JP2012199358A - Chip heating head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip heating head capable of mounting a chip on a substrate without junction failure, by suppressing the lowering of the temperature of a heated chip to minimize temperature variation.SOLUTION: A chip heating heater portion 5 is composed of a heater body 10 functioning as a heat source for heating a chip 7; and a collet 11 which is heated by the heater body 10 and grips the chip 7 by vacuum suction and the like. In a heat transmission direction from the heater body 10 to the chip 7, the contact density of the collet 11 and the chip 7 is different in a center part and an outer peripheral part of the chip 7. Concretely, a contacting portion in which the collet 11 contacts with the chip 7 is provided at the center part of the chip 7, and a non-contacting portion in which the collet 11 does not contact with the chip is provided at the outer peripheral portion of the chip 7. Therefore, a temperature distribution of the chip 7 is made to be uniform, and the chip 7 can be mounted on a substrate without causing junction failures such as non-fusion of solder or void remaining.

Description

  The present invention relates to a chip heating head used in a semiconductor chip bonding apparatus for mounting a semiconductor chip (hereinafter sometimes simply referred to as a chip) on a substrate, and more particularly to a chip such as a flip chip mounting region on a substrate. The present invention relates to a chip heating head used in a semiconductor chip bonding apparatus that bonds chips by heating in a mounting region.

  Conventionally, as a bonding method between a chip and a substrate or between a chip and a chip, a method of bonding both using a solder material, Au bump, or the like is generally performed. In these bonding methods, the bonding parts are brought into contact with each other with the solder material or Au bumps attached to the chip-to-substrate or chip-to-chip bonding parts, and the solder material or Au bumps are melted and solidified for wiring. Are connected. At this time, the chip and substrate wiring parts are joined while melting the solder material and Au bumps by uniformly pressing and heating the chip and substrate using a heat source such as a chip heating head (for example, patents) Reference 1).

  In general, since a method of heating the chip side by a chip heating head is performed, the chip needs to be heated by a chip heating head having a desired heat capacity or a single heater in consideration of the size of the chip. There is. In addition, from the viewpoint of preventing chip deterioration and shortening the mounting process time, in order to shorten the chip mounting processing time, it is necessary to quickly heat and cool the chip. A heater having such a small heat capacity and high thermal response is used.

  On the other hand, since the heating temperature of the chip or the substrate varies depending on the region, there may be variations in the molten state of the solder material or Au bump in the chip. In particular, heaters with high thermal response, such as ceramic heaters, have a small heat capacity, so they tend to cause a temperature drop due to disturbance, and the thermal diffusivity is also small compared to metals, so the uniformity of heat distribution is poor, so the heating temperature is low. Variation is likely to occur. For example, in a chip having a large outer dimension such as a FCBGA (Flipchip Ball Grid Array), the distribution temperature decreases from the center of the chip toward the outer periphery of the chip. At the outer periphery, the solder material and Au bumps are in an unmelted state, which causes a bonding failure.

  Therefore, in order to solve the problem of such variation in temperature distribution, the heating temperature of a heating source such as a chip heating head is increased, or the heating time is extended so that the outer peripheral portion of the chip is sufficiently heated. The method to be taken is taken. However, since gas is generated from the inside of the solder material or Au bump by heating, there is a possibility that it remains as an unjoined portion inside the solder material or Au bump. Moreover, since it becomes easy to generate | occur | produce gas by making it the state of a high temperature heating or hold | maintaining a heating state, it is unpreferable to raise heating temperature or lengthen heating time. There is also a method of providing a plurality of heaters as heating sources and heating the outer peripheral part of the chip at a temperature higher than the central part of the chip. However, since a plurality of heaters are required, the cost increases and heating for a small chip is possible. It becomes difficult to respond.

  Therefore, in order to eliminate the above problems, by forming concave portions at equal intervals in the peripheral portion of the substrate mounting member and the contact portion of the support member, the temperature distribution of the substrate mounting portion is made uniform. A technique for improving a film forming process on a substrate is disclosed (for example, see Patent Document 2).

  In addition, as a related technique, a substrate deformation prevention portion having a recess formed in the center portion of the substrate contact surface of the bonding tool is provided so that the substrate is not deformed when the semiconductor chip (chip) is bonded to the substrate. Has been disclosed (see Patent Document 3). According to this technique, when a chip having bump electrodes arranged along the outer periphery is bonded to a substrate, a recess formed in the central portion of the substrate contact surface of the bonding tool causes the bump electrode of the semiconductor chip to be located inside. Since the pressing force of the bonding tool is not applied, the deformation of the substrate can be prevented.

  As another related technique, a technique for stably mounting a semiconductor chip on a substrate while avoiding damage to the semiconductor chip due to a difference in thermal expansion coefficient between the semiconductor chip and the mounting substrate is disclosed (see Patent Document 4). ). According to this technique, by providing a recess on the stage side on which the semiconductor chip is placed, the mounting substrate is curved toward the recess when the semiconductor chip is pressed toward the mounting substrate by a pressure / heating head. By bonding the semiconductor chip to the substrate in the state, the recess absorbs the difference in thermal expansion coefficient between the semiconductor chip and the mounting substrate, so that the semiconductor chip can be stably mounted on the substrate.

JP 2005-142460 A JP 2004-193471 A JP 2006-310354 A JP 2007-214291 A

  However, in the method of making the substrate temperature uniform as in the technique disclosed in Patent Document 2, the heater component that becomes a heating source becomes larger than the substrate, so that the chip is mounted on the substrate at a narrow pitch. From the viewpoint of structure, it is difficult to apply as a semiconductor chip bonding apparatus that performs fine processing.

  In addition, the technique disclosed in Patent Document 3 can prevent a substrate from being deformed by providing a substrate deformation preventing portion having a recess, and can properly mount a chip on the substrate. The publication does not disclose a technique for making the temperature distribution of the chip uniform. That is, in the bonding tool, even if a recess is provided in the inner part of the bump electrode on the outer periphery of the chip, the correspondence between the size of the chip and the size of the recess is unspecified, so the technology for uniformizing the temperature distribution of the chip Can not be deployed.

  Furthermore, the technique disclosed in Patent Document 4 absorbs a difference in thermal expansion coefficient between the semiconductor chip and the substrate by providing a recess in the central portion on the stage side on which the semiconductor chip is placed, so that the semiconductor chip is mounted on the substrate. Although it can be mounted stably, since the heat of the heater is transferred to the semiconductor chip without passing through the stage side, the temperature distribution of the semiconductor chip cannot be made uniform by the recess of the stage.

  The present invention has been made in view of the above-described circumstances, and mounts a chip on a substrate without defective bonding by suppressing temperature drop of a heated chip and minimizing temperature variation of the chip. An object of the present invention is to provide a chip heating head that can be used.

  In order to achieve the above object, a chip heating head according to the present invention is a chip heating head comprising heating means for heating a semiconductor chip and a collet for adsorbing or gripping the semiconductor chip. The contact density with the semiconductor chip is roughly distributed so that the heat transfer capacity transferred from the heating means to the semiconductor chip is distributed.

  According to another aspect of the present invention, there is provided a chip heating head comprising: a heating means for heating a semiconductor chip; and a collet for adsorbing or holding the semiconductor chip. A feature is that the heat transfer capacity to the semiconductor chip is distributed by gradually increasing the contact density with the semiconductor chip toward the center of the chip.

  Moreover, the chip heating head according to the present invention is a chip heating head comprising heating means for heating a semiconductor chip and a collet for adsorbing or holding the semiconductor chip, and the collet has a hollow portion inside itself. Thus, the heat transfer capacity to the semiconductor chip is distributed.

  According to the chip heating head of the present invention, it is possible to increase the amount of heat transfer to the outer peripheral portion of the semiconductor chip that is likely to decrease in temperature due to large contact with the atmosphere. It can be minimized. As a result, the semiconductor chip can be mounted on the substrate without causing a bonding failure between the semiconductor chip and the substrate due to unmelted solder, residual voids, or the like. As a result, it is possible to reduce the yield when the semiconductor chip is mounted on the substrate.

It is a perspective view which shows the structure of the semiconductor chip mounting joining apparatus which concerns on one Embodiment of this invention. FIG. 2 is an exploded view of a chip heater unit (chip heating head) and its peripheral structure shown in FIG. 1. It is detail drawing of the chip | tip heater part which concerns on 1st Embodiment of this invention, (a) is a longitudinal cross-sectional view, (b) is a figure of the contact part of a collet and a chip | tip. It is a longitudinal cross-sectional view of the chip | tip heater part which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the chip | tip heater part which concerns on 3rd Embodiment of this invention. It is detail drawing of the chip | tip heater part which concerns on 4th Embodiment of this invention, (a) is a longitudinal cross-sectional view, (b) is a figure of the contact part of a collet and a chip | tip. It is a longitudinal cross-sectional view of the chip | tip heater part which concerns on 5th Embodiment of this invention. It is a longitudinal cross-sectional view of the chip | tip heater part which concerns on 6th Embodiment of this invention.

  A chip heating head (heater heater unit) according to an embodiment of the present invention is a chip heating head used in a semiconductor chip bonding apparatus that bonds semiconductor chips by heating, and a heat transfer direction of a heating means (heater body). 1 is characterized in that the contact density is different between the center portion of the semiconductor chip and the outer peripheral portion of the chip.

  Preferably, the contact density is configured to differ stepwise between the chip center and the chip outer periphery. The chip heating head includes a heating unit (heater body) serving as a heat source for heating the semiconductor chip, and a collet that is heated by the heating unit and holds the semiconductor chip. Hereinafter, several preferred embodiments of the chip heating head according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view showing a configuration of a semiconductor chip mounting bonding apparatus according to an embodiment of the present invention. As shown in FIG. 1, a substrate 1 on which a chip (not shown) is mounted is held by a substrate stage 2, and the substrate stage 2 is driven horizontally in the X and Y directions by an X axis stage 3 and a Y axis stage 4. be able to. The chip is held by a chip heater unit (chip heating head) 5, and the chip heater unit 5 can be driven in the vertical direction by the Z-axis stage 6.

  FIG. 2 is an exploded view of the chip heater unit (chip heating head) 5 and its peripheral structure shown in FIG. As shown in FIG. 2, the chip heater 5 placed on the lower part of the Z-axis stage 6 includes a heater 10 and a collet 11 for holding the chip 7. The collet 11 can attract the chip 7 by being connected to a vacuum generator (not shown), and can hold the chip 7 by a clamp mechanism (not shown).

  3A and 3B are detailed views of the chip heater 5 according to the first embodiment of the present invention. FIG. 3A is a longitudinal sectional view, and FIG. 3B is a diagram of a contact portion between the collet 11 and the chip 7. As shown in FIGS. 3A and 3B, the chip heater unit (chip heating head) 5 is heated by the heater body 10 serving as a heat source for heating the chip 7, and vacuum suction or the like. And a collet 11 that holds the chip 7. The collet 11 has a shape such that only the outer periphery of the chip 7 contacts. Therefore, the amount of heat transfer to the outer periphery of the chip where the temperature is likely to decrease when exposed to the outside air can be made larger than that at the center of the chip. Thereby, the temperature distribution of the chip 7 can be made substantially uniform.

(Second Embodiment)
FIG. 4 is a longitudinal sectional view of the chip heater 5 according to the second embodiment of the present invention. As shown in FIG. 4, the chip heater unit 5 includes a heater body 10 serving as a heat source for heating the chip 7, and a collet 11 that is heated by the heater body 10 and holds the chip 7 by vacuum suction or the like. ing. Further, the collet 11 is shaped so as to come into contact with the outer periphery of the chip 7 and the center of the chip. For example, when the chip 7 has a size larger than that of the first embodiment shown in FIG. 3 and the temperature in the center of the chip is too low, as shown in FIG. By bringing the collet 11 into contact with the part, heat transfer to the center part of the chip can be assisted. Thereby, even if the chip 7 has a relatively large size, the temperature distribution of the chip 7 can be made substantially uniform.

(Third embodiment)
FIG. 5 is a longitudinal sectional view of the chip heater 5 according to the third embodiment of the present invention. As shown in FIG. 5, the chip heater unit 5 includes a heater main body 10 that is a heat source for heating the chip 7 and a collet 11 that is heated by the heater main body 10 and holds the chip 7 by vacuum suction or the like. ing. In addition, the collet 11 has a dense contact surface with the chip outer periphery of the chip 7 and a rough contact surface with the chip center. As a result, when the chip 7 is warped, the contact density of the chip central portion can be reduced by increasing the surface roughness of the contact surface to the chip central portion. Therefore, even when the chip 7 is warped, the temperature distribution of the chip 7 can be made substantially uniform.

(Fourth embodiment)
6A and 6B are detailed views of a chip heater according to the fourth embodiment of the present invention, in which FIG. 6A is a longitudinal sectional view, and FIG. 6B is a diagram of a contact portion between a collet and a chip. As shown in FIG. 6, the chip heater unit 5 includes a heater body 10 serving as a heat source for heating the chip 7, and a collet 11 that is heated by the heater body 10 and holds the chip 7 by vacuum suction or the like. ing. Further, the collet 11 is shaped so as to come into contact with the four corners of the outer peripheral portion of the chip 7. Accordingly, when the chip 7 is smaller in size than the case of the first embodiment shown in FIG. 3 and the temperature decrease at the outer periphery of the chip is small, but the temperature decrease at the four corners of the chip is large, only the four corners of the chip 7 are obtained. By contacting with the collet 11, the temperature distribution of the chip 7 can be made substantially uniform.

(Fifth embodiment)
FIG. 7 is a longitudinal sectional view of a chip heater 5 according to the fifth embodiment of the present invention. As shown in FIG. 7, the chip heater unit 5 includes a heater body 10 serving as a heat source for heating the chip 7, and a collet 11 that is heated by the heater body 10 and holds the chip 7 by vacuum suction or the like. ing. The collet 11 is provided with a non-contact surface at the center of the heater 10 and is in contact with the outer periphery of the heater 10. As a result, even if the contact surface between the collet 11 and the chip 7 is made uniform, the collet 11 and the central part of the heater 7 are non-contact surfaces. As a result, the temperature distribution of the chip 7 can be made substantially uniform.

(Sixth embodiment)
FIG. 8 is a longitudinal sectional view of the chip heater 5 according to the sixth embodiment of the present invention. As shown in FIG. 7, the chip heater unit 5 includes a heater body 10 serving as a heat source for heating the chip 7, and a collet 11 that is heated by the heater body 10 and holds the chip 7 by vacuum suction or the like. ing. The collet 11 has a configuration in which a cavity is provided inside the collet near the center. As a result, even if the contact surface between the collet 11 and the chip 7 is made uniform, a cavity is provided in the collet near the center of the collet 11, so that the heat conduction at the chip outer periphery of the chip 7 is improved. Therefore, the temperature distribution of the chip 7 can be made substantially uniform.

  As described above, according to the chip heater unit (chip heating head) used in the semiconductor chip bonding apparatus according to the embodiment, the chip heater unit 5 is in contact with the collet 11 that holds the chip 7. Heating is performed to bond the chip 7 to a substrate (not shown). The collet 11 is in contact with the chip 7 in order to hold the chip 7. Therefore, the heat from the chip heater 5 is efficiently transferred to the chip 7 via the collet 11.

  Further, the shape of the collet 11 that determines the heat transfer direction for conducting the heat from the chip heater 5 to the chip 7 is different in the contact density between the chip 7 and the chip outer periphery. That is, the contact density between the chip 7 and the collet 11 is small at the center of the chip, and the contact density between the chip 7 and the collet 11 is large at the outer periphery of the chip.

  As a result, due to the heat transfer from the chip heater unit 5, the chip outer periphery of the chip 7 is heated so that the temperature is higher than the center of the chip. In other words, because the contact area with the atmosphere is large, the amount of heat transfer to the outer periphery of the chip where temperature drop is likely to occur can be increased, so that variations in temperature distribution within the chip 7 can be minimized. Become.

  As described above, the embodiments of the chip heating head (chip heater unit) according to the present invention have been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to these embodiments. Even if there is a design change or the like within a range not departing from the gist of the invention, it is included in the present invention. For example, the collet has a distribution in the heat transfer capacity transferred from the heater body to the chip by gradually increasing the contact density with the chip from the vicinity of the outer periphery to the vicinity of the center. It may be configured. Moreover, the temperature variation of the chip may be minimized by heating the chip with a plurality of heaters.

1 Substrate 2 Substrate stage 3 X-axis stage 4 Y-axis stage 5 Chip heater (chip heating head)
6 Z-axis stage 7 Chip 10 Heater body (heating means)
11 Collet

Claims (6)

In a chip heating head comprising heating means for heating a semiconductor chip, and a collet that sucks or grips the semiconductor chip,
The chip heating head according to claim 1, wherein the collet distributes a contact density with the semiconductor chip in a coarse and dense manner so that a heat transfer capacity transferred from the heating means to the semiconductor chip is distributed.   The collet is distributed in the heat transfer capacity transferred from the heating means to the semiconductor chip by gradually increasing the contact density with the semiconductor chip from the vicinity of the outer periphery of the semiconductor chip to the vicinity of the center. The chip heating head according to claim 1, wherein the chip heating head is provided.   The collet has a contact portion that contacts the semiconductor chip and a non-contact portion that does not contact the semiconductor chip on a surface facing the semiconductor chip, so that the contact density with the semiconductor chip is roughly distributed. The chip heating head according to claim 1, wherein the chip heating head is provided.   4. The chip heating head according to claim 3, wherein the collet is provided with the non-contact portion near a central portion of the semiconductor chip and the contact portion near an outer peripheral portion of the semiconductor chip. In a chip heating head comprising heating means for heating a semiconductor chip and a collet for adsorbing or holding the semiconductor chip,
The collet has a distribution of heat transfer capacity to the semiconductor chip by gradually increasing the contact density with the semiconductor chip from the outer periphery of the heating means toward the chip center of the semiconductor chip. A chip heating head characterized by that. In a chip heating head comprising heating means for heating a semiconductor chip and a collet for adsorbing or holding the semiconductor chip,
A chip heating head according to claim 1, wherein the collet has a distribution in a heat transfer capacity to the semiconductor chip by providing a hollow portion within the collet.

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