JP2006294685A - Semiconductor chip having back metal film and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor chip that can prevent a chip yield from decreasing due to the damage of a wafer in handling, can prevent the chipping of a chip cutting surface and the separation of a back metal film, and has the back metal film. <P>SOLUTION: In the manufacturing method of the semiconductor chip having the back metal film, a rear 1b' of the wafer where a basic component, such as a transistor and an electronic circuit, for each chip is manufactured on a surface 1a is joined to a first support for fixing the wafer, the chip 9 is divided into pieces from the wafer in this state, the surface 1a of the chip 9 divided into pieces is connected to a second support 11 for moving the chip 9 from the first support to the second supports 11, 13, a metal film 15 is formed on the exposed surfaces of the second supports 11, 13, and the chip 9 is separated from the second support 11, thus obtaining the chip 9 that has the back metal film and is divided into pieces. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor chip having a back metal film, and a semiconductor chip having a back metal film obtained by using this method.

  Some semiconductor chips have a solid metal film formed on the back surface of the chip (the surface on which a connection terminal for connecting the chip to an external circuit is not formed). For example, in a compound semiconductor chip, a solid metal film is often formed as a ground electrode on the back surface of the chip. Also, in a silicon chip, a solid metal film may be formed on the back surface of the chip in order to improve the heat dissipation of the die (chip) after die attachment to a substrate or the like.

  A chip having such a back surface metal film generally forms a solid metal film on the entire back surface of the wafer (the surface on which the chip connection terminals are not formed) at the wafer stage before each chip is singulated. These are manufactured by dicing them together with a solid metal film.

  With reference to FIG. 4A to FIG. 4D, a conventional method for manufacturing a semiconductor chip having a back metal film, which is generally performed, will be described. As shown in FIG. 4A, a wafer (device wafer) 101 on which transistors and electronic circuits (not shown) as basic components for each chip have been manufactured is received. Transistors, electronic circuits, and the like (not shown) are formed on the surface 101a of the wafer 101, and connection terminals 103 are formed on the surface 101a. In order to make the wafer 101 have a predetermined thickness (for example, 200 μm), the back surface 101b of the wafer 101 is ground to obtain a wafer 101 ′ having a new back surface 101b ′ as shown in FIG. Next, as shown in FIG. 4C, a solid metal film 105 such as gold (Au), copper (Cu), or aluminum (Al) is formed on the entire back surface of the wafer 101 'by sputtering or vapor deposition. Subsequently, as shown in FIG. 4D, each chip 111 is cut from the wafer by sticking the metal film 105 to the dicing tape 107 to fix the wafer and dicing with the dicing blade 109. The At this time, dicing is stopped when the tape 107 is cut halfway. Thereafter, by picking up from the dicing tape 107 (not shown), the chip 111 separated into individual pieces is obtained. Such a general method for obtaining individual chips by dicing from a wafer is described in paragraphs 0067 to 0068 of Patent Document 1, for example.

  In the above-described general method for obtaining a chip provided with a metal film on the back surface by dicing the wafer on which the metal film is formed, when the wafer thickness is reduced to 200 μm or less, the wafer is handled at the time of handling (particularly by grinding). During the formation of the metal film after the predetermined thickness is reached, the wafer is likely to be damaged, resulting in a decrease in yield. In addition, since the metal film is diced together with the wafer, the dicing blade (a cutting blade obtained by solidifying diamond abrasive grains with resin) is likely to be clogged, resulting in a reduction in processing quality and an increase in chipping on the chip cut surface. Further, the metal film is easily peeled off.

JP 2004-165277 A

  The present invention is effective for preventing a reduction in chip yield due to wafer breakage during handling, and is capable of preventing chipping of a chip cut surface and peeling of a back surface metal film, and a semiconductor chip having a back surface metal film. The purpose is to provide a new manufacturing method.

  A method for manufacturing a semiconductor chip having a backside metal film according to the present invention includes fixing the wafer by bonding the backside of the wafer on which the basic components (transistors, electronic circuits, etc.) for each chip are formed on the surface to the first support. The chips are separated from the wafer in a state of being bonded to the first support, and the surface of the separated chips is bonded to the second support, so that the chips are transferred from the first support to the second support. Transferring, forming a metal film on the exposed surface of the chip on the second support, and separating the chip from the second support to obtain an individualized chip having a back metal film .

  As the first support, it is possible to use a support capable of fixing and dicing the wafer, for example, an ultraviolet curable dicing tape.

  As the second support, a support made of a rigid material having a surface that can be bonded to the chip can be used. If the rigid material support itself cannot be coupled to the chip, a coupling member made of a material that can be coupled to the chip can be provided on the surface to be coupled to the chip.

  Preferably, the second support is made of a plate-like material made of silicon, glass or metal material, or is a glass epoxy substrate. When any of these is used as the second support, it cannot be bonded to the chip itself, so as a bonding member for the surface to be bonded to the chip, for example, an ultraviolet curable tape or a heat release type tape. Or a sheet-like material can be used.

  The back metal film can be formed on the entire exposed surface of the chip transferred onto the second support, or it can be formed on a part of the exposed surface of the chip transferred onto the second support. .

  A semiconductor chip having a back surface metal film according to the present invention is a semiconductor chip in which basic components are formed on the surface, connection terminals are located, and a metal film is provided on the back surface, and the back surface metal film is a side surface from the back surface of the chip. It is characterized by extending.

  The back metal film may cover the entire back surface and side surface of the chip, or may cover only a part of one or both of the back surface and side surface of the chip.

  According to the method for manufacturing a semiconductor chip having a backside metal film of the present invention, it is possible to prevent the chip yield from being reduced due to breakage of the wafer during handling, and to prevent chipping of the chip cut surface and peeling of the metal film. be able to.

  In the method of manufacturing a semiconductor chip having a backside metal film according to the present invention, chips are separated from the wafer in a state of being bonded to the first support, and transferred from the first support to the second support in a lump. A metal film is formed on the exposed surface of the singulated chip.

  The method of the present invention will be described with reference to the drawings. What is described here is an example of the present invention, and the present invention is not limited thereto.

  As shown in FIG. 1A, a wafer (device wafer) 1 in which basic components (not shown) for each chip such as a transistor and an electronic circuit are fabricated in advance on a surface 1a is received. The wafer 1 may be an arbitrary semiconductor wafer, for example, a silicon wafer or another compound semiconductor (as an example, a GaAs compound semiconductor) wafer. A connection terminal 3 for connecting the chip to an external circuit is formed on the surface 1a of the wafer 1 with, for example, Al. A passivation film (not shown) is generally present on the surface 1 a of the wafer 1 so that only the connection terminals 3 are exposed. In general, as a pretreatment, the back surface 1b of the wafer 1 is ground until the received wafer 1 has a predetermined thickness (for example, 200 μm), so that a new back surface 1b ′ is obtained as shown in FIG. A wafer 1 ′ is obtained.

  As shown in FIG. 1 (c), the wafer 1 ′ thus pretreated is fixed by bonding the back surface 1 b ′ to the first support 5. As the 1st support body 5, the tape marketed as an ultraviolet curing type dicing tape (UV tape) can be used, for example. This type of tape can fix the wafer with a strong adhesive force, and after separating the chip from the wafer, the chip can be separated by losing the adhesive force by irradiation with ultraviolet rays. Utilizing this characteristic, the ultraviolet curable dicing tape of the first support 1 is a wafer so as to make it easy to transfer chips individually separated from the first support to the second support. Before bonding 1 ', the adhesive strength can be lowered by irradiating with ultraviolet rays in advance.

  Next, the wafer 1 ′ bonded to the first support 5 is separated into pieces. As shown in FIG. 1 (d), a dicing blade 7 can be used for the individualization as usual. The singulation is performed such that the first support 5 is stopped when it is cut halfway, and each chip 9 thus separated can be held on the single first support 5. it can.

  Subsequently, as shown in FIG. 1E, the separated chip 9 is transferred from the first support 5 to the second support 11. When the second support 11 itself does not have an adhesive force to fix the chip 9, a coupling member 13 that can be coupled to the chip 9 is provided on the surface 11 a of the second support 11 that receives the chip 9. I can leave. When the chip 9 is transferred from the first support 5 to the second support 11, the exposed surface of the chip 9 on the first support 5 (the surface on which the connection terminal 3 is located) is used as the second support. 11, the first support 5 is peeled from the chip 9. For example, as described above, an ultraviolet curable dicing tape is used as the first support 1 and its adhesive strength is reduced by irradiating with ultraviolet rays in advance. It can be easily peeled off from the chip 9 coupled to the support 11 via the coupling member 13.

  As the second support 11, a rigid plate material such as silicon, glass, metal (for example, copper) can be used. A glass epoxy substrate used as a core substrate of the wiring substrate can also be used. The thickness of the second support 11 may be about 500 μm, for example. As the coupling member 13, for example, a double-sided type releasable ultraviolet-curing or heat-peelable tape or sheet material (for example, Nitto Denko's heat release sheet “Riva Alpha”) may be used. it can. When an ultraviolet curable material that loses adhesive strength when irradiated with ultraviolet rays is used as the coupling member 13, a glass plate that transmits ultraviolet rays is used as the second support 11.

  After peeling off the first support 5, as shown in FIG. 2A, a metal film 15 is formed on the chip 9 on the second support 1 with a thickness of about 0.5 to 1 μm, for example. . The metal film 15 can be formed by sputtering or vapor deposition. It is also possible to use a plating method. The metal film 15 is formed on the back surface and each side surface of the chip 9 except for the surface coupled to the second support 11 through the coupling member 13. The metal film 15 is generally formed as a solid film on the entire exposed surface (back surface and each side surface) of the chip 9 in this way, and although it is preferable, a patterned metal film is formed as necessary. It is also possible.

  Next, as shown in FIG. 2B, a pickup tape 17 is attached to the back surface of the chip 9 on which the metal film 15 is formed. Subsequently, in order to reduce the adhesive strength of the coupling member 13, irradiation with ultraviolet rays (when the coupling member 13 is an ultraviolet curing type) or heating (when the coupling member 13 is a thermal peeling type) is performed, and the pickup tape 17 is chipped. 9 is peeled off from the second support 11 together with the chip 9, and the chip 9 is transferred to the pickup tape 17 (FIG. 2C). As the pickup tape 17, a tape similar to the dicing tape used at the time of wafer dicing can be used.

  Thereafter, as shown in FIG. 2D, the chip 9 is picked up from the pick-up tape 17, and the chip 9 having the metal film 15 can be obtained. The pickup can be performed by a normal method. For example, the chip 9 may be pushed up from the back surface of the pick-up tape 17 with a needle (not shown), or ultraviolet irradiation (in the case of an ultraviolet curable tape) or heating (in the case of a heat-peelable tape) without using the needle. Thus, the chip 9 may be peeled off without the adhesive force of the tape.

  Thus, according to the present invention, a series of steps until picking up an individualized chip having a metal film formed on the back surface is performed in a state where the chip is fixed to the support (first or second support). Therefore, it is possible to prevent a decrease in chip yield due to breakage of the wafer during handling. Further, since it is not necessary to dice only the wafer and cut the back surface metal film together at the time of dicing, chipping of the chip cut surface and peeling of the metal film can be prevented.

  FIG. 3 shows a semiconductor chip 30 obtained by the method of the present invention. The semiconductor chip 30 includes a chip body 9 in which basic components (not shown) such as transistors and electronic circuits are formed on the front surface 1a and the connection terminals 3 are located, and a metal that covers the back surface 1b ′ and the side surface 1c. It is constituted by the film 15. The metal film 15 can be used as a back electrode of the chip 30 or can serve to reinforce the chip body 9 based on a relatively brittle semiconductor material such as silicon. It can also improve the performance. If necessary, the metal film 15 may be patterned so as to cover only a part of one or both of the back surface 1b 'and the side surface 1c of the chip body 9.

It is a figure explaining the process of the first half of the method of this invention which manufactures the semiconductor chip provided with the metal film on the back surface. It is a figure explaining the latter process of the method of this invention. It is a figure explaining the semiconductor chip obtained by the method of this invention. It is a figure explaining the conventional manufacturing method of the semiconductor chip which has a back surface metal film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 'Wafer 1a Wafer surface 1b, 1b' Wafer back surface 3 Connection terminal 5 First support body 9 Chip 11 Second support body 13 Bonding member 15 Metal film 17 Pickup tape 30 Semiconductor chip

Claims (10)

  The basic components for each chip are fabricated on the front surface. The back side of the wafer is bonded to the first support, the wafer is fixed, and the chips are separated from the wafer in the state of being bonded to the first support. Bonding the surface of the chip to a second support to transfer the chip from the first support to the second support, forming a metal film on the exposed surface of the chip on the second support, and A method for producing a semiconductor chip having a back metal film, wherein the chip is separated from the second support to obtain a chip having a back metal film.   The manufacturing method of the semiconductor chip which has a back surface metal film of Claim 1 using an ultraviolet curing dicing tape as a 1st support body.   The semiconductor chip having a back surface metal film according to claim 1 or 2, wherein a support made of a rigid material provided with a bonding member made of a material that bonds to a chip is used as a second support. Production method.   The manufacturing method of the semiconductor chip which has a back surface metal film of Claim 3 whose 2nd support body is a plate-shaped material made from a silicon | silicone, glass, or a metal material, or a glass epoxy board | substrate.   The manufacturing method of the semiconductor chip which has a back surface metal film of Claim 3 or 4 whose said coupling member is a tape or a sheet-like material of an ultraviolet curing type or a heat peeling type.   6. The method of manufacturing a semiconductor chip having a back metal film according to claim 1, wherein the metal film is formed on the entire exposed surface of the chip on the second support.   6. The method of manufacturing a semiconductor chip having a back metal film according to claim 1, wherein the metal film is formed on a part of an exposed surface of the chip on the second support.   A semiconductor chip in which basic components are formed on the front surface, connection terminals are located, and a metal film is provided on the back surface, wherein the back surface metal film extends from the back surface to the side surface of the chip. A semiconductor chip having a back metal film.   The semiconductor chip which has a back surface metal film of Claim 8 with which the said metal film has covered the whole back surface and side surface of a chip | tip.   The semiconductor chip having a back metal film according to claim 8, wherein the metal film covers only a part of one or both of the back surface and the side surface of the chip.

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