JP4126392B2 - Manufacturing method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device having columnar electrodes.
[0002]
[Prior art]
A conventional semiconductor device is called a CSP (chip size package), and has a columnar electrode formed on a connection pad portion of a rewiring formed on a semiconductor substrate (see, for example, Patent Document 1). In this case, since the columnar electrode usually has a height of 100 to 150 μm, a negative dry photoresist film with high accuracy and high transmissivity is used as a method for forming the columnar electrode. The negative dry photoresist film is adhered to the semiconductor substrate on which the rewiring is formed, and a plating resist film having an opening reaching the rewiring is formed in the columnar electrode formation region by photolithography technology. A method is used in which electrolytic plating is performed using the resist film as a mask to form columnar electrodes in the openings of the plating resist film, and then the plating resist film is peeled off.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 5-218042
[Problems to be solved by the invention]
By the way, in the semiconductor device manufacturing method as described above, when the plating resist film is formed of a negative dry photoresist film and the plating resist film is peeled off by a dipping method or a shower method using a resist stripping solution, Since the adhesion of the plating resist film made of a negative dry photoresist film is high, resist residues may occur on the outer peripheral surface of the base part of the columnar electrode and on the connection pad part upper surface and the rewiring side surface in the periphery. found. Resist residue remains in close contact with the columnar electrode and the side surface of the rewiring. If this resist residue remains, it causes etching failure during etching of the underlying metal layer and causes a short circuit between the wirings. There was a problem that a problem occurred in sex. In this case, a negative dry photoresist film has been used conventionally, but when forming a columnar electrode, a thick dry photoresist film is used in particular, and a space between wirings under the columnar electrode is narrow. This may be caused by difficulty in peeling due to the above.
Accordingly, an object of the present invention is to provide a semiconductor device manufacturing method capable of removing a resist residue generated when a plating resist film for forming a columnar electrode is peeled off.
[0005]
[Means for Solving the Problems]
According to one aspect of the present invention, the underlying metal layer is formed on a semiconductor substrate, on the upper surface of the lower ground metal interconnection layer is formed, the wiring layer have a connection pad portion, negative type dry photo By using a resist film, a step of forming a plating resist film having an opening in a region corresponding to the connection pad portion, and electrolytic plating using the plating resist film as a mask, the inside of the opening of the plating resist film A step of forming a columnar electrode on the connection pad portion, a step of stripping the plating resist film using a resist stripping solution, and a resist residue remaining on the outer peripheral surface of the base portion of the columnar electrode are removed using steam. And a step of removing the underlying metal layer after removing the resist residue .
According to a second aspect of the present invention, in the first aspect of the present invention, the resist residue removing step is performed by spraying steam at 120 ° C. or higher onto the resist residue.
The invention according to claim 3 is the invention according to claim 1, wherein the steam is any one of water vapor, alcohol water vapor, and ethanol water vapor.
The invention of claim 4 is the invention according to claim 1, between and after the pre-Symbol resist residue removal step the underlying metal layer removing step, it is characterized in that performing the washing.
And according to this invention, since it has the process of removing the resist residue which remain | survives in the base part outer peripheral surface of a columnar electrode, the resist residue generate | occur | produced when peeling the plating resist film for forming a columnar electrode is removed. be able to.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a sectional view of a semiconductor device manufactured by a manufacturing method as one embodiment of the present invention. This semiconductor device includes a silicon substrate (semiconductor substrate) 1. An integrated circuit (not shown) is provided at the center of the upper surface of the silicon substrate 1, and a plurality of connection pads 2 made of aluminum-based metal are provided connected to the integrated circuit at the periphery of the upper surface.
[0007]
An insulating film 3 made of silicon oxide, silicon nitride, or the like and a protective film 4 made of polyimide, benzocyclobutene (BCB), or the like are provided on the upper surface of the silicon substrate 1 excluding the central portion of the connection pad 2. The central portion of the connection pad 2 is exposed through an opening 5 provided in the insulating film 3 and the protective film 4.
[0008]
A base metal layer 6 is provided from the upper surface of the connection pad 2 exposed through the opening 5 to a predetermined location on the upper surface of the protective film 4. A rewiring 7 made of copper is provided on the upper surface of the base metal layer 6. A connection pad portion having a larger area than the connection pad 2 is formed at the tip of the rewiring 7, and a columnar electrode 8 made of copper is provided on the upper surface of the connection pad portion.
[0009]
A sealing film 9 made of an epoxy resin or the like is provided on the upper surface of the protective film 4 including the rewiring 7 so that the upper surface is flush with the upper surface of the columnar electrode 8. Therefore, the upper surface of the columnar electrode 8 is exposed. A solder ball 10 is provided on the upper surface of the exposed columnar electrode 8.
[0010]
Next, an example of a method for manufacturing this semiconductor device will be described. First, as shown in FIG. 2, a connection pad 2 made of an aluminum-based metal is formed on the upper surface of a silicon substrate 1 in a wafer state, and an insulating film made of silicon oxide or the like in a region excluding the central portion of the connection pad 2 on the upper surface. 3 and a protective film 4 made of polyimide or the like, and the underlying metal layer 6 is formed on the upper surface of the protective film 4 including the upper surface of the connection pad 2 exposed through the openings 5 formed in the insulating film 3 and the protective film 4. In which a rewiring 7 made of copper is formed at a predetermined position on the upper surface of the base metal layer 6 is prepared.
[0011]
Next, as shown in FIG. 3, a negative dry photoresist film is brought into intimate contact with the upper surface of the underlying metal layer 6 including the rewiring 7, and a plating resist film 11 is patterned using a photolithography technique. In this case, an opening 12 is formed in the plating resist film 11 in a region corresponding to the connection pad portion of the rewiring 7. Next, the columnar electrode 8 is formed on the upper surface of the connection pad portion of the rewiring 7 in the opening 12 of the plating resist film 11 by performing electrolytic plating of copper using the base metal layer 6 as a plating current path.
[0012]
Next, the plating resist film 11 is stripped by a dipping method or a shower method using a resist stripping solution. In this case, since the adhesion of the plating resist film 11 made of a negative dry photoresist film is high, as shown in FIG. 4, the outer peripheral surface of the base portion of the columnar electrode 8 and the upper surface of the connection pad portion of the rewiring 7 around the periphery. Resist residue 13 is generated (and possibly the side surface of rewiring 7).
[0013]
Here, as shown in FIG. 10, the peel adhesive strength of the plating resist film 11 made of a negative dry photoresist film decreases when the temperature becomes 120 ° C. or higher. Therefore, next, when water vapor of 120 ° C. or higher is sprayed onto the silicon substrate 1 including the resist residue 13 by a shower method or the like, the adhesive strength of the resist residue 13 is reduced, and the resist residue 13 is removed.
[0014]
In this case, a part of the resist residue 13 may be caught on the outer peripheral surface of the base portion of the columnar electrode 8 or on the connection pad portion of the rewiring 7 around the periphery. However, since the resist residue 13 that has been caught is once heated to 120 ° C. or higher, its adhesive strength is extremely weak and can be easily and reliably removed by washing with water or ultrasonic water.
[0015]
Next, when unnecessary portions of the base metal layer 6 are removed by etching using the rewiring 7 as a mask, the base metal layer 6 remains only under the rewiring 7 as shown in FIG. Next, as shown in FIG. 6, the sealing film 9 made of epoxy resin or the like is formed on the upper surface of the protective film 4 including the columnar electrode 8 and the rewiring 7 so that its thickness is slightly larger than the height of the columnar electrode 8. To form. In this state, the upper surface of the columnar electrode 8 is covered with the sealing film 9.
[0016]
Next, the upper surfaces of the columnar electrodes 8 are exposed by appropriately polishing the upper surfaces of the sealing film 9 and the columnar electrodes 8 as shown in FIG. Next, as shown in FIG. 8, solder balls 10 are formed on the upper surfaces of the columnar electrodes 8. Next, as shown in FIG. 9, after a dicing process, a plurality of semiconductor devices shown in FIG. 1 are obtained.
[0017]
In the semiconductor device obtained in this way, the resist residue 13 remaining on the outer peripheral surface of the base portion of the columnar electrode 8 and the connection pad portion of the rewiring 7 in the periphery thereof can be completely removed. Can be improved.
[0018]
In the above embodiment, the case where water vapor of 120 ° C. or higher is used to remove the resist residue 13 is not limited to this, but alcohol vapor such as ethanol vapor of 120 ° C. or higher may be used. In this case, in particular, when ethanol vapor is used, since ethanol has the ability to dissolve a plating resist film made of a negative dry photoresist film, the resist residue removal performance can be improved as compared with the case of water vapor.
[0019]
In the above embodiment, the columnar electrode is formed on the connection pad portion of the rewiring 7. However, in the present invention, the columnar electrode is formed on the connection pad portion of the semiconductor substrate where the rewiring is not formed. It can also be applied to the formation.
[0020]
【The invention's effect】
As described above, according to the present invention, since the resist residue remaining on the outer peripheral surface of the base part of the columnar electrode is removed, the resist generated when the plating resist film for forming the columnar electrode is peeled off. The residue can be removed, and the reliability can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a semiconductor device manufactured by a manufacturing method as one embodiment of the present invention.
FIG. 2 is a cross-sectional view of an initial manufacturing process in manufacturing the semiconductor device shown in FIG. 1;
FIG. 3 is a cross-sectional view of the manufacturing process following FIG. 2;
FIG. 4 is a cross-sectional view of the manufacturing process following FIG. 3;
FIG. 5 is a cross-sectional view of the manufacturing process following FIG. 4;
6 is a cross-sectional view of the manufacturing process following FIG. 5. FIG.
7 is a cross-sectional view of a manufacturing step that follows FIG. 6. FIG.
FIG. 8 is a cross-sectional view of the manufacturing process following FIG. 7;
FIG. 9 is a cross-sectional view of the manufacturing process following FIG. 8;
FIG. 10 is a diagram showing a relationship between peel adhesive strength and temperature of a plating resist film made of a negative dry photoresist film.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Connection pad 3 Insulating film 4 Protective film 5 Opening part 6 Base metal layer 7 Rewiring 8 Columnar electrode 9 Sealing film 10 Solder ball 11 Plating resist film 13 Resist residue

Claims (4)

Is the underlying metal layer is formed on a semiconductor substrate, the upper surface of the lower ground metal interconnection layer is formed, the wiring layer have a connection pad portion, with a dry photoresist film negative, the connection pad Forming a plating resist film having an opening in a region corresponding to the portion, and performing electrolytic plating using the plating resist film as a mask to form a columnar electrode on the connection pad portion in the opening of the plating resist film A step of forming, a step of removing the plating resist film using a resist stripping solution, a step of removing the resist residue remaining on the outer peripheral surface of the base portion of the columnar electrode using steam, and the resist residue being removed And a step of removing the base metal layer afterwards .   2. The method of manufacturing a semiconductor device according to claim 1, wherein the resist residue removing step is performed by spraying steam at 120 [deg.] C. or higher onto the resist residue. In the invention of claim 1, wherein the vapor is water vapor, alcohol vapor, a method of manufacturing a semiconductor device which is characterized in that either ethanol vapor. 2. The method of manufacturing a semiconductor device according to claim 1 , wherein water washing is performed between the resist residue removing step and the base metal layer removing step.

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