JP2009289863A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device which has a sealing film provided around a columnar electrode, and in which transverse rupture strength is made higher even when a silicon substrate is reduced in thickness. <P>SOLUTION: The sealing film 11 provided around the columnar electrode 10 is formed of a material obtained by impregnating a base made of glass fiber, glass cloth, aramid fiber, aramid cloth, etc., or a composite base thereof with a thermosetting resin composed of an epoxy resin etc. Consequently, the transverse rupture strength is made higher even when the silicon substrate 1 is reduced in thickness as compared with a case wherein the sealing film 11 is formed of a material prepared by mixing silica particles with an epoxy resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  A conventional semiconductor device is generally called a CSP (chip size package). A wiring is provided on a semiconductor substrate, a columnar electrode is provided on an upper surface of a connection pad portion of the wiring, and a periphery of the columnar electrode is sealed with a sealing film. (For example, refer to Patent Document 1). In this case, in order to reduce the stress caused by the difference in thermal expansion coefficient between the semiconductor substrate and the sealing film, a part of the sealing film is formed of a material in which silica particles are mixed in an epoxy resin.

JP 2000-22052 A

  By the way, in the conventional semiconductor device described above, a part of the sealing film is formed of a material in which silica particles are mixed in an epoxy resin. Folding strength can be increased to some extent. However, if the thickness of the semiconductor substrate is reduced in order to reduce the thickness of the semiconductor device, there is a limit to the bending strength even if the entire sealing film is formed of a material in which silica particles are mixed in an epoxy resin. There was a problem that there was.

  Therefore, an object of the present invention is to provide a method for manufacturing a semiconductor device, which can further increase the bending strength even if the thickness of the semiconductor substrate is reduced.

According to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: preparing a semiconductor wafer having a plurality of columnar electrodes formed thereon; and forming a substrate or a composite on the semiconductor wafer including the columnar electrodes. Forming a sealing film made of a material in which a base material is impregnated with a thermosetting resin or an ultraviolet curable resin, and grinding or polishing an upper surface side of the sealing film to expose an upper surface of the columnar electrode And a step of cutting the semiconductor wafer and the sealing film to obtain a plurality of semiconductor devices.
According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device comprising: a step of preparing a semiconductor wafer having a plurality of columnar electrodes formed thereon; and a substrate or a composite on the semiconductor wafer including the columnar electrodes. Forming a sealing film made of a material in which a base material is impregnated with a thermosetting resin or an ultraviolet curable resin, and forming an opening in the sealing film in a portion corresponding to a part of the upper surface of the columnar electrode And a step of cutting the semiconductor wafer and the sealing film to obtain a plurality of semiconductor devices.
According to a third aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the first or second aspect of the present invention, wherein the step of forming the sealing film includes forming a base material on the semiconductor wafer including the columnar electrode. Alternatively, the composite substrate is impregnated with a thermosetting resin or an ultraviolet curable resin, and a sheet for forming a sealing film in which the thermosetting resin or the ultraviolet curable resin is in a semi-cured state is disposed and heated. It includes a step of flowing the thermosetting resin or the ultraviolet curable resin in the sealing film forming sheet by pressurization or ultraviolet irradiation.
According to a fourth aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the first or second aspect of the present invention, further comprising a step of grinding or polishing a back surface of the semiconductor wafer before the cutting step. It is what.
According to a fifth aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the first aspect of the present invention, comprising the step of forming a solder ball on the upper surface of the columnar electrode before the cutting step. To do.
According to a sixth aspect of the present invention, in the semiconductor device manufacturing method according to the second aspect of the present invention, the step of forming the opening in the sealing film may be performed by laser processing by laser beam irradiation or by using a mechanical drill. It is characterized by being used.
According to a seventh aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the second aspect of the present invention, comprising the step of forming solder balls in and above the opening of the sealing film before the cutting step. It is characterized by having.
According to an eighth aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the second aspect of the present invention, wherein, before the cutting step, a protruding electrode is formed by electroless plating in and above the opening of the sealing film. It has the process of forming, It is characterized by the above-mentioned.
According to a ninth aspect of the present invention, in the semiconductor device manufacturing method according to the second aspect of the present invention, the metal film is formed in the opening of the sealing film before the cutting step, and the metal film is formed on the metal film. And a step of forming a protruding electrode.
According to a tenth aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the ninth aspect, wherein the protruding electrode has a conical shape.

  According to this invention, since the sealing film is formed of the material in which the base material or the composite base material is impregnated with the thermosetting resin or the ultraviolet curable resin, the sealing is performed with the material in which the silica particles are mixed in the epoxy resin. Even if the thickness of the semiconductor substrate is reduced as compared with the case where the stop film is formed, the bending strength can be further increased.

(First embodiment)
FIG. 1 shows a cross-sectional view of a semiconductor device manufactured by the manufacturing method according to the first embodiment of the present invention. This semiconductor device is generally called a CSP and includes a silicon substrate (semiconductor substrate) 1. An integrated circuit (not shown) having a predetermined function is provided on the upper surface of the silicon substrate 1, and a plurality of connection pads 2 made of aluminum-based metal or the like are provided on the periphery of the upper surface so as to be connected to the integrated circuit.

  An insulating film 3 made of silicon oxide or the like is provided on the upper surface of the silicon substrate 1 excluding the central portion of the connection pad 2, and the central portion of the connection pad 2 is exposed through an opening 4 provided in the insulating film 3. Yes. A protective film 5 made of polyimide resin or the like is provided on the upper surface of the insulating film 3. An opening 6 is provided in the protective film 5 at a portion corresponding to the opening 4 of the insulating film 3.

  A wiring 7 is provided on the upper surface of the protective film 5. The wiring 7 has a two-layer structure of a base metal layer 8 made of copper or the like provided on the upper surface of the protective film 5 and an upper metal layer 9 made of copper provided on the upper surface of the base metal layer 8. One end of the wiring 7 is connected to the connection pad 2 through the openings 4 and 6 of the insulating film 3 and the protective film 5. A columnar electrode 10 made of copper is provided on the upper surface of the connection pad portion of the wiring 7.

  A sealing film 11 is provided on the upper surface of the protective film 5 including the wiring 7, that is, around the columnar electrode 10 so that the upper surface thereof is flush with the upper surface of the columnar electrode 10. The sealing film 11 is made of a material in which a base material made of glass fiber, glass cloth, aramid fiber, aramid cloth or the like or a composite base material thereof is impregnated with a thermosetting resin made of a thermosetting epoxy resin or the like. ing. A solder ball 12 is provided on the upper surface of the columnar electrode 10.

  As described above, in this semiconductor device, the sealing film 11 is formed by thermosetting a base material made of glass fiber, glass cloth, aramid fiber, aramid cloth or the like or a composite base material made of thermosetting epoxy resin or the like. Since the sealing film 11 is formed of a material impregnated with a conductive resin, the thickness of the silicon substrate 1 can be reduced compared to the case where the sealing film 11 is formed of a material in which silica particles are mixed in an epoxy resin. The bending strength can be further increased.

  Next, an example of a method for manufacturing this semiconductor device will be described. First, as shown in FIG. 2, on a silicon substrate in a wafer state (hereinafter referred to as a semiconductor wafer 21), a connection pad 2 made of aluminum metal or the like, an insulating film 3 made of silicon oxide or the like, a protection made of polyimide resin or the like. A film 5, wiring 7 (a base metal layer 8 made of copper and an upper metal layer 9 made of copper) and a columnar electrode 10 made of copper are prepared.

  In this case, an integrated circuit having a predetermined function is formed in a region of the semiconductor wafer 21 where each semiconductor device is formed, and the connection pads 2 are electrically connected to the integrated circuits formed in the corresponding regions. Further, the thickness of the semiconductor wafer 21 is somewhat thicker than the thickness of the silicon substrate 1 shown in FIG. In FIG. 2, an area indicated by reference numeral 22 is an area corresponding to dicing street.

  Next, as shown in FIG. 3, the sealing film forming sheet 11 a is disposed on the upper surfaces of all the columnar electrodes 10. The sealing film forming sheet 11a impregnates a base material made of glass fiber, glass cloth, aramid fiber, aramid cloth or the like or a composite base material thereof with a thermosetting resin made of a thermosetting epoxy resin or the like, The thermosetting resin is made into a semi-cured state to form a sheet. Next, the release film 23 is arrange | positioned on the upper surface of the sheet | seat 11a for sealing film formation.

  Next, as shown in FIG. 4, the sealing film forming sheet 11 a is heated and pressurized from above and below using a pair of heating and pressing plates 24 and 25. By this heating and pressing, the thermosetting resin in the sealing film forming sheet 11 a flows, and the sealing film 11 has a thickness of the columnar electrode 10 on the upper surface of the protective film 5 including the wiring 7 and the columnar electrode 10. It is formed to be thicker than the height. Therefore, in this state, the upper surface of the columnar electrode 10 is covered with the sealing film 11.

  In this case, the release film 23 reliably prevents unnecessary adhesion of the thermosetting resin made of fluidized epoxy resin or the like in the sealing film forming sheet 11a to the lower surface of the upper heating and pressing plate 24. The upper heating and pressure plate 24 can be reused as it is.

  Next, the upper surface side of the sealing film 11 is appropriately ground or polished so that the upper surface of the columnar electrode 10 is exposed and the sealing film including the exposed upper surface of the columnar electrode 10 as shown in FIG. 11 is flattened. Here, in the method of forming the sealing film 11 using the sealing film forming sheet 11a, a method of forming a sealing film by applying and curing a liquid resin by a printing method (hereinafter referred to as a printing method). As compared with the above, it is easy to control the thickness of the sealing film 11 in the state of FIG.

  Therefore, the thickness of the sealing film 11 on the columnar electrode 10 in the state of FIG. 4 can be reduced as compared with the printing method. As a result, as compared with the printing method, the grinding or polishing time on the upper surface side of the sealing film 11 can be shortened, and stress on the semiconductor wafer 21 accompanying the grinding or polishing on the upper surface side of the sealing film 11 can be reduced. The amount of sealing resin used can be further reduced.

  Next, as shown in FIG. 6, in order to reduce the thickness of the semiconductor wafer 21, the lower surface (back surface) of the semiconductor wafer 21 is appropriately ground or polished. Next, as shown in FIG. 7, solder balls 12 are formed on the upper surface of the columnar electrode 10. Next, as shown in FIG. 8, when the sealing film 11, the protective film 5, the insulating film 3 and the semiconductor wafer 21 are cut along the dicing street 22, a plurality of semiconductor devices shown in FIG. 1 are obtained.

(Second Embodiment)
FIG. 9 is a sectional view of a semiconductor device manufactured by the manufacturing method according to the second embodiment of the present invention. This semiconductor device is different from the semiconductor device shown in FIG. 1 in that the upper surface of the sealing film 11 is made higher than the upper surface of the columnar electrode 10 and the sealing film 11 in the portion corresponding to the center of the upper surface of the columnar electrode 10 is used. The opening 13 is provided, and the solder ball 12 is connected to the upper surface of the columnar electrode 10 in and above the opening 13 of the sealing film 11.

  Next, an example of a method for manufacturing this semiconductor device will be described. In this case, after the step shown in FIG. 4, as shown in FIG. 10, the sealing film 11 in the portion corresponding to the central portion of the upper surface of the columnar electrode 10 is subjected to laser processing by laser beam irradiation or using a mechanical drill. Opening 13 is formed. In this case, compared with the printing method, the thickness of the sealing film 11 on the columnar electrode 10 in the state shown in FIG. 4 can be reduced, so that the time for forming the opening 13 can be shortened.

  Next, although not shown, the back surface of the semiconductor wafer 21 is appropriately ground or polished. Next, a solder ball 12 is formed in the opening 13 of the sealing film 11 and above it by connecting it to the upper surface of the columnar electrode 10. In this case, when the spherical solder ball that is the base of the solder ball 12 is arranged, it is possible to make it difficult for the spherical solder ball that has once entered the opening 13 of the sealing film 11 to come out. Next, through a dicing process, a plurality of semiconductor devices shown in FIG. 9 are obtained.

  By the way, in this method for manufacturing a semiconductor device, the upper surface side of the sealing film 11 is ground or polished only by forming the opening 13 in the sealing film 11 in the portion corresponding to the center of the upper surface of the columnar electrode 10. Since it is not performed at all, the stress on the semiconductor wafer 21 due to grinding or polishing of the upper surface side of the sealing film 11 can be eliminated.

(Third embodiment)
FIG. 11 is a sectional view of a semiconductor device manufactured by the manufacturing method according to the third embodiment of the present invention. This semiconductor device is different from the semiconductor device shown in FIG. 9 in that a mushroom-shaped protruding electrode 14 is connected to the upper surface of the columnar electrode 10 by electroless plating of copper in and above the opening 13 of the sealing film 11. It is a point that was provided.

  Next, an example of a method for manufacturing this semiconductor device will be described. In this case, after the step shown in FIG. 10, although not shown, the back surface of the semiconductor wafer 21 is appropriately ground or polished. Next, a mushroom-shaped protruding electrode 14 is formed on the upper surface of the columnar electrode 10 in and above the opening 13 of the sealing film 11 by electroless plating of copper. Next, through a dicing process, a plurality of semiconductor devices shown in FIG. 11 are obtained.

  The material of the protruding electrode 14 may be tin-silver. In this case, the protruding electrode 14 may be formed by tin-silver electroless plating. First, the diffusion preventing layer is formed on the upper surface of the columnar electrode 10 in the opening 13 of the sealing film 11 by electroless plating of nickel. Then, a protruding electrode may be formed thereon by tin-silver electroless plating.

(Fourth embodiment)
FIG. 12 is a sectional view of a semiconductor device manufactured by the manufacturing method according to the fourth embodiment of the present invention. This semiconductor device is different from the semiconductor device shown in FIG. 9 in that a metal film 15 made of copper or the like is provided on the upper surface of the columnar electrode 10 in the opening 13 of the sealing film 11, and copper or the like is formed on the upper surface of the metal film 15. This is a point in which a conical protruding electrode 16 is provided.

  Next, an example of a method for manufacturing this semiconductor device will be described. In this case, after the step shown in FIG. 10, although not shown, the back surface of the semiconductor wafer 21 is appropriately ground or polished. Next, the metal film 15 is formed on the upper surface of the columnar electrode 10 in the opening 13 of the sealing film 11. As a method for forming the metal film 15, there is a method in which a metal nano ink containing metal particles made of copper having a particle size of nano order is applied by an ink jet head and baked. In this case, since the inner wall surface of the opening 13 of the sealing film 11 functions as a weir, unnecessary outflow of the metal nano ink to the upper surface of the sealing film 11 can be prevented.

  Next, a plurality of conical recesses provided on the lower surface of the mold (not shown) in which the protruding electrodes 16 made of copper or the like are formed are used. The formed protruding electrode 16 is metal-bonded to the upper surface of the metal film 15. Next, through a dicing process, a plurality of semiconductor devices shown in FIG. 12 are obtained.

(Other embodiments)
In each of the above-described embodiments, as the sealing film forming sheet 11a, a base material made of glass fiber, glass cloth, aramid fiber, aramid cloth or the like, or a thermosetting type epoxy resin or the like on a composite base material thereof. Although the case where the thermosetting resin was impregnated and the thermosetting resin was made into a semi-cured state and used as a sheet was described, it is not limited to this.

  For example, as the sealing film forming sheet 11a, a base material made of glass fiber, glass cloth, aramid fiber, aramid cloth or the like or a composite base material thereof is impregnated with an ultraviolet curable resin made of an ultraviolet curable epoxy resin or the like. It is also possible to use an ultraviolet curable resin in a semi-cured state to form a sheet.

  In this case, the UV curable epoxy resin or the like may be cured only by UV irradiation, but the in-plane uniformity of curing of the UV curable epoxy resin or the like is improved to improve the film thickness accuracy. For this purpose, first, temporary curing may be performed by irradiation with ultraviolet rays, and then main curing may be performed by irradiation with infrared rays or heating using a heating furnace.

Sectional drawing of the semiconductor device manufactured by the manufacturing method as 1st Embodiment of this invention. Sectional drawing of what was initially prepared in an example of the manufacturing method of the semiconductor device shown in FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the semiconductor device manufactured by the manufacturing method as 2nd Embodiment of this invention. Sectional drawing of a predetermined | prescribed process in an example of the manufacturing method of the semiconductor device shown in FIG. Sectional drawing of the semiconductor device manufactured by the manufacturing method as 3rd Embodiment of this invention. Sectional drawing of the semiconductor device manufactured by the manufacturing method as 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Connection pad 3 Insulating film 5 Protective film 7 Wiring 10 Columnar electrode 11 Sealing film 12 Solder ball 13 Opening 14 Projection electrode 15 Metal film 16 Projection electrode 21 Semiconductor wafer 22 Dicing street

Claims (10)

Preparing a plurality of columnar electrodes formed on a semiconductor wafer;
Forming a sealing film made of a material obtained by impregnating a base material or a composite base material with a thermosetting resin or an ultraviolet curable resin on the semiconductor wafer including the columnar electrodes;
Grinding or polishing the upper surface side of the sealing film to expose the upper surface of the columnar electrode;
Cutting the semiconductor wafer and the sealing film to obtain a plurality of semiconductor devices;
A method for manufacturing a semiconductor device, comprising: Preparing a plurality of columnar electrodes formed on a semiconductor wafer;
Forming a sealing film made of a material obtained by impregnating a base material or a composite base material with a thermosetting resin or an ultraviolet curable resin on the semiconductor wafer including the columnar electrodes;
Forming an opening in the sealing film in a portion corresponding to a part of the upper surface of the columnar electrode;
Cutting the semiconductor wafer and the sealing film to obtain a plurality of semiconductor devices;
A method for manufacturing a semiconductor device, comprising:   3. The invention according to claim 1, wherein the step of forming the sealing film includes impregnating a base material or a composite base material with a thermosetting resin or an ultraviolet curable resin on the semiconductor wafer including the columnar electrode. A sealing film forming sheet in the form of a sheet in a semi-cured state of the thermosetting resin or the ultraviolet curable resin, and by heating and pressing or ultraviolet irradiation, A method of manufacturing a semiconductor device, comprising a step of flowing a thermosetting resin or the ultraviolet curable resin.   3. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of grinding or polishing a back surface of the semiconductor wafer before the cutting step.   2. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of forming a solder ball on an upper surface of the columnar electrode before the cutting step.   3. The method for manufacturing a semiconductor device according to claim 2, wherein the step of forming the opening in the sealing film is performed by laser processing by laser beam irradiation or using a mechanical drill.   3. The method of manufacturing a semiconductor device according to claim 2, further comprising a step of forming solder balls in and above the opening of the sealing film before the cutting step.   3. The method of manufacturing a semiconductor device according to claim 2, further comprising a step of forming a protruding electrode by electroless plating in and above the opening of the sealing film before the cutting step.   3. The semiconductor device according to claim 2, further comprising a step of forming a metal film in the opening of the sealing film and forming a protruding electrode on the metal film before the cutting step. Manufacturing method.   10. The method of manufacturing a semiconductor device according to claim 9, wherein the protruding electrode has a conical shape.

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