JP2009239195A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent high temperature heating of a semiconductor wafer and the occurrence of cracks in grinding, and to form a protective resin having a sufficient thickness on each side of a semiconductor chip without being damaged. <P>SOLUTION: A plurality of grooves 4 are formed in a lattice shape on one main surface 1a of the semiconductor wafer 1, a water-soluble and liquid coating resin 5 is supplied into the groove 4 by fixed depth, and the groove 4 is filled with a hydrophobic and liquid protective resin 6 from a portion on the coating resin 5. Then, the other main surface 1b of the semiconductor wafer 1 is ground until the coating resin 5 is reached, while supplying demineralized water onto one main surface 1b of the semiconductor wafer 1 including the groove 4, and the coating resin 5 remaining in the groove 4 is removed. After that, the protective resin 6 is cut along the center of the protective resin 6 for division into a plurality of semiconductor chips 3, where respective sides 3c are covered with the protective resin 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device in which a protective film can be favorably formed on a side surface of a semiconductor chip that is thinned by grinding.

  For example, in the conventional method of manufacturing a semiconductor device in which a protective film is formed on the side surface of a thin semiconductor chip, a main surface (1a) of a semiconductor wafer (1) is formed along a partition line (D) as shown in FIG. After the plurality of grooves (4) are formed in a lattice pattern by a dicer, the protective resin (6) is filled into the plurality of grooves (4) by a dispensing method or a screen printing method as shown in FIG. For example, the groove (4) having a width of the bottom (4a) of about 100 μm and a depth of about 200 μm along the side wall (4c) is formed in the semiconductor wafer (1) having a thickness of about 400 μm. As the protective resin (6), for example, a siloxane resin such as a silicone resin or a thermosetting resin such as a polyimide resin is used. Next, the semiconductor wafer (1) shown in FIG. 8 is carried into a clean oven, the protective resin (6) in the plurality of grooves (4) is heated and cured, and then the semiconductor wafer (1) is inverted, A holding tape (2) shown in FIG. 9 is attached as a holder to one main surface (1a) of the semiconductor wafer (1) so as to cover the groove (4). Then, while supplying pure water to the polishing surface, the grinding device (10) such as a grinding wheel connected to the drive device (11) is used to reach the grinding surface (G) until the protective resin (6) is exposed. The other main surface (1b) of the wafer (1) is uniformly ground. Finally, by cutting along the center of the protective resin (6), a plurality of thin semiconductor chips (3) whose side surfaces (3c) are covered with the protective resin (6) with the protective resin (6) can be obtained. For example, Patent Document 1 below discloses a method for manufacturing a thin semiconductor device in which a side surface is covered with a protective resin.

JP 2006-32598 A

  In the manufacturing method of the semiconductor device disclosed in Patent Document 1, a groove is formed in a divided region partitioned into a plurality of chip regions on the main surface of the semiconductor wafer, and a silicon oxide film is embedded in the groove on the main surface of the semiconductor wafer. After affixing the wafer-reinforcing adhesive tape and cover adhesive tape to reinforce the semiconductor wafer, the back surface opposite to the main surface of the semiconductor wafer is ground to make the semiconductor wafer thinner, and then the silicon oxide film is grooved. Various heat treatments are performed in the state of being embedded in the inside. Patent Document 1 shows a semiconductor device that manufactures a thin semiconductor chip without causing cracks, defects or warpage in a disk-shaped semiconductor wafer.

By the way, in the conventional method for manufacturing a semiconductor device, the semiconductor wafer (1) is warped or cracked in the protective resin (6) due to shrinkage of the protective resin (6) after grinding by the grinding device (10). In order to avoid this phenomenon, for example, it is necessary to fill the groove (4) of the semiconductor wafer (1) with a highly flexible protective resin (6) having a small Shore A hardness. . However, since the resin with high flexibility has low tensile strength, when the grinding device (10) comes into contact with the protective resin (6) filled in the groove (4) of the semiconductor wafer (1), the protective resin (6) As shown in FIG. 10, the protective resin (6) is scraped from the groove (4) and the side surface (3c) of the semiconductor chip (3) is exposed. For example, the groove (4) is filled with a protective resin (6) having a Shore A hardness of 15 or less after curing and a tensile strength of about 5.0 × 10 ⁵ Pa or less, and the speed is about 0.3 to 0 while rotating. When the semiconductor wafer (1) and the protective resin (6) are ground at the same time by a grinding device (10) that moves horizontally at .5 μm / s, almost all the protective resin (6) is scraped out of the groove (4). Therefore, in a conventional manufacturing method in which a semiconductor wafer (1) is thinned by grinding and then divided into a plurality of semiconductor chips (3), a protective resin (6) having a sufficient thickness without damage is applied to each semiconductor chip (3 ) Could not be formed on each side (3c).

  Accordingly, an object of the present invention is to provide a method for manufacturing a semiconductor device in which a protective resin having a sufficient thickness without damage can be formed on each side surface of a semiconductor chip.

  A method of manufacturing a semiconductor device according to the present invention includes a step of forming a plurality of grooves (4) in a lattice shape on one main surface (1a) of a semiconductor wafer (1), and a groove of water-soluble liquid coating resin (5). (4) including a step of supplying to a certain depth, a step of filling a hydrophobic liquid protective resin (6) into the groove (4) from above the coating resin (5), and a groove (4) While supplying pure water to the other main surface (1b) of the semiconductor wafer (1), the other main surface (1b) of the semiconductor wafer (1) is ground until reaching the coating resin (5), and the groove (4) The step of removing the coating resin (5) remaining inside, the protective resin (6) was cut along the center of the protective resin (6), and each side surface (3c) was coated with the protective resin (6) Dividing the semiconductor chip into a plurality of semiconductor chips (3).

  While supplying pure water, if the other main surface (1b) of the semiconductor wafer (1) is uniformly ground until it reaches the coating resin (5), the water-soluble coating resin (5) is eluted into the pure water. The semiconductor wafer (1), which is scraped from the inside of the groove (4) to the outside and heated by the frictional heat generated during grinding, is cooled with pure water, and the semiconductor wafer (1) is heated at a high temperature and cracks are generated. At the same time, the coating resin (5) can be removed by elution. The protective resin (6) disposed inside the coating resin (5) is held in the groove (4) without being damaged or scraped by grinding. Thereafter, when the protective resin (6) is cut along the center line (C), a plurality of semiconductor chips (3) whose side surfaces (3c) are covered with the protective resin (6) are obtained. Further, the coating resin (5) in the groove (4) may be removed after the other main surface (1b) of the semiconductor wafer (1) is uniformly ground until reaching the coating resin (5).

  In the present invention, high temperature heating and cracking of the semiconductor wafer during grinding can be prevented, and when dividing into a plurality of semiconductor chips by dicing, the protective resin is not damaged, and therefore sufficient for each side of each semiconductor chip. By attaching a protective resin having a thickness, a semiconductor device with a high manufacturing yield and high reliability can be manufactured.

  Hereinafter, an embodiment of a method for manufacturing a semiconductor device according to the present invention will be described with reference to FIGS. However, in FIG. 1 to FIG. 7, parts that are substantially the same as those shown in FIG. 8 to FIG.

  In the method of manufacturing the semiconductor device of the present embodiment, first, as shown in FIG. 2, a high impurity concentration N + type semiconductor region as the first semiconductor region of the first conductivity type is formed by impurity diffusion or epitaxial growth. A low impurity concentration N− type semiconductor region as a third semiconductor region of a first conductivity type and a high impurity concentration P + type semiconductor region as a second semiconductor region of a second conductivity type different from the first conductivity type A disk-shaped semiconductor wafer (1) shown in FIG. As is well known, the semiconductor wafer (1) shown in FIG. 1 is later divided into a large number of semiconductor chips (3) by dicing. In the present embodiment, the semiconductor chip (3) is shown as a general PN junction type diode structure, but the present invention is not limited to the diode, and other various semiconductor devices such as various transistors, thyristors, or triacs. It can also be applied to manufacturing.

  Subsequently, as shown in FIG. 2, the semiconductor wafer (1) is cut from one main surface (1a) of the semiconductor wafer (1) by a dicer along the grid-like partition lines (D) shown in FIG. Then, lattice-like grooves (4) are formed in the semiconductor wafer (1). In the present embodiment, by dicing with a dicer and wet etching with an etchant, for example, the groove (4) having a width of the bottom (4a) of about 80 μm to 200 μm and a depth of about 200 μm along the side wall (4c) is thickened. It is formed on a semiconductor wafer (1) having a thickness of about 400 μm. Thus, by forming the lattice-like groove (4) on one main surface (1a) of the semiconductor wafer (1), the semiconductor is formed in the region of the plurality of semiconductor chips (3) across the groove (4). A wafer (1) is defined.

  Next, as shown in FIG. 3, a water-soluble liquid coating resin (5) is applied to a certain depth of the bottom (4a) of the groove (4) using a dispenser or screen printing. As the coating resin (5), a water-soluble resin selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, ethylene oxide, polyacrylamide, or polyester can be used. An aqueous solution of alcohol (PVA) is used.

  Subsequently, as shown in FIG. 4, a hydrophobic liquid protective resin (6) is filled into the groove (4) from above the coating resin (5) using a dispenser or screen printing. As the protective resin (6), a thermosetting silicone resin or a polyimide resin is used. For example, a silicone resin having a curing temperature of about 150 ° C. and a heat resistance of 300 ° C. or more is preferable. When the hydrophobic liquid protective resin (6) is filled into the groove (4) from above the water-soluble liquid coating resin (5), a layer of the coating resin (5) is formed below the protective resin (6). Is done. Thereafter, the semiconductor wafer (1) is carried into a heating device such as a clean oven (not shown) and heated at a temperature of about 150 ° C. for 1 hour to cure the protective resin (6) in the groove (4).

  After the protective resin (6) in the groove (4) is cured, as shown in FIG. 5, the semiconductor wafer (1) is inverted and one main surface (1a) of the semiconductor wafer (1) including the groove (4) is reversed. ) Is attached with a holding tape (2) as a holding body having elasticity. As the holding tape (2), a tape material or a film material made of a resin having elasticity is used, and the holding tape (2) facing one main surface (1a) of the semiconductor wafer (1) including the groove (4). A pressure-sensitive adhesive is applied to the adhesive surface.

  Next, as shown in FIG. 5, the grinding device (10) connected to the drive device (11) is rotated on the other main surface (1b) of the semiconductor wafer (1) in the horizontal direction. 10) is moved to uniformly grind the other main surface (1b) of the semiconductor wafer (1) until the ground surface (G) is reached and the coating resin (5) in the groove (4) is exposed. Thereby, as shown in FIG. 6, the N + type semiconductor region on the other main surface (1b) side of the semiconductor wafer (1) is ground and thinned, and the protective resin (6) in the groove (4) is obtained. The upper surface of the protective resin (6) is covered with a water-soluble coating resin (5) that is divided into a plurality of semiconductor chips (3) and remains in the grooves (4). At this time, since each semiconductor chip (3) is securely held on the holding tape (2) by the adhesive force, each semiconductor chip (3) is in contact with the grinding device (10) that rotates and moves horizontally. Don't scatter. Thereafter, pure water is supplied onto the other main surface (1b) of the semiconductor wafer (1), and the water-soluble coating resin (5) remaining in the groove (4) is purified water as shown in FIG. Elute in and remove.

  Alternatively, the grinding device (10) that rotates while supplying pure water onto the other main surface (1b) of the semiconductor wafer (1) including the groove (4) is connected to the other main surface of the semiconductor wafer (1). (1b) is moved horizontally on the surface, until the ground surface (G) is reached and the coating resin (5) is exposed, and the other main surface (1b) of the semiconductor wafer (1) is uniformly ground, The coating resin (5) remaining in the groove (4) may be removed. In this case, the water-soluble coating resin (5) is eluted into the pure water, and the coating resin (5) is scraped from the inside of the groove (4) to the outside by the rotation and horizontal movement of the grinding device (10). At the same time, the semiconductor wafer (1) heated by frictional heat generated during grinding is cooled with pure water to prevent high-temperature heating and cracking of the semiconductor wafer (1), and at the same time, the coating resin with pure water. (5) is removed by elution. At this time, the protective resin (6) arranged on the inner side of the coating resin (5) is held in the groove (4) without being damaged or scraped by grinding. However, the water-soluble protective resin (5) may be eluted and removed with pure water after grinding.

  After removing the coating resin (5) in the groove (4), the protective resin (6) shown in FIG. 7 is cut along the center line (C), and the holding tape (2) is extended in the horizontal direction. A large gap is formed between the plurality of semiconductor chips (3). In this state, when the divided semiconductor chips (3) are adsorbed by the collet and removed from the holding tape (2), a plurality of thin semiconductor chips (3c) coated with the side surfaces (3c) with the protective resin (6) ( 3) is obtained.

  Embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made. For example, in the above embodiment, polyvinyl alcohol is used as the water-soluble and liquid coating resin (5), but it is made of polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, ethylene oxide, polyacrylamide or polyester. A water-soluble resin selected from the group may be used. In the above embodiment, a silicone resin is used as the hydrophobic and liquid protective resin (6), but a polyimide resin may be used. Furthermore, the present invention is not limited to the manufacture of a PN junction type diode chip, and the present invention can also be applied to the manufacture of various types of transistors or thyristors, or monolithic integrated circuits.

  The present invention can be suitably applied to the manufacture of a semiconductor device having a resin protective film that covers the side surface of a semiconductor chip that is thinned by grinding.

The perspective view which shows the state which forms a some groove | channel on one main surface of a disk-shaped semiconductor wafer in a grid | lattice form. Sectional drawing which shows the state which forms several groove | channels in one main surface of a semiconductor wafer Sectional drawing which shows the state which apply | coats water-soluble coating resin to the bottom part of several groove | channels Sectional drawing which shows the state filled with protective resin in the groove from above the coating resin Sectional drawing which shows the state which grinds the other main surface of a semiconductor wafer with a grinding device until it reaches coating resin Sectional drawing which shows the state divided | segmented into several semiconductor chips on both sides of protective resin by grinding Sectional view showing the state where the coating resin on the protective resin is eluted and removed with pure water Sectional drawing which shows the state filled with protective resin in the some groove | channel formed in one main surface of a semiconductor wafer Sectional drawing which shows the state which grinds the other main surface of a semiconductor wafer with a grinding device until it reaches protection resin Sectional drawing which shows the state in which protective resin was scraped from the plurality of grooves after grinding

Explanation of symbols

  (1) ・ ・ Semiconductor wafer, (1a) ・ ・ One main surface, (1b) ・ ・ Other main surface, (2) ・ ・ Holding tape (holder), (3) ・ ・ Semiconductor chip, (3a ) ・ ・ One main surface, (3b) ・ ・ Other main surface, (3c) ・ ・ Side, (4) ・ ・ Groove, (4a) ・ ・ Bottom, (4b) ・ ・ Bottom, (4c) ・・ Sidewall, (5) ・ ・ Coating resin, (6) ・ ・ Protective resin, (10) ・ ・ Grinding device, (11) ・ ・ Drive device, (D) ・ ・ Partition line, (G) ・ ・ Grinding Surface, (C) ...

Claims (7)

Forming a plurality of grooves in a lattice shape on one main surface of the semiconductor wafer;
Supplying a water-soluble liquid coating resin to a certain depth in the groove;
Filling the groove with a hydrophobic liquid protective resin from above the coating resin;
While supplying pure water to the other main surface of the semiconductor wafer including the groove, the other main surface of the semiconductor wafer is ground until reaching the coating resin, and the coating resin remaining in the groove is removed. Removing, and
Cutting the protective resin along the center of the protective resin, and dividing the protective resin into a plurality of semiconductor chips each covered with the protective resin. Forming a plurality of grooves in a lattice shape on one main surface of the semiconductor wafer;
Supplying a water-soluble liquid coating resin to a certain depth in the groove;
Filling the groove with a hydrophobic liquid protective resin from above the coating resin;
Removing the coating resin remaining in the groove after grinding the other main surface of the semiconductor wafer until reaching the coating resin from the other main surface of the semiconductor wafer including the groove;
Cutting the protective resin along the center of the protective resin, and dividing the protective resin into a plurality of semiconductor chips each covered with the protective resin.   The coating resin is a water-soluble resin selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, ethylene oxide, polyacrylamide or polyester, and the protective resin is a thermosetting silicone resin. 3. The method for producing a semiconductor device according to claim 1, wherein the method is a polyimide resin.   The method for manufacturing a semiconductor device according to claim 3, further comprising a step of curing the protective resin by heating the semiconductor wafer after filling the groove with the protective resin from above the coating resin.   After grinding the other main surface of the semiconductor wafer until reaching the coating resin, pure water is supplied to the other main surface of the semiconductor wafer including the groove to remove the coating resin remaining in the groove A manufacturing method of a semiconductor device according to claim 3 or 4.   6. The method according to claim 1, further comprising a step of attaching an elastic holding body to one main surface of the semiconductor wafer including the groove before grinding the other main surface of the semiconductor wafer. A manufacturing method of the semiconductor device described in 1.   Before forming a plurality of grooves on one main surface of the semiconductor wafer, a first semiconductor region having a first conductivity type and a second conductivity type different from the first conductivity type The manufacturing method of the semiconductor device of any one of Claims 1-6 including the process of forming the semiconductor area | region of this in the said semiconductor wafer.

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