JP2007294558A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a crack from occurring at an interface between a columnar electrode and a solder ball in a semiconductor device in which solder balls are formed on the columnar electrode.
A columnar electrode 9 includes a metal spherical body 10 partially protruding above the sealing film 12, and a plated portion provided around the metal spherical body 10 below the upper surface of the sealing film 12. 11. In this case, the metal spherical body 10 protruding above the sealing film 12 bites into the solder ball 13, thereby making it difficult for cracks to occur at the interface between the columnar electrode 9 and the solder ball 13.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor device having columnar electrodes and a method for manufacturing the same.

  A conventional semiconductor device is called a CSP (chip size package). A wiring is provided on an upper surface of an insulating film provided on a semiconductor substrate, and a columnar electrode is provided on an upper surface of a connection pad portion of the wiring. In some cases, a sealing film is provided on the upper surface of the insulating film to be included so that the upper surface is flush with the upper surface of the columnar electrode, and a solder ball is provided on the upper surface of the columnar electrode (see, for example, Patent Document 1).

JP 2004-349461 A

  However, in the above conventional semiconductor device, solder balls are provided on the upper surface of the columnar electrode that is flush with the upper surface of the sealing film. Therefore, after mounting the semiconductor device on the circuit board, a temperature cycle test or the like is performed. When performed, there is a problem that cracks may occur at the interface between the columnar electrode and the solder ball due to the stress generated due to the difference in thermal expansion coefficient between the semiconductor substrate and the circuit substrate.

  In view of the above, an object of the present invention is to provide a semiconductor device and a method for manufacturing the same that can prevent cracks from occurring at the interface between the columnar electrode and the solder ball.

In order to achieve the above object, a semiconductor device according to claim 1 is provided with a semiconductor substrate, a plurality of columnar electrodes provided on the semiconductor substrate, and provided around the columnar electrodes on the semiconductor substrate. In a semiconductor device having a sealing film and a solder ball provided on the columnar electrode, the columnar electrode includes a metal member partially protruding above the sealing film and a lower surface than the upper surface of the sealing film. It consists of the plating part provided in the circumference | surroundings of the said metal member in the side.
A method of manufacturing a semiconductor device according to claim 7 includes a step of forming a base metal layer on the entire surface of a semiconductor substrate, a step of forming a wiring on the base metal layer, and the base including the wiring. Forming a plating resist film having an opening in a portion corresponding to the connection pad portion of the wiring on the metal layer; and disposing a metal member on the connection pad portion of the wiring in the opening of the plating resist film And by performing electrolytic plating using the base metal layer as a plating current path, a plating portion is placed around the metal member on the upper side of the plating portion on the connection pad portion of the wiring in the opening of the plating resist film. Forming a part of the metal member so as to protrude, forming a columnar electrode with the metal member and the plated portion, peeling the plating resist film, and under the wiring. Removing the base metal layer, forming a sealing film on the semiconductor substrate including the wiring and the columnar electrode, and exposing the upper surface of the columnar electrode on the upper surface side of the sealing film. Etching and removing, and forming a solder ball on the upper surface of the columnar electrode.

  According to this invention, the columnar electrode is composed of a metal member partially protruding above the sealing film and a plated portion provided around the metal member below the upper surface of the sealing film. Therefore, the metal member protruding above the sealing film bites into the solder ball, thereby making it difficult for cracks to occur at the interface between the columnar electrode and the solder ball.

(First embodiment)
FIG. 1 is a sectional view of a semiconductor device as a first embodiment of the present invention. This semiconductor device 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 (insulating 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 base metal layer 7 made of copper or the like is provided on the upper surface of the protective film 5. A wiring 8 made of copper is provided on the entire upper surface of the base metal layer 7. One end of the wiring 8 including the base metal layer 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 9 is provided on the upper surface of the connection pad portion of the wiring 8. The columnar electrode 9 has a structure in which a plated portion 11 made of copper is provided around a metal sphere 10 made of copper or the like, and a part of the metal sphere 10 protrudes above the plated portion 11. . In this case, the outer shape of the plating part 11 is a planar circular shape. The diameter of the metal spherical body 10 is somewhat smaller than the diameter of the plated portion 11.

  A sealing film 11 made of an epoxy resin or the like is provided on the upper surface of the protective film 5 including the wiring 8 so that the upper surface is substantially flush with the upper surface of the plated portion 11 of the columnar electrode 9. Therefore, the metal spherical body 10 protruding from the upper surface of the plated portion 11 of the columnar electrode 9 protrudes above the sealing film 12. Solder balls 13 are provided on the upper surface of the columnar electrode 9, that is, the upper surface of the plated portion 11 including the metal spherical body 10.

  Thus, in this semiconductor device, the columnar electrode 9 includes a metal sphere (metal member) 10 that partially protrudes above the sealing film 12 and a metal sphere on the lower side of the upper surface of the sealing film 12. 10, the metal spherical body 10 protruding above the sealing film 12 bites into the solder ball 13, and thereby the columnar electrode 9 and the solder ball 13 It is possible to prevent the occurrence of cracks at the interface.

  Next, an example of a method for manufacturing this semiconductor device will be described. First, as shown in FIG. 2, the upper surface of a silicon substrate in a wafer state (hereinafter referred to as a semiconductor wafer 21) is formed of a connection pad 2 made of aluminum metal, an insulating film 3 made of silicon oxide, and a polyimide resin. The protective film 5 is formed, and the connection pad 2 is exposed through the openings 4 and 6 formed in the insulating film 3 and the protective film 5.

  In this case, an integrated circuit (not shown) having a predetermined function is formed in a region where each semiconductor device is formed on the upper surface of the semiconductor wafer 21, and the connection pad 2 is electrically connected to the integrated circuit formed in the corresponding region. Connected. In FIG. 2, an area indicated by reference numeral 22 is an area corresponding to a dicing line.

  Next, as shown in FIG. 3, a base metal layer 7 is formed on the entire upper surface of the protective film 5 including the upper surfaces of the connection pads 2 exposed through the openings 4 and 6 of the insulating film 3 and the protective film 5. . In this case, the base metal layer 7 may be only a copper layer formed by electroless plating, or may be only a copper layer formed by sputtering, and a thin film such as titanium formed by sputtering. A copper layer may be formed on the layer by sputtering.

  Next, a plating resist film 23 is pattern-formed on the upper surface of the base metal layer 7. In this case, an opening 24 is formed in the plating resist film 23 in a portion corresponding to the wiring 8 formation region. Next, by performing electrolytic plating of copper using the base metal layer 7 as a plating current path, the wiring 8 is formed on the upper surface of the base metal layer 7 in the opening 24 of the plating resist film 23. Next, the plating resist film 23 is peeled off.

  Next, as shown in FIG. 4, a plating resist film 25 is formed on the upper surface of the base metal layer 7 including the wiring 8. In this case, an opening 26 is formed in the plating resist film 25 at a portion corresponding to the connection pad portion (columnar electrode 9 formation region) of the wiring 8. Next, the metal spherical body 10 made of copper or the like is disposed on the connection pad portion upper surface of the wiring 8 in the opening 26 of the plating resist film 25. Here, the diameter of the opening 26 of the plating resist film 25 is somewhat larger than the diameter of the metal spherical body 10.

  As an example of the arrangement method of the metal spheres 10, when many metal spheres 10 are arranged on the upper surface of the plating resist film 25 and a squeegee or a brush is moved on the plating resist film 25, the opening of the plating resist film 25 is formed. The metal spherical body 10 can be disposed on the upper surface of the connection pad portion of the wiring 8 in the portion 26.

  Next, as shown in FIG. 5, the metal spherical body is formed on the upper surface of the connection pad portion of the wiring 8 in the opening 26 of the plating resist film 25 by performing electrolytic plating of copper using the base metal layer 7 as a plating current path. A plated portion 11 is formed around 10. In this case, a part of the metal spherical body 10 is projected above the plated portion 11.

  Thereby, the plated part 11 is provided around the metal spherical body 10, and a columnar electrode having a structure in which a part of the metal spherical body 10 protrudes above the plated part 11 is formed. Here, since the columnar electrode 9 has a structure in which the plated portion 11 is provided around the metal spherical body 10, the time required for the plating process may be the time for forming the plated portion 11, and the plating process time is greatly increased. It can be shortened.

  Next, when the plating resist film 25 is peeled off, and then unnecessary portions of the base metal layer 7 are removed by etching using the wiring 8 as a mask, the base metal layer 7 is formed only under the wiring 8 as shown in FIG. Remain. In this state, the columnar electrode 9 having a structure in which the plated portion 11 is provided around the metal spherical body 10 is formed on the upper surface of the connection pad portion of the wiring 8.

  Next, as shown in FIG. 7, a sealing film 11 made of an epoxy resin or the like is formed on the upper surface of the protective film 5 including the wiring 8 and the columnar electrode 9 by screen printing. In this case, the upper surface of the sealing film 12 formed on the protective film 5 is set to be somewhat higher than the upper surface of the plated portion 11. Then, the sealing film 12 is thinly formed on the surface of the metal spherical body 10 protruding from the upper surface of the plating part 11.

  Next, when the upper surface side of the sealing film 11 is etched by oxygen plasma etching until the sealing film 12 on the surface of the metal spherical body 10 and the upper surface of the plating part 11 is removed, as shown in FIG. The surface of the spherical body 10 and the upper surface of the plating part 11 are exposed, and the upper surface of the plating part 11 is substantially flush with the upper surface of the sealing film 11.

  Next, as shown in FIG. 9, solder balls 13 are formed on the upper surface of the columnar electrode 9, that is, the upper surface of the plated portion 11 including the metal spherical body 10. Next, as shown in FIG. 10, when the semiconductor wafer 21 and the like are cut along the dicing line 21, a plurality of semiconductor devices shown in FIG. 1 are obtained.

  Here, an example of a method for forming the solder ball 13 will be described. First, flux is applied to the upper surface of the columnar electrode 9, that is, the upper surface of the plated portion 11 including the metal spherical body 10. Next, the solder balls 13 are disposed and attached to the upper surface of the flux. Next, the flux is evaporated and removed by reflow, and the solder ball 13 is fixed to the upper surface of the columnar electrode 9.

  In this case, when the solder balls 13 are melted by reflow, it is not preferable that the metal spherical bodies 10 are melted simultaneously. Therefore, as the metal material of the metal spherical body 10, a metal having a melting point higher than that of the solder ball 13, such as copper (melting point 1083.4 ° C.), titanium (melting point 1660 ° C.), tungsten (melting point 340 ° C.), gold It is preferable to use a metal having a melting point of 300 ° C. or higher, such as (melting point 1064.4 ° C.).

(Second Embodiment)
FIG. 11 is a sectional view of a semiconductor device as a second embodiment of the present invention. This semiconductor device is different from the semiconductor device shown in FIG. 1 in that the columnar electrode 9 has a structure in which plated portions (not shown) are provided around a plurality of metal spherical bodies 10 in close contact with each other. . That is, the metal spherical body 10 in this case has a smaller diameter than the metal spherical body 10 shown in FIG.

  In this semiconductor device, a part of each of the plurality of metal spherical bodies 10 positioned in the uppermost layer protrudes above the plating part, and the solder ball 13 is provided on the upper surface of the plating part including these protrusions. . Therefore, also in this semiconductor device, the metal spherical body 10 protruding above the sealing film 12 bites into the solder ball 13, thereby making it difficult for cracks to occur at the interface between the columnar electrode 9 and the solder ball 13. Can do.

  The manufacturing method of this semiconductor device is almost the same as that in the first embodiment. In this case, in the process as shown in FIG. 4, a plurality of metal spherical bodies 10 are arranged in close contact with each other on the upper surface of the wiring 8 connection pad in the opening 26 of the plating resist film 25, and the process as shown in FIG. , A plurality of metal spherical bodies 10 arranged in close contact with each other are integrated by forming a plating portion around the plurality of metal spherical bodies 10.

  By the way, in the semiconductor device shown in FIG. 1, the aspect ratio (height / diameter) of the plated portion 11 is influenced by the diameter of the metal spherical body 10. That is, the diameter of the plated portion 11 cannot be made smaller than the diameter of the metal sphere 10, and the height of the plated portion 11 cannot be made larger than the diameter of the metal sphere 10. In contrast, in the semiconductor device shown in FIG. 11, the aspect ratio of the plated portion can be set regardless of the diameter of the metal spherical body 10.

(Other embodiments)
In FIG. 1 and FIG. 11, instead of the metal spherical body 10, a metal member made of a square body, a rectangular body, a pyramid body, or other shapes may be used. However, in the case shown in FIG. 11, it is necessary to form a gap for forming the plated portion between a plurality of metal members in close contact with each other. In addition, in the process as shown in FIG. 4, a metal spherical body is preferable in consideration of the arrangement method of the metal member.

1 is a cross-sectional view of a semiconductor device as a first embodiment of the present invention. Sectional drawing of what is initially prepared in the case of manufacture 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. FIG. 9 is a cross-sectional view of the process following FIG. 8. Sectional drawing of the process following FIG. 1 is a cross-sectional view of a semiconductor device as a first embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Connection pad 3 Insulating film 5 Protective film 7 Base metal layer 8 Wiring 9 Columnar electrode 10 Metal spherical body 11 Plating part 12 Sealing film 13 Solder ball

Claims (12)

  In a semiconductor device having a semiconductor substrate, a plurality of columnar electrodes provided on the semiconductor substrate, a sealing film provided around the columnar electrode on the semiconductor substrate, and a solder ball provided on the columnar electrode, The columnar electrode is composed of a metal member partially protruding above the sealing film and a plated portion provided around the metal member below the upper surface of the sealing film. A featured semiconductor device.   2. The semiconductor device according to claim 1, wherein the metal member is formed of one metal spherical body.   3. The semiconductor device according to claim 2, wherein the diameter of the columnar electrode is larger than the diameter of the metal spherical body.   2. The semiconductor device according to claim 1, wherein the metal member is composed of a plurality of metal spherical bodies in close contact with each other.   2. The semiconductor device according to claim 1, wherein the metal member is made of a metal having a melting point higher than that of the solder ball.   6. The semiconductor device according to claim 5, wherein the metal member and the plated portion are made of copper. Forming a base metal layer on the entire surface of the semiconductor substrate;
Forming a wiring on the base metal layer;
Forming a plating resist film having an opening in a portion corresponding to a connection pad portion of the wiring on the base metal layer including the wiring;
Placing a metal member on the connection pad portion of the wiring in the opening of the plating resist film;
By performing electrolytic plating using the base metal layer as a plating current path, a plating portion is disposed around the metal member on the connection pad portion of the wiring in the opening of the plating resist film, and the metal is disposed above the plating portion. Forming a part of the member so as to protrude, and forming a columnar electrode by the metal member and the plating part;
Removing the plating resist film;
Removing the base metal layer other than under the wiring;
Forming a sealing film on the semiconductor substrate including the wiring and the columnar electrode;
Etching and removing the upper surface side of the sealing film until the upper surface of the columnar electrode is exposed;
Forming a solder ball on the upper surface of the columnar electrode;
A method for manufacturing a semiconductor device, comprising:   The invention according to claim 7, wherein the step of arranging the metal member is a step of arranging one metal spherical body on the connection pad portion of the wiring in the opening of the plating resist film. A method for manufacturing a semiconductor device.   In the invention according to claim 7, the step of arranging the metal member is a step of arranging a plurality of metal spherical bodies in close contact with each other on the connection pad portion of the wiring in the opening of the plating resist film. A method of manufacturing a semiconductor device.   8. The method of manufacturing a semiconductor device according to claim 7, wherein the metal member is made of a metal having a melting point higher than that of the solder ball.   11. The method of manufacturing a semiconductor device according to claim 10, wherein the metal member and the plated portion are made of copper.   8. The method of manufacturing a semiconductor device according to claim 7, wherein etching on the upper surface side of the sealing film is oxygen plasma etching.

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