Source: http://www.google.com/patents/US7176570?dq=5787449
Timestamp: 2017-08-22 13:52:44
Document Index: 543717673

Matched Legal Cases: ['Application No. 10', 'Application No. 2002', 'art 24', 'art 24', 'art 24', 'art 24']

Patent US7176570 - Method for forming bump, semiconductor element having bumps and method of ... - Google Patents
A tip of a wire formed in the shape of a ball is bonded to an electrode by using a tool. A part of the wire is drawn from the tip bonded to the electrode. A bump is formed on the electrode by deforming a portion of the wire continuous with the tip on the tip by using the tool. The wire is cut while leaving...http://www.google.com/patents/US7176570?utm_source=gb-gplus-sharePatent US7176570 - Method for forming bump, semiconductor element having bumps and method of manufacturing the same, semiconductor device and method of manufacturing the same, circuit board, and electronic equipment
Publication number US7176570 B2
Application number US 11/191,976
Also published as CN1267978C, CN1440062A, US6946380, US20030166333, US20050258214
Publication number 11191976, 191976, US 7176570 B2, US 7176570B2, US-B2-7176570, US7176570 B2, US7176570B2
Inventors Takuya Takahashi
Patent Citations (22), Referenced by (7), Classifications (72), Legal Events (2)
US 7176570 B2
A tip of a wire formed in the shape of a ball is bonded to an electrode by using a tool. A part of the wire is drawn from the tip bonded to the electrode. A bump is formed on the electrode by deforming a portion of the wire continuous with the tip on the tip by using the tool. The wire is cut while leaving the bump on the electrode.
1. A semiconductor element having bumps comprising:
a semiconductor element which includes an integrated circuit and electrodes; and
bumps provided on the electrodes, respectively, each of the bumps being used for connecting with a wire and including a bottom end connected with each of the electrodes and a top end having an almost smooth surface,
wherein the top end of each of the bumps is formed so that a width of the top end elongated in a drawing direction of the wire, and a height of the top end decreases as a distance from the wire increases along the drawing direction of the wire.
2. The semiconductor element having bumps as defined by claim 1,
wherein the semiconductor element is a semiconductor wafer including a plurality of the integrated circuits.
3. The semiconductor element having bumps as defined by claim 1,
4. A semiconductor element having bumps comprising:
a semiconductor wafer which includes a plurality of integrated circuits and electrodes formed on an edge portion of a region including each of the integrated circuits; and
bumps provided on the electrodes, respectively, each of the bumps having a bottom end connected with each of the electrodes and a top end having an almost smooth surface,
wherein the top end of each of the bumps is formed so that a width of the top end is elongated in a direction from the edge portion to a center portion of the region, and a height of the top end decreases along the direction from the edge portion to the center portion of the region.
5. A semiconductor element having bumps comprising:
a semiconductor chip which includes an integrated circuit and electrodes formed on an edge portion of the semiconductor chip; and
wherein the top end of each of the bumps is formed so that a width of the top end is elongated in a direction from the edge portion to a center portion of the semiconductor chip, and a height of the top end decreases along the direction from the edge portion to the center portion of the semiconductor chip.
6. A semiconductor device comprising the semiconductor element having bumps as defined by claim 1, and a lead which is electrically connected with each of the bumps through the wire.
7. A semiconductor device comprising the semiconductor element having bumps as defined by claim 5, and a lead which is electrically connected with each of the bumps through a wire.
8. The semiconductor device as defined by claim 6,
wherein one end of the wire formed in a shape of a ball is joined to the lead, and
wherein the other end of the wire is joined to each of the bumps.
9. The semiconductor device as defined by claim 7,
This is a Division of Application No. 10/347,474 filed Jan. 21, 2003 now U.S. Pat. No. 6,946,380. The entire disclosure of the prior application is hereby incorporated by reference herein in its entirety.
Japanese Patent Application No. 2002-41678 filed on Feb. 19, 2002, is hereby incorporated by reference in its entirety.
The present invention relates to a method for forming a bump, a semiconductor element having bumps and a method of manufacturing the same, a semiconductor device and a method of manufacturing the same, a circuit board, and electronic equipment.
In the manufacture of semiconductor devices, a method in which a bump is formed on an electrode by applying wire bonding technology is known. According to this method, a tip of a wire is formed in the shape of a ball and the wire is cut while allowing the tip to remain on the electrode. In a conventional method, since a part of the wire in the shape of a projection remains on the bump, it is difficult to bond another wire to the bump.
A method for forming a bump according to one aspect of the present invention includes steps of:
(a) bonding a tip of a wire formed in a shape of a ball to an electrode by using a tool;
(b) drawing a part of the wire from the tip bonded to the electrode;
(c) deforming the wire at a portion continuous with the tip, on the tip by using the tool; and
(d) cutting the wire while leaving the tip and the deformed portion of the wire on the electrode.
A method of manufacturing a semiconductor element according to another aspect of the present invention includes steps of:
(a) bonding a tip of a wire formed in a shape of a ball to an electrode of a semiconductor element by using a tool, the semiconductor element having an integrated circuit;
(c) forming each of the bumps on the electrode by deforming the wire at a portion continuous with the tip, on the tip by using the tool; and
(d) cutting the wire while leaving each of the bumps on the electrode.
A method of manufacturing a semiconductor device according to a further aspect of the present invention includes the above method of manufacturing a semiconductor element having bumps,
wherein the method further comprises a wire bonding step for electrically connecting each of the bumps with a lead.
A semiconductor element having bumps according to a still further aspect of the present invention is manufactured by using the above method.
A semiconductor element having bumps according to a still further aspect of the present invention includes:
A semiconductor device according to a still further aspect of the present invention is manufactured by using the above method.
A semiconductor device according an even further aspect of to the present invention includes the above semiconductor element having bumps, and a lead which is electrically connected with each of the bumps through the wire.
A circuit board according to a yet further aspect of the present invention has the above semiconductor device mounted on the circuit board.
Electronic equipment according to an even more further aspect of the present invention includes the above semiconductor device.
FIGS. 1A to 1C illustrate a method for forming a bump and a method of manufacturing a semiconductor element having bumps according to a first embodiment of the present invention;
FIG. 4 is a cross-sectional view along the line VI—VI shown in FIG. 3;
FIG. 8 is a cross-sectional view along the line VIII—VIII shown in FIG. 7;
An embodiment of the present invention may facilitate formation of a bump which is easily wire bonded.
(1) A method for forming a bump according to an embodiment of the present invention includes steps of:
According to this embodiment of the present invention, a bump having an almost smooth surface can be easily formed on the electrode. Specifically, since the bump is formed on the electrode and the surface of the bump is smoothed by using the tool used for bonding, the manufacturing steps are simple and quick.
(2) In this method for forming a bump, a part of the wire may be drawn by bending the part of the wire in the step (b).
This enables the portion of the wire continuous with the tip to be easily deformed on the tip.
(3) In this method for forming a bump, the wire may be drawn above the electrode by moving the tool in a height direction of the tip, and a part of the wire may be bent by moving the tool in a width direction of the tip, in the step (b).
(4) In this method for forming a bump, the tool may be moved above the tip in a width direction of the tip while the portion of the wire continuous with the tip being pressed and deformed by the tool in the step (c), and
the wire may be cut by thinly stretching the wire in the step (d).
According to this method, the tool is moved in the width direction of the tip of the wire when applying pressure. This enables the bump to be formed in an optimum shape. Moreover, since the wire can be cut, the manufacturing steps can be facilitated.
(5) In this method for forming a bump, a part of the wire left on the electrode may be formed to have a bottom end connected with the electrode and a top end having an almost smooth surface in the step (c).
(6) In this method for forming a bump, the top end may be formed so that a width of the top end is elongated in a moving direction of the tool in the step (c).
This enables another wire to be easily bonded to the top end of the bump, for example.
(7) In this method for forming a bump, the top end may be formed so that a height of the top end decreases along a moving direction of the tool in the step (c).
(8) In this method for forming a bump, the step (c) and the step (d) may be performed while applying ultrasonic vibration to the tip.
This enables continuous processing capability of the wire to be stabilized.
(9) In this method for forming a bump, the tool may have a hole into which the wire is inserted, and the portion of the wire continuous with the tip may be deformed by an open end of the tool in the step (c).
(10) A method of manufacturing a semiconductor element according to another embodiment of the present invention includes steps of:
(11) In this method of manufacturing a semiconductor element, a part of the wire may be drawn by bending the part of the wire in the step (b).
(12) In this method of manufacturing a semiconductor element, the wire may be drawn above the electrode by moving the tool in a height direction of the tip, and a part of the wire is bent by moving the tool in a width direction of the tip, in the step (b).
(13) In this method of manufacturing a semiconductor element,
the tool may be moved above the tip in a width direction of the tip while the portion of the wire continuous with the tip being pressed and deformed by the tool in the step (c), and
(14) In this method of manufacturing a semiconductor element, the tool may be moved on the tip in a direction in which the wire connected with each of the bumps is drawn toward each of the bumps, in the step (c).
This enables the width of the top end of the bump to be elongated in the drawing direction of the wire, or the height of the top end of the bump to be decreased along the drawing direction of the wire, for example.
(15) In this method of manufacturing a semiconductor element,
the semiconductor element may be a semiconductor wafer including a plurality of the integrated circuits,
the electrode may be formed on an edge portion of a region including each of the integrated circuits, and
the tool may be moved on the tip from the edge portion toward a center of the region in the step (c).
This enables the width of the top end of the bump to be elongated in the direction from the edge portion to the center portion of the region of the semiconductor wafer, or the height of the top end of the bump to be decreased along the direction from the edge portion to the center portion of the region of the semiconductor wafer, for example.
(16) In this method of manufacturing a semiconductor element,
the semiconductor element may be a semiconductor chip,
the electrode may be formed on an edge portion of the semiconductor chip, and
the tool may be moved on the tip from the edge portion toward a center portion of the semiconductor chip in the step (c).
This enables the width of the top end of the bump to be elongated in the direction from the edge portion to the center portion of the semiconductor chip, or the height of the top end of the bump to be decreased along the direction from the edge portion to the center portion of the semiconductor chip, for example.
(17) In this method of manufacturing a semiconductor element, each of the bumps may be formed to have a bottom end connected with the electrode and a top end having an almost smooth surface in the step (c).
(18) In this method of manufacturing a semiconductor element, the top end of each of the bumps may be formed so that a width of the top end is elongated in a moving direction of the tool in the step (c).
(19) In this method of manufacturing a semiconductor element, the top end of each of the bumps may be formed so that a height of the top end decreases along a moving direction of the tool in the step (c).
(20) In this method of manufacturing a semiconductor element, the step (c) and the step (d) may be performed while applying ultrasonic vibration to the tip.
(21) In this method of manufacturing a semiconductor element, the tool may have a hole into which the wire is inserted, and
the portion of the wire continuous with the tip may be deformed by an open end of the tool in the step (c).
(22) In this method of manufacturing a semiconductor element, the semiconductor element may have a plurality of the electrodes, and
the bumps may be formed on the electrodes, respectively, by repeating the steps (a) to (d).
(23) A method of manufacturing a semiconductor device according to a further embodiment of the present invention includes the above method of manufacturing a semiconductor element having bumps, wherein the method further comprises a wire bonding step for electrically connecting each of the bumps with a lead.
(24) In this method of manufacturing a semiconductor device, in the wire bonding step, a tip of a second wire may be formed in a shape of a ball, the tip of the second wire may be bonded to the lead, the second wire may be drawn from the lead to each of the bumps, and a part of the second wire may be bonded to each of the bumps.
(25) A semiconductor element having bumps according to a still further embodiment of the present invention is manufactured by the above method.
(26) A semiconductor element having bumps according to a still further embodiment of the present invention includes:
According to this embodiment of the present invention, the width of the top end of the bump is elongated in the drawing direction of the wire toward the bump, and the height of the top end of the bump decreases along the drawing direction of the wire toward the bump. This enables another wire to be easily bonded to the top end of the bump, for example.
(27) In this semiconductor element having bumps, the semiconductor element may be a semiconductor wafer including a plurality of the integrated circuits.
(28) In this semiconductor element having bumps, the semiconductor element may be a semiconductor chip.
(29) A semiconductor element having bumps according to a still further embodiment of the present invention includes:
According to this embodiment of the present invention, the width of the top end of the bump is elongated in the direction from the edge portion to the center portion of the region including the integrated circuit, and the height of the top end of the bump decreases along the direction from the edge portion to the center portion of the region including the integrated circuit. This enables another wire to be easily bonded to the top end of the bump, for example.
(30) A semiconductor element having bumps according to a still further embodiment of the present invention includes:
According to this embodiment of the present invention, the width of the top end of the bump is elongated in the direction from the edge portion to the center portion of the semiconductor chip, and the height of the top end of the bump decreases along the direction from the edge portion to the center portion of the semiconductor chip. This enables another wire to be easily bonded to the top end of the bump, for example.
(31) A semiconductor device according to a still further embodiment of the present invention is manufactured by the above method.
(32) A semiconductor device according to an even further embodiment of the present invention includes the above semiconductor chip having bumps, a lead which is electrically connected with each of the bumps through the wire.
(33) In this semiconductor device, one end of the wire formed in a shape of a ball may be joined to the lead, and the other end of the wire may be joined to each of the bumps.
(34) A circuit board according to a yet further embodiment of the present invention has the above semiconductor device mounted on the circuit board.
(35) Electronic equipment according to an even more further embodiment of the present invention includes the above semiconductor device.
FIGS. 1A to 1C, FIGS. 2A and 2B, and FIGS. 3 to 8 illustrate a semiconductor element having bumps and a method of manufacturing the same according to the present embodiment. In the present embodiment, a bump 40 is formed on an electrode 12 of a semiconductor element 10. The bump 40 is formed by bonding a wire 20 to the electrode 12 by using a tool 30. The bump 40 is used as a terminal for wire bonding.
The wire 20 is held by a clamper 36. The clamper 36 is disposed above the tool 30, specifically, on the side opposite to the electrode 12. The wire 20 can be held by closing the clamper 36. The wire 20 can be handled by the tool 30 by opening the clamper 36. In the example shown in FIG. 1A, the tool 30 and the clamper 36 are formed separately. However, the tool 30 and the clamper 36 may be formed integrally. For example, the tool 30 may have a function of the clamper 36.
A tip 22 of the wire 20 projects outside the opening of the hole 32 on the side of the electrode 12. An open end (or pressing section) 34 of the hole 32 is capable of pressing a part of the wire 20 (see FIGS. 1B, 2A, and 2B). A part (near the periphery of the tool) of the open end 34 may be sloped, as shown in the FIG. 1A. The open end 34 may be a smooth surface.
As shown in FIG. 1B, the tip 22 of the wire 20 is disposed above one of the electrodes 12. The tool 30 is brought down in a state in which the clamper 36 is opened. The tip 22 of the wire 20 is bonded to the electrode 12 in this manner. In more detail, the tip 22 of the wire 20 is pressed by the open end 34 of the tool 30. It is preferable to apply ultrasonic vibration, heat, or the like while pressing the tip 22. This enables the tip 22 to be joined to the electrode 12 in a good state. A top end and a bottom end larger (wider) than the top end are formed at the tip 22 of the wire 20 by the pressure applied by the open end 34.
In the example shown in FIG. 1C, the part 24 of the wire 20 is drawn from the tip 22 so that the part 24 is bent. This enables the wire 20 to be easily deformed at a portion continuous with the tip 22, on the tip 22. For example, the part 24 of the wire 20 may be bent by drawing the wire 20 above the electrode 12 by moving the tool 30 in a height direction of the tip 22, and then moving the tool 30 in a width direction of the tip 22. The form (shape, method, for example) of bending the part 24 of the wire 20 is not limited to the above-described example.
In the example shown in FIG. 2A, the tool 30 is moved on the tip 22 in the width direction of the tip 22 (direction indicated by an arrow shown in FIG. 2A) while applying pressure to the tip 22. In other words, the tool 30 is slid in the direction parallel to the surface of the semiconductor element 10 while applying pressure to the tip 22. The bump 40 is formed in an optimum shape in this manner, as shown in FIGS. 3 and 4. FIG. 3 is a plan view of the semiconductor element after formation of the bump. FIG. 4 is a cross-sectional view along the line VI—VI shown in FIG. 3.
FIGS. 7 and 8 illustrate the moving direction of the tool 30 (direction of the width of the tip 22). In more detail, FIG. 7 is a plan view of the semiconductor chip after formation of the bump. FIG. 8 is a cross-sectional view along the line VIII—VIII shown in FIG. 7. Each direction indicated by an arrow shown in FIG. 7 indicates a drawing direction of the wire 120 to be connected in a subsequent step toward the bump 40. The wire 120 electrically connects the electrode 12 of the semiconductor chip 16 with another electronic component (interconnect of a substrate or another semiconductor chip, for example).
As shown in FIG. 9, a tool 130 which supports the wire 120 is provided. A tip 122 of the wire 120 is formed in the shape of a ball and bonded to the electrode 52 by using the tool 130. The wire 120, the tool 130, and the clamper 136 may be the same as described above. The tool 130 has a hole 132 and an open end 134. The method of forming the tip 122 of the wire 120 in the shape of a ball is the same as described above.
According to the method of manufacturing a semiconductor device of the present embodiment, a part of the wire 120 is bonded to the center of the bump 40 or a part of the bump 40 beyond the center in the drawing direction of the wire 120. This enables a part of the wire 120 which projects from the bump 40 toward the electrode 52 in the drawing direction of the wire 120 to be prevented from being pressed by the tool 130, for example. This prevents the wire 120 from sagging. Therefore, the wire 120 can be bonded to the bump 40 in a reliable and stable state.
FIGS. 15A to 20 are views showing a semiconductor device and a method of manufacturing the same according to the present embodiment. In the present embodiment, first bonding of another wire 220 to the bump 40 to which the wire 120 is bonded is performed.
As shown in FIG. 15A, a tool 230 which supports the wire 220 is provided. The tip 222 of the wire 220 is formed in the shape of a ball. The wire 220, the tool 230, and a clamper 236 may be the same as described above. The tool 230 has a hole 232 and an open end 234. The method of forming the tip 222 of the wire 220 in the shape of a ball is also the same as described above.
The tip 222 of the wire 220 and the tool 230 may be prevented from coming in contact with a part of the wire 120 which is less deformed than a point Z shown in FIG. 18 (on the left side of the point Z). The point Z shown in FIG. 18 is a boundary point at which the diameter (thickness) of the wire 120 decreases to almost one third the original diameter. This enables the above effects to be achieved still more reliably.
A plurality of semiconductor chips 16, 116, and 316 are placed on one side of the die pad 72. The other side of the die pad 72 is exposed from the sealing section 70. This enables radiation properties of the semiconductor device to be improved. The sealing section 70 is generally formed of an epoxy resin. Each of the leads 74 includes an inner lead 76 electrically connected with one of the semiconductor chips (semiconductor chip 116 in FIG. 20) inside the sealing section 70, and an outer lead 78 which projects outside the sealing section 70. The outer lead 78 is bent in a specific shape (gull-wing shape in FIG. 20), and becomes an external terminal of the semiconductor device. As shown in FIG. 20, a metal film (plated film, for example) such as a brazing material is provided to the outer leads 78. The semiconductor chips 16, 116, and 316 are electrically connected with one another through the wires 120 and 220. The connection structure through the wires is the same as described above.
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JP2000323515A Title not available
JPH0314235A Title not available
JPH01293626A Title not available
JPH02250328A Title not available
JPH03183139A Title not available
JPH03233946A Title not available
JPH04123434A Title not available
JPH05275428A Title not available
JPH05326601A Title not available
JPH10512399A Title not available
JPS63173345A Title not available
WO1997012394A1 Sep 19, 1996 Apr 3, 1997 Siemens Aktiengesellschaft Method of electrically connecting a semiconductor chip to at least one contact surface
U.S. Classification 257/737, 257/784, 257/E23.021, 257/E21.508, 257/E23.052, 257/E21.518, 257/780, 257/786
International Classification H01L23/485, H01L23/495, H01L23/48, H01L21/60, H01L21/607
Cooperative Classification H01L2924/181, H01L2924/15787, H01L2224/45015, H01L2924/01005, H01L23/49575, H01L2924/01013, H01L2224/0401, H01L2924/14, H01L2924/01079, H01L2224/4911, H01L24/03, H01L2224/85186, H01L24/48, H01L2924/014, H01L2224/48471, H01L2224/85205, H01L2224/78301, H01L2924/01059, H01L2224/48091, H01L2224/48247, H01L2924/01004, H01L24/78, H01L2224/48479, H01L2224/85986, H01L2224/45144, H01L2924/01039, H01L24/45, H01L2924/09701, H01L2224/48499, H01L2924/01006, H01L24/11, H01L2924/15311, H01L2224/48647, H01L2924/0105, H01L2924/01029, H01L24/49, H01L2224/04042, H01L2224/85051, H01L2224/49171, H01L2224/49429, H01L2224/13099, H01L2224/48624, H01L2924/01078, H01L24/05, H01L2224/05647, H01L2224/05624, H01L24/85, H01L2224/32145, H01L2224/48145, H01L2224/73265, H01L2224/16245
European Classification H01L24/48, H01L24/11, H01L24/85, H01L24/49, H01L24/05, H01L24/03, H01L24/78, H01L23/495L