 holds (reinforces) the semiconductor wafer 1 attached thereto, warping of the semiconductor wafer 1 in the heating process can be accurately prevented.

  Moreover, in this Embodiment, since the protective tape 2 is peeled before this heating process (heating process at 2nd temperature), it is not necessary to use a highly heat-resistant material for the protective tape 2. Even if the protective tape 2 is made of a material that deforms at the second temperature, the protective tape 2 is heated to the second temperature in the absence of the protective tape 2 (after peeling). The semiconductor wafer 1 does not warp. The peeling process of the protective tape 2 can also be performed after this heating process. In this case, it is more preferable to form the protective tape 2 from a material that has high heat resistance and is not easily deformed even at the second temperature. If the protective tape 2 is formed of such a material, the protective tape 2 is prevented from being deformed to warp the semiconductor wafer 1 or to be difficult to peel off when the protective tape 2 is peeled later. can do. The dicing tape 40 is more preferably made of a material that can withstand the second temperature (not easily deformed).

  Next, the semiconductor wafer 1 is diced (step S9). FIG. 18 is an explanatory diagram of the dicing process of the semiconductor wafer 1.

  As shown in FIG. 18, a blade (on a semiconductor wafer 1 disposed on a mounting table 71 and affixed to a dicing tape 40 held by a holding jig 41 is rotated at high speed by a spindle 72 of a dicing apparatus ( Dicing blade 73) is used for dicing or cutting from the surface 1a side. A plurality of semiconductor elements (not shown) are formed on the semiconductor wafer 1 as described above, and dicing is performed along scribe areas (scribe lines) between the semiconductor element formation areas. In FIG. 18, the dicing tape 40 is diced or cut halfway. The semiconductor wafer 1 is separated into a chip area (unit integrated circuit area) or simply a chip (unit integrated circuit area or a base portion thereof) or a semiconductor chip 80 by dicing, and each semiconductor chip (chip) 80 is held by a dicing tape 40. The Further, the depth of dicing can be set to the middle of the die bond film 30 or the middle of the semiconductor wafer 1. Also, a dicing method such as a half cut for dicing to a depth of about half the thickness of the semiconductor wafer 1, a semi-full cut for dicing while leaving the semiconductor wafer 1 slightly, or a full cut for completely cutting the semiconductor wafer 1 can be used. .

  Next, the process which reduces the adhesiveness (adhesiveness) of the dicing tape 40 is performed. For example, the adhesiveness of the dicing tape 40 is reduced by irradiating with ultraviolet rays (UV) (step S10). FIG. 19 is an explanatory diagram of a process for reducing the adhesiveness of the dicing tape 40.

  As shown in FIG. 19, a UV irradiation device or a UV lamp (ultraviolet lamp) 81 is used to apply ultraviolet light to the diced semiconductor wafer 1 attached to the dicing tape 40 held by the holding jig 41. Irradiate (UV). Ultraviolet rays from the UV lamp 81 are directly or reflected by the reflecting plate 82 and irradiated onto the dicing tape 40. In the present embodiment, a material whose adhesiveness is lowered by ultraviolet rays is used for the dicing tape 40 (or an adhesive layer of the dicing tape 40). For example, an ultraviolet curable resin or the like is used. Thereby, the adhesive strength of the dicing tape 40, that is, the adhesive strength between the dicing tape 40 and the die bond film 30 can be reduced by ultraviolet irradiation.

  Next, the semiconductor chip (chip) 80 is die-bonded (step S11). FIG. 20 is an explanatory diagram of the die bonding process of the semiconductor chip 80.

  As described above, the semiconductor wafer 1 is separated into a plurality of semiconductor chips 80 by the dicing process, and the adhesiveness between each semiconductor chip 80 (and the die bond film 30 on the back surface thereof) and the dicing tape 40 is reduced by the ultraviolet irradiation. Yes. As shown in FIG. 20, the semiconductor chip 80 is adsorbed by a collet 90 of a die bonder (die bonding apparatus), and is arranged (mounted) at a predetermined position on the wiring board 91. When the semiconductor chip 80 is attracted and transferred from the diced semiconductor wafer 1 by the collet 91, the needle-shaped pins 92 are pushed up from the back surface side (dicing tape 40 side) of the semiconductor wafer 1 (chip pushing up), The semiconductor chip 80 is separated and adsorbed. Further, when the semiconductor chip 80 is disposed on the wiring substrate 91, the back surface side (side to which the die bond film 30 is bonded: the second surface side) of the semiconductor chip 80 is the wiring substrate 91 side (lower side). Like that. Accordingly, the semiconductor chip 80 is disposed on the wiring substrate 91 via the die bond film 30.

  Although it is possible to mount only one semiconductor chip 80 on the wiring board 91, as shown in FIG. 20, another semiconductor chip (semiconductor device) 80a is first arranged on the wiring board 91, and the semiconductor chip 80a. The semiconductor chip 80 can also be disposed on the top. The semiconductor chip 80a can be manufactured in the same manner as the semiconductor chip 80, and a die bond film 30a similar to the die bond film 30 is attached to the back surface thereof. The number of semiconductor chips stacked (stacked) on the wiring board 91 can be any number.

  Next, the wiring substrate 91 on which the semiconductor chips 80 and 80a are mounted is heated to a predetermined temperature (for example, about 180 ° C.) (that is, the die bond films 30 and 30a are heated) to soften the die bond films 30 and 30a. Thus, the semiconductor chip 80 is bonded to the semiconductor chip 80a through the die bond film 30, and the semiconductor chip 80a is bonded to the wiring substrate 91 through the die bond film 30a. Thereafter, the die-bonding films 30 and 30a are cured by cooling, the semiconductor chip 80 is fixed to the semiconductor chip 80a via the die-bonding film 30, and the semiconductor chip 80a is fixed to the wiring substrate 91 via the die-bonding film 30a. When the semiconductor chip 80 is directly mounted on the wiring substrate 91, the die bond film 30 is heated and softened, and then cooled and cured, so that the semiconductor chip 80 is directly fixed to the wiring substrate 91 through the die bond film 30. Is done.

  When die bonding of a semiconductor chip using a silver paste or the like without using the die bond film 30, an adhesive such as a silver paste containing an organic solvent is applied to the back surface of the semiconductor chip. There is a risk of volatilization and diffusion, and there is a problem in the working environment. In addition, since an adhesive such as a silver paste is applied to the back surface of the semiconductor chip and adhered to a wiring board or the like, the manufacturing process becomes complicated, increasing the manufacturing cost of the semiconductor device. Further, when mounting other semiconductor chips on the semiconductor chip as described above (when stacking a plurality of semiconductor chips), the silver paste for bonding the upper semiconductor chip to the lower semiconductor chip is lower. There is a risk of spreading to the electrode pads of the semiconductor chip on the side, reducing the reliability of the semiconductor device. In the present embodiment, die bonding of the semiconductor chip 80 is performed using the die bond film 30. Since the semiconductor chip 80 is die-bonded (adhered) by the die-bonding film 30, there are no problems in the working environment, the operability is improved, and the manufacturing process is simplified. In addition, a plurality of semiconductor chips can be easily stacked. For this reason, the reliability of the semiconductor device is improved. In addition, the manufacturing yield of the semiconductor device can be improved, and the manufacturing cost of the semiconductor device can be reduced.

  After the die bonding process as described above, as shown in FIG. 21, the electrode pads on the surfaces of the semiconductor chips 80 and 80a and the wiring on the wiring board 91 are electrically connected by bonding wires 92 and 92a, respectively. To do. Then, a sealing resin (mold resin) 93 is formed on the wiring board 91 so as to cover the semiconductor chips 80 and 80a and the bonding wires 92 and 92a, and solder balls 94 and the like are provided as external connection terminals on the bottom surface of the wiring board 91. The wiring board 91 is cut as necessary. Thereby, the semiconductor device 100 of the present embodiment as shown in FIG. 21 is manufactured.

  The semiconductor device 100 of FIG. 21 is manufactured on the wiring board 91 in the same manner as the semiconductor chip 80, and the semiconductor chip 80a having a different external dimension from the semiconductor chip 80 and the semiconductor chip 80 are stacked on the wiring board 91. This is a two-stage stacked semiconductor device. As the semiconductor chip 80 and the semiconductor chip 80a, a semiconductor chip in which various semiconductor elements are formed can be used as necessary. For example, the lower (lower) semiconductor chip 80a is an 8M SRAM, and the upper layer ( The upper semiconductor chip 80 is a 4M SRAM. In the semiconductor device 100 of FIG. 21, both the upper semiconductor chip 80 and the lower semiconductor chip 80a are electrically connected to the wiring substrate 91 (wiring) by wire bonding 92 and 92a. 80a can also be electrically connected to the wiring substrate 91 (wiring thereof) by flip-chip connection or the like.

  In such a semiconductor device in which a plurality of semiconductor chips are stacked (multi-layer semiconductor device), the thickness of each semiconductor chip is reduced in order to suppress an increase in the thickness of the semiconductor device due to the stacking of the plurality of semiconductor chips. It needs to be relatively thin. For example, in the semiconductor device 100 shown in FIG. 21, the vertical and horizontal dimensions are about 6.5 mm, the thickness dimension is about 1.4 mm, and the thicknesses of the semiconductor chips 80 and 80a are each about 150 μm, for example. It is. When manufacturing such semiconductor chips 80 and 80a having a relatively small thickness, it is necessary to make the semiconductor wafer thin (for example, up to about 150 μm). However, if the semiconductor wafer is thinned by back grinding or the like, the semiconductor wafer is likely to warp, and the semiconductor wafer is likely to crack or chip. This reduces the manufacturing yield of the semiconductor device. In the present embodiment, after the protective tape 2 is attached to the semiconductor wafer 1, the semiconductor wafer 1 is held (fixed, fixed) by the protective tape 2 or the dicing tape 40 (held by the holding jig 41) until the dicing step. The warped state of the semiconductor wafer 1 can be suppressed or prevented. In the present embodiment, the die bond film 30 is attached to the back surface 1b of the semiconductor wafer 1 with the protective tape 2 attached to the front surface 1a of the semiconductor wafer 1, and the semiconductor wafer 1 is attached (by the holding jig 41). Since the heating for improving the adhesion (adhesiveness) between the semiconductor wafer 1 and the die bond film 30 is performed after being attached to the dicing tape 40 and fixed, the warpage of the semiconductor wafer 1 due to the heating is prevented. . Therefore, even if the thickness of the semiconductor wafer 1 is reduced by backside grinding, the semiconductor wafer 1 is hardly warped, and it is possible to prevent cracking or chipping of the semiconductor wafer 1 during each process or during conveyance between processes. it can. For this reason, the manufacturing yield of the semiconductor chip (semiconductor device) manufactured from the semiconductor wafer 1 and the semiconductor device on which the semiconductor chip is mounted can be improved, and the manufacturing cost can be reduced. In addition, the semiconductor device can be reduced in size and thickness.

  FIG. 22 shows a four-stage stacked semiconductor device 100a in which four semiconductor chips 80b to 80e are stacked. The semiconductor chips 80b to 80e stacked (stacked) on the wiring substrate 91 can be manufactured in the same manner as the semiconductor chip 80, and are die-bonded by the same die bond films 30b to 30e as the die bond film 30. ing.

  In the semiconductor device 100a of FIG. 22, the semiconductor chip 80b is mounted on the wiring substrate 91, the spacer 101 is mounted on the semiconductor chip 80b, and the semiconductor chips 80c to 80e are sequentially mounted on the spacer 101. The electrode pads of the semiconductor chips 80b to 80e are electrically connected to the electrode pads of the wiring board 91 through bonding wires 92b to 92e. As the semiconductor chips 80b to 80e, semiconductor chips on which various semiconductor elements are formed can be used as necessary. For example, the semiconductor chip 80b is a 64M flash memory, and the semiconductor chip 80c is a 32M flash memory. The semiconductor chip 80d is an 8M SRAM, and the semiconductor chip 80e is a 32M PSRAM. As the spacer 101, for example, a chip obtained by dicing a semiconductor wafer on which a semiconductor element is not formed into a predetermined shape can be used, and the chip is mounted on the semiconductor chip 80 b by a die bond film 102.

  For example, the spacer 101 is inserted between the semiconductor chip 80b and the semiconductor chip 80c so that the bonding wire 92b connected to the semiconductor chip 80b does not contact the semiconductor chip 80c, and has an outer shape smaller than the semiconductor chips 80b and 80c. Have dimensions. For example, when the outer dimensions of the semiconductor chip 80b and the outer dimensions of the semiconductor chip 80c are close, it is effective to insert the spacer 101 between the semiconductor chip 80b and the semiconductor chip 80c.

  The semiconductor device 100a has vertical and horizontal dimensions of about 10 mm and 11.5 mm, for example, and a thickness direction of about 1.4 mm. Since the semiconductor device 100a in FIG. 22 has a larger number of semiconductor chips (and spacers) than the semiconductor device 100 in FIG. 21, the thickness of the semiconductor chips 80b to 80e and the spacer 101 is relatively thin, for example, about 90 μm. It is. For this reason, when manufacturing the semiconductor device 100a (semiconductor chips 80b to 80e), it is necessary to make the semiconductor wafer thinner (for example, up to about 90 μm) by back surface grinding. However, according to the manufacturing method of the semiconductor device of the present embodiment. For example, even when the semiconductor wafer is made extremely thin, warping or cracking of the semiconductor wafer can be prevented, and the manufacturing yield of a semiconductor chip manufactured from the semiconductor wafer and a semiconductor device using the semiconductor chip can be improved. Therefore, the manufacturing cost of the semiconductor chip and the semiconductor device can be reduced.

  The manufacturing process of the present embodiment is suitable for manufacturing a semiconductor chip (semiconductor device) having a relatively small thickness. For example, the semiconductor wafer is ground to a thickness of about 200 μm or less, and the semiconductor chip has a thickness of about 200 μm or less. It is more preferable to manufacture (semiconductor device). When the thickness of the semiconductor wafer is about 200 μm or less, the semiconductor wafer is likely to warp. However, according to the present embodiment, it is possible to manufacture the semiconductor device while suppressing the warpage of the semiconductor wafer. Also, in the case of manufacturing a semiconductor device formed by stacking a plurality of semiconductor chips (on a wiring board or the like), the thickness of each semiconductor chip is relatively thin, so that the manufacturing of the semiconductor device of the present embodiment If the process is applied, the effect is great.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention is suitable for application to a method for manufacturing a semiconductor device, for example, by attaching an adhesive sheet to a wafer.

It is a process flow figure showing a manufacturing process of a semiconductor device which is one embodiment of the present invention. It is sectional drawing in the manufacturing process of the semiconductor device of one embodiment of this invention. FIG. 3 is a cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 2; It is explanatory drawing of the process of affixing a protective tape on a semiconductor wafer. FIG. 5 is an explanatory diagram of the manufacturing process of the semiconductor device, following FIG. 4; FIG. 6 is an explanatory diagram of the manufacturing process of the semiconductor device, following FIG. 5; It is explanatory drawing of the back surface grinding process of a semiconductor wafer. It is explanatory drawing of the etching process of the back surface of a semiconductor wafer. It is sectional drawing which shows the state which affixed the die-bonding film on the semiconductor wafer. It is explanatory drawing of the process of affixing a die bond film on the back surface of a semiconductor wafer. FIG. 11 is an explanatory diagram of the manufacturing process of the semiconductor device, following FIG. 10; FIG. 12 is an explanatory diagram of the manufacturing process of the semiconductor device, following FIG. 11; It is a top view which shows the state which affixed the dicing tape on the semiconductor wafer. It is sectional drawing of the AA line of FIG. It is explanatory drawing of the process of affixing a dicing tape on a semiconductor wafer. It is explanatory drawing of the process of peeling a protective tape from a semiconductor wafer. It is explanatory drawing of the heating process of a semiconductor wafer. It is explanatory drawing of the dicing process of a semiconductor wafer. It is explanatory drawing of the process of reducing the adhesiveness of a dicing tape. It is explanatory drawing of the die-bonding process of a semiconductor chip. It is sectional drawing of the semiconductor device of one embodiment of this invention. It is sectional drawing of the semiconductor device which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 1a Front surface 1b Back surface 2 Protective tape 3 Separator film 4 Feeding roll 5 Separator take-up roll 6 Roller 7 Roller 8 Roller 9 Protective tape take-up roll 10 Mounting stand 11 Sheet cutter 11a Blade 21 BG chuck table 22 Grinding water 23 Grinding stone 24 Etcher Chuck Table 25 Etching Solution 26 Nozzle 27 Etching Solution Recovery Window 30 Die Bond Films 30b-30f Die Bond Film 31 Separator Film 32 Sheet 33 Die Bond Film Feeding Roll 34 Roller 35 Roller 36 Die Bond Film Winding Roll 37 Separator Winding Roll 38 Mounting table 39 Sheet cutter 39a Blade 40 Dicing tape 41 Holding jig 42 Mounting table 43 Adhering roller 51 Release tape feeding roll 5 Release tape 53 Roller 54 Roller 55 Release tape take-up roll 56 Mounting table 60 Heater 71 Mounting table 72 Spindle 73 Blades 80a to 80e Semiconductor chip 81 UV lamp 82 Reflector 90 Collet 91 Wiring substrates 92a to 92f Bonding wire 93 Sealing resin 94 Solder ball 100 Semiconductor device 100a Semiconductor device 101 Spacer 102 Die bond film

Claims (12)

A method of manufacturing a semiconductor device comprising the following steps:
(A) preparing a wafer on which a plurality of semiconductor elements are formed;
(B) applying a protective tape to the first surface of the wafer;
(C) grinding a second surface opposite to the first surface of the wafer;
(D) a step of attaching a die bond film to the second surface of the wafer;
(E) a step of attaching a dicing tape on the die-bonding film on the second surface of the wafer;
(F) a step of peeling the protective tape from the first surface of the wafer;
(G) A step of dicing the wafer. In the manufacturing method of the semiconductor device according to claim 1,
A method of manufacturing a semiconductor device, wherein the die bond film includes a thermoplastic resin material. In the manufacturing method of the semiconductor device according to claim 1,
The method of manufacturing a semiconductor device, wherein the first surface of the wafer is a surface on which the plurality of semiconductor elements are formed. In the manufacturing method of the semiconductor device according to claim 1,
The said die-bonding film functions as an adhesive bond layer at the time of die-bonding the chip | tip obtained by dicing the said wafer, The manufacturing method of the semiconductor device characterized by the above-mentioned. In the manufacturing method of the semiconductor device according to claim 1,
A method of manufacturing a semiconductor device, comprising the step of heating the die bond film after the step (e) and before the step (f). In the manufacturing method of the semiconductor device according to claim 1,
A method of manufacturing a semiconductor device, comprising the step of heating the die bond film after the step (f) and before the step (g). In the manufacturing method of the semiconductor device according to claim 1,
A step of heating the die bond film after the step (e) and before the step (f) in order to improve the adhesion between the die bond film and the wafer. Method. In the manufacturing method of the semiconductor device according to claim 1,
After the step (f) and before the step (g), the method includes the step of heating the die bond film in order to improve the adhesion between the die bond film and the wafer. Method. In the manufacturing method of the semiconductor device according to claim 1,
After the step (d) and before the step (e), the step of heating the die bond film to a first temperature,
A method of manufacturing a semiconductor device, comprising the step of heating the die bond film to a second temperature higher than the first temperature after the step (e) and before the step (f). In the manufacturing method of the semiconductor device according to claim 1,
After the step (d) and before the step (e), the step of heating the die bond film to a first temperature,
A method of manufacturing a semiconductor device, comprising the step of heating the die bond film to a second temperature higher than the first temperature after the step (f) and before the step (g). In the manufacturing method of the semiconductor device according to claim 1,
In the step (e), the dicing tape is held by a holder disposed around the wafer,
In the step (g), the wafer attached to the dicing tape held by the holder is diced. In the manufacturing method of the semiconductor device according to claim 1,
In the step (c), the wafer is ground so as to have a thickness of 200 μm or less.

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