JP2004128233A - Suction nozzle and die bonding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suction nozzle having a thin heater, which attains position recognition with high precision without widely shielding the visual field of an objective lens for position recognition, and to provide die bonding equipment employing the suction nozzle. <P>SOLUTION: A position recognition optical system 40 is arranged above the suction nozzle which is provided with a nozzle tip 1 of a knife ridge shape that narrows as it extends from an upper surface to a lower surface, a long and narrow heater plate 2, a long and narrow heat insulating plate 3, and a collet 4 having a long and narrow support 4a for supporting the foregoings. With this arrangement, an optical path 41 is recured at least passing through the vicinity of the optical axis of the optical system 40 and through windows 5a, 5b of the collet 4 in a plane vertically crossing in the longitudinal direction of the support 4a, the optical path 41 includes therein the support 4a, the heat insulating plate 3, the heater plate 2 and the nozzle tip 1. Thus, the position recognition on a substrate 30 is made possible. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a die bonding apparatus and a suction nozzle for positioning a semiconductor element, particularly an optical semiconductor element requiring high-precision positioning, at a predetermined position on a substrate and fixing the semiconductor element at that position while heating.
[0002]
[Prior art]
In a conventional die bonding apparatus, a semiconductor element is suctioned by a suction nozzle, and then the semiconductor element is pressed to a desired position on the substrate surface, and then the solder on the substrate is heated using a heating stage on which the substrate is mounted. By melting, the semiconductor element is fixed on the substrate (for example, see Patent Document 1). The operation procedure of this conventional die bonding apparatus will be described with reference to FIG. First, as shown in FIG. 5A, the substrate 130 is arranged below the element 120 sucked by the suction nozzle 110 using the movable table 152. Next, the position recognition optical system 140 is inserted between the element 120 and the substrate 130, and the upper solid-state imaging element 140b is positioned directly below the two marks 121 formed on the lower surface of the element 120. The position of the mark 121 is recognized. Next, as shown in FIG. 1B, the position recognition optical system 140 is retracted to position the lower solid-state imaging device 140c directly above the two marks 131 formed on the upper surface of the substrate 130, Both marks 131 are recognized. From these two recognitions, the relative positional relationship between the element 120 and the substrate 130 is calculated, and how much the positional relationship deviates from the desired positional relationship is calculated. Subsequently, the substrate 130 is moved by using the movable table 152 so as to offset the displacement. Then, the relative positional relationship between the element 120 and the substrate 130 is confirmed again using the position recognition optical system 140 in the same manner as described above. This operation is repeated until the displacement becomes zero. At the time when the displacement becomes zero, the position recognition optical system 140 is evacuated, the suction nozzle 110 is lowered, and the element 120 held therein is moved to the solder 132 and the substrate 130. Then, the solder 132 is melted by the heating stage 150 and the element 120 is bonded to the substrate 130.
[0003]
However, in the above-described related art, the axis of measurement caused by recognizing the element 120 and the substrate 130 by the different solid-state imaging devices 140b and 140c, the play of the apparatus when the position recognition optical system 140 is moved, and the like. And the need to recognize the element 120 and the substrate 130 a plurality of times by the solid-state imaging device.
[0004]
Therefore, a die bonding apparatus capable of solving these problems has been proposed (for example, see Patent Document 2). FIG. 6 is a front sectional view of a suction nozzle of the conventional die bonding apparatus. As shown in FIG. 6, this conventional suction nozzle includes a nozzle chip 201 for sucking and holding an element 220, a light-transmitting support member 211 for supporting the nozzle chip 201, and a suction member between the light-transmitting support member 211. It comprises a light transmissive cover member 212 forming the chamber 207, and a cylindrical collet 204 holding the light transmissive support member 211 and the light transmissive cover member 212. The suction hole 206 of the nozzle chip 201 is connected to the suction chamber 207 and the suction chamber port 207a. By connecting a suction pump (not shown) to the suction chamber port 207a, the suction hole 206 of the nozzle chip 201 is connected to the suction chamber 206. The element 220 can be adsorbed. In order to fix the element to the substrate using the bonding apparatus having the conventional suction nozzle, first, a position recognition optical system (not shown) in which the central axis is arranged coaxially with the collet 204 above the collet 204. Is used to recognize the position of the element 220, and the suction nozzle is positioned to suck the element 220. Next, the substrate 230 was moved below the element 220, and after a desired element fixing position of the substrate 230 was recognized using the position recognition optical system, the suction nozzle was positioned and the element 220 was coated with silver paste. Lower to the element fixing position. Finally, the substrate 230 is taken out of the bonding stage 260, and in a separate process, the silver paste is heated and cured using an electric oven or the like, and the element 220 is finally fixed to the substrate 230.
[0005]
[Patent Document 1]
JP-A-06-216170 (page 3, FIG. 1)
[Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-299501 (Pages 4-6, FIGS. 3, 4, 5, 9, 11, and 15)
[0006]
[Problems to be solved by the invention]
However, the die bonding apparatus disclosed in Japanese Patent Application Laid-Open No. 06-216170 heats the substrate using only the heating stage on which the substrate is mounted, and has no heating means on the suction nozzle side. In addition, there is also a problem that the element cannot be preheated before being fixed to the substrate, and it takes time for die bonding. When a plurality of elements are fixed to a single substrate, the entire substrate must be heated even when the elements to be mounted later are fixed. There is also a problem that misalignment occurs. In addition, when a plurality of elements having different heat resistances are mounted, there is a problem that the mounting order is restricted.
[0007]
On the other hand, in the die bonding apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-299501, after the substrate on which the element is mounted is taken out from the bonding stage, the position of the element is displaced until the silver paste is finally heated and cured. There is a risk of happening. Further, in this die bonding apparatus, it is necessary to increase the magnification of the optical system in order to perform position recognition with high accuracy, and a high-magnification objective lens is used. The working distance between the lens tip and the in-focus position is shortened. For example, in the case of an objective lens having a magnification of 20 times, the working distance is about 20 mm even if the objective lens corresponds to a long working distance. For this reason, the suction nozzle, which is disposed directly below the objective lens and coaxially with the objective lens, needs to be housed at a height of more than ten mm, excluding the vertical operation range of the nozzle. Therefore, there is a problem that it is difficult to add a heating mechanism to the suction nozzle without largely obstructing the field of view of the position recognition optical system.
[0008]
The present invention has been made in view of the above problems, and has as its object to provide a suction nozzle incorporating a heating means without largely obstructing the field of view of a position recognition optical system, and a die bonding apparatus using the suction nozzle. To provide.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, there is provided a suction nozzle for adsorbing an object to be adsorbed, the nozzle tip having a surface for fixing the object to be adsorbed, and the nozzle chip being held on a lower surface. A suction nozzle having a plate-like heater plate is provided.
More preferably, the nozzle tip is narrower in width from the upper surface to the lower surface, and a plate-shaped heat insulating plate for holding the heater plate on the lower surface, on the plate-shaped heater plate, And a collet having a plate-like holding portion for holding the plate on the lower surface.
[0010]
In order to achieve the above object, according to the present invention, there is provided the suction nozzle, and an optical system for recognizing a position of a substrate or a lead frame to which an object to be suctioned is fixed by the suction nozzle. A die bonding apparatus, wherein the optical system is provided above the suction nozzle or by inserting a part of the collet into the collet of the suction nozzle and passing through the optical axis of the optical system. A die bonding apparatus is provided in which a holding portion of the collet, a heat insulating plate, a heater plate, and a nozzle chip are disposed in a light path on a plane orthogonal to the longitudinal direction.
[0011]
〔effect〕
The suction nozzle according to the present invention includes a nozzle chip having a surface for fixing the suctioned object to be sucked, and a nozzle chip heating means including a plate-like heater plate for holding the nozzle chip on a lower surface. Thus, it is possible to fix the element to the substrate in a short time and to fix the plurality of elements with high positional accuracy.
[0012]
The die bonding apparatus according to the present invention is configured to include most of the suction nozzle except for the collet in the optical path of the position recognition optical system. This enables highly accurate position recognition of the element at the element suction position and high accuracy position recognition of the substrate at the element fixed position. The suction nozzle according to the second aspect makes it possible to realize such a die bonding apparatus.
[0013]
In the suction nozzle according to the third aspect, the width of the nozzle tip becomes narrower from the upper surface to the lower surface, whereby the temperature of the element to be sucked can be increased uniformly and efficiently.
In the suction nozzle according to the fourth aspect, the heater plate is formed of a self-heating element, thereby realizing a suction nozzle in which a thin heater plate is inserted.
In the suction nozzle according to the sixth aspect, the suction path is formed so as to penetrate the respective parts forming the suction nozzle, so that the formation of an extra suction path is unnecessary and the suction nozzle is small and thin. A nozzle can be realized.
The suction nozzle according to claim 7, wherein the nozzle tip, the heater plate, and the heat insulating plate are connected to each other and provided with a displacement prevention pin, whereby each member of the nozzle chip, the heater plate, and the heat insulating plate is provided. The deformation and displacement of the nozzle chip, the heater plate, and the heat insulating plate caused by the difference in thermal expansion coefficient of the nozzle chip are suppressed, and the element sucked on the lower surface of the nozzle chip is positioned with high accuracy.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front sectional view of a suction nozzle according to the present invention. FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a bottom view of FIG. Throughout the drawings, the same portions are denoted by the same reference numerals. The suction nozzle 10 according to the present invention includes a nozzle chip 1, an elongated plate-shaped heater plate 2 holding the nozzle chip 1 on the lower surface, an elongated plate-shaped heat insulating plate 3 holding the heater plate 2 on the lower surface, and a heat insulating plate. And a collet 4 having an elongated plate-like holding portion 4a for holding the lower surface 3 at the lower surface. The nozzle chip 1, the heater plate 2, and the heat insulating plate 3 are formed with suction holes 6 penetrating therethrough and having suction hole ports 6a on the front end plane of the nozzle chip 1. The nozzle tip 1, the heater plate 2, and the heat insulating plate 3 are also provided with a displacement prevention hole 8 into which a displacement prevention pin 9 connecting them is fitted. The holding portion 4a of the collet 4 is formed with a suction groove 7 extending from the opening of the suction hole 6 on the heat insulating plate 3 side to the suction groove opening 7a on the left end of the drawing. The nozzle tip 1 has a truncated pyramid shape in which the length and width are reduced from the upper surface, which is the attachment portion to the heater plate 2, toward the nozzle tip where the suction hole 6a is formed. On the bottom surface of the collet 4, windows (openings) 5a and 5b are open except for the holding portion 4a. Glass or resin such as acrylic may be fitted into the windows 5a and 5b.
[0015]
The suction nozzle according to the present invention having such a configuration is attached to the die bonding apparatus main body so as to be vertically movable. By connecting a suction pump (not shown) to the suction groove orifice 7a and performing suction, a semiconductor element or the like placed in contact with or near the bottom surface of the nozzle chip 1 can be sucked into the suction hole 6a of the nozzle chip 1. It can be adsorbed and fixed to its bottom surface.
[0016]
By using a material (self-heating element) such as SiC ceramics that generates heat by energization for the heater plate 2, the heater plate 2 can be easily formed into a thin and thin plate shape. Heating is performed on a semiconductor element or the like fixed to the bottom surface of the nozzle chip 1 by applying current through electrode portions (not shown) formed at both ends in the longitudinal direction of the thin plate-shaped heater plate 2. Can be.
[0017]
The lower surface of the heater plate 2 and the upper surface of the nozzle chip 1 are made of a material such as AlN ceramics, which is an electrical insulator and conducts heat well, except for both ends where the electrode portions of the heater plate 2 are formed. The heat is efficiently transmitted to the tip of the nozzle tip 1 by adopting a structure in which the nozzle tip 1 makes wide contact. Further, since the nozzle tip 1 has a truncated pyramid shape that gradually becomes thinner toward the tip of the nozzle tip, the temperature rise at the tip of the nozzle tip due to heat from the heater plate 2 increases, and the temperature decreases over the entire lower surface. Becomes uniform. Generally, individual optical elements are small, but a plurality of optical elements are often connected to form a bar-shaped optical element array. Even for such an elongated bar-shaped element array, a uniform and efficient temperature increase can be achieved by forming the nozzle tip into a truncated pyramid shape and making the shape of the tip flat portion of the nozzle tip similarly elongated. Can be.
[0018]
By using a material such as alumina ceramics, which is an electric insulator and has low heat conductivity, for the heat insulating plate 3, heat transfer from the heater plate 2 to the collet 4 is suppressed. Further, the groove 7 formed in the collet 4 has an effect of suppressing heat conduction from the heat insulating plate 3 to the collet 4 in order to reduce the contact area between the holding portion 4a of the collet 4 and the heat insulating plate 3.
[0019]
It is desirable that the misalignment prevention hole 8 be formed so as to overlap the central axis of the suction nozzle 10. In this case, when heating and cooling by the heater plate 2, the nozzle chip 1, the heater plate 2, and the heat insulating plate 3 are generated due to the difference in the coefficient of thermal expansion between the members of the nozzle chip 1, the heater plate 2, and the heat insulating plate 3. 3 can be minimized, and the element sucked on the lower surface of the nozzle tip 1 can be positioned with high accuracy. However, when the suction hole 6 is formed near the center axis of the suction nozzle 10, the position shift prevention hole 8 can be arranged so as to be shifted from the center axis. Even in such a case, it is desirable that the displacement prevention hole 8 is formed as close to the central axis as possible.
[0020]
Next, the operation of the entire suction nozzle according to the present invention will be described in more detail with reference to FIG. FIG. 4 is a sectional view for explaining the operation of the suction nozzle according to the present invention. 4, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and overlapping descriptions will be omitted as appropriate. FIG. 4 shows a state in which the element 20 is sucked and held at the tip of the nozzle tip. Further, a tip portion of the position recognition optical system 40 disposed immediately above the suction nozzle 10 is inserted into the collet 4 with their central axes coaxial. An objective lens 40a is provided at the tip of the position recognition optical system 40, and the position on the substrate 30 can be confirmed by the position recognition optical system 40. At this time, the holding portion 4a of the collet 4, the heat insulating plate 3, the heater plate 2, the nozzle chip 1, and the element 20 are located immediately below the objective lens 40, and a part of the visual field of the objective lens 40a is blocked. However, the nozzle chip 1 has a long and narrow truncated pyramid shape whose length and width gradually decrease toward the tip thereof, and the element 20 is also adsorbed in the lower surface of the nozzle chip 1. On a plane passing near the optical axis of the system 40 and orthogonal to the longitudinal direction of the collet holding portion 4a, the holding portion 4a of the collet 4, the heat insulating plate 3, the heater plate 2, and the pyramid are passed through the windows 5a and 5b of the collet 4. The optical path 41 including the trapezoidal nozzle chip 1 inside is secured, and the position on the substrate 30 placed on the heating stage 50 can be recognized. Similarly, when the element 20 is sucked to the tip of the nozzle tip, it is apparent that the position of the element 20 placed on the element mounting table can be recognized.
[0021]
Therefore, if the suction nozzle is incorporated in the bonding apparatus in the state shown in FIG. 4, the position of the element can be recognized / positioned at the time of element suction, and the element can be sucked by moving the suction nozzle up and down at that position. . In addition, the position of the substrate can be recognized / positioned when the element is fixed to the substrate, and the suction nozzle can be vertically moved and fixed at that position. A eutectic alloy, solder, silver paste, or the like is applied to predetermined positions of the substrate in advance. Since the suction nozzle only slightly moves up and down when the element is sucked and fixed, it is possible to fix the element with high positional accuracy. Further, since the suction nozzle is provided with the heating means, it is possible to preheat the element before fixing to the substrate, and it is possible to perform good fixing in a short time. When a plurality of elements are fixed to one substrate, the elements can be heated only by the heating means of the suction nozzle without heating the substrate. There is no possibility that the solder or the like of the element which is positioned and fixed with high precision is melted and displaced. Alternatively, in a case where a plurality of elements are fixed to one substrate, when fixing the elements in the second and subsequent layers, the substrate is heated to a temperature equal to or lower than the heating temperature of the previously fixed element, and the suction nozzle is heated as necessary. The element may be further fixed on the substrate by further heating the element using a means. Furthermore, even when an element having a low heat-resistant temperature is already mounted on the substrate, the element adsorbed on the tip of the nozzle chip can be heated and fixed to the substrate only by the heating means of the suction nozzle. Therefore, an element having a low heat-resistant temperature can be fixed to the substrate first, and there is no restriction on the order of mounting the elements on the substrate.
[0022]
As described above, the bonding apparatus according to the present invention can perform high-precision position recognition of the element at the element suction position and high-precision position recognition of the substrate at the element fixing position. Since it is possible, the present invention can be applied to the assembly of an optical semiconductor element or the like that requires high-precision positioning on the order of μm.
[0023]
As described above, the present invention has been described based on the preferred embodiments. However, the suction nozzle of the present invention and the die bonding apparatus using the same are not limited to only the above-described embodiments, and the present invention is not limited thereto. Suction nozzles that have undergone various changes within a range that does not change the gist and die bonding apparatuses using the same are also included in the scope of the present invention. For example, the heater plate is not limited to a self-heating type material, but may be a material in which a fine heating wire is embedded in an insulating material, and the heater plate is thin and thin enough to fit in the optical path of the position recognition optical system. Any one can be used. At this time, a metal material or the like that is not necessarily an electrical insulating material may be used for the nozzle tip. Further, the nozzle chip, the heater plate, the heat insulating plate, and the holding portion of the collet do not need to be formed to be thin in the entire area thereof, and as long as the position recognition optical system can confirm the position on the substrate, the position recognition is particularly required. Any shape may be formed outside the optical path of the optical system. In addition, the suction groove of the holding portion of the collet does not necessarily need to be provided in a straight line from the opening of the suction hole on the heat insulating plate side. The suction means may be formed in any shape as long as it constitutes a piping passage through which the element can be sucked into the suction hole of the nozzle chip. Further, the suction groove may be provided not on the holding portion of the collet, but on the heat insulating plate, or over the holding portion of the collet and the heat insulating plate. In particular, when the temperature of the heater plate is not raised so much as in the case where the heating stage on which the substrate is placed is used as the main heating source and the heater plate is used as the auxiliary heating source, the influence of the difference in thermal expansion is small. The formation of the shift prevention holes and the installation of the position shift prevention pins may be omitted. Further, the center axis (optical axis) of the position recognition optical system and the center axis of the suction nozzle do not necessarily need to coincide with each other, as long as the amount of axis shift is known. Further, the substrate to which the element is fixed may be a lead frame. Furthermore, in order to control the temperature at the tip of the nozzle tip, the temperature of the thermocouple or the like should be set at a position not obstructing the field of view of the position recognition optical system, such as the longitudinal end of the nozzle tip or between the heater plate and the nozzle tip. A sensor may be provided.
[0024]
【The invention's effect】
As described above, the suction nozzle according to the present invention includes the nozzle chip having the surface for fixing the suctioned object to be sucked and the heating means for heating the nozzle chip. It is possible to fix the element to the substrate and to fix the plurality of elements with high positional accuracy.
[0025]
In addition, the die bonding apparatus according to the present invention is configured to include most of the suction nozzle except for the collet in the optical path of the position recognition optical system. And highly accurate position recognition of the substrate at the element fixing position.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a suction nozzle according to the present invention.
FIG. 2 is a sectional view taken along the line AA in FIG. 1;
FIG. 3 is a bottom view of FIG. 1;
FIG. 4 is a cross-sectional view for explaining the operation of the suction nozzle according to the present invention.
FIG. 5 is a front view of a main part of a conventional die bonding apparatus.
FIG. 6 is a cross-sectional view of a conventional suction nozzle.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Nozzle chip 2 Heater plate 3 Heat insulation plate 4 Collet 4a Holding part 5a, 5b Window 6 Suction hole 6a Suction hole 7 Suction groove 7a Suction groove opening 8 Position prevention hole 9 Position prevention pin 10 Suction nozzle 20 Element 30 Substrate 40 Position Recognition optical system 40a Objective lens 41 Optical path 50 Heating stage 110 Suction nozzle 120 Element 121, 131 Mark 130 Substrate 132 Solder 140 Position recognition optical system 140b, 140c Solid-state imaging device 150 Heating stage 152 Movable table 201 Nozzle chip 206 Suction hole 207 Suction chamber 207a Suction chamber opening 211 Light transmitting support member 212 Light transmitting cover member 220 Element 230 Substrate 260 Bonding stage

Claims (10)

An adsorption nozzle for adsorbing an object to be adsorbed, comprising: a nozzle chip having a surface for fixing the adsorbed object to be adsorbed; and a plate-shaped heater plate for holding the nozzle chip on a lower surface. Suction nozzle. The suction nozzle according to claim 1, further comprising: a plate-shaped heat insulating plate that holds the heater plate on a lower surface; and a collet that has a plate-shaped holding portion that holds the heat insulating plate on a lower surface. The suction nozzle according to claim 1, wherein the nozzle chip has a width that is at least partially reduced from an upper surface to a lower surface. The suction nozzle according to any one of claims 1 to 3, wherein the heater plate is a self-heating element. The suction nozzle according to claim 4, wherein the nozzle tip and the heat insulating plate are electrical insulators. A suction hole is provided through the nozzle tip, the heater plate, and the heat insulating plate, and is connected to the suction hole, and the collet holding portion or / and the heat insulating plate is provided with the collet holding portion or / The suction nozzle according to any one of claims 2 to 5, wherein a groove reaching the outer wall of the heat insulating plate is provided. 7. A misalignment prevention hole in which a misalignment prevention pin is fitted is formed over the nozzle tip, the heater plate, and the heat insulating plate. Suction nozzle. A die bonding apparatus comprising: the suction nozzle according to any one of claims 2 to 7; and an optical system for recognizing a position of a substrate or a lead frame to which an object to be sucked adsorbed by the suction nozzle is fixed. The optical system is inserted above the suction nozzle or a part of the collet of the suction nozzle, and passes through the optical axis of the optical system, and is orthogonal to the longitudinal direction of the holding portion of the collet. A die bonding apparatus, wherein a holding portion of the collet, a heat insulating plate, a heater plate, and a nozzle chip are arranged in a plane so as to be included in an optical path. 9. The die bonding apparatus according to claim 8, wherein a center axis of the optical system coincides with a center axis of the suction nozzle. A bonding stage for mounting the substrate or the lead frame when the object to be suctioned by the suction nozzle is fixed to the substrate or the lead frame has a function of heating the substrate or the lead frame. The die bonding apparatus according to claim 8 or 9, wherein

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