JP3978889B2 - Bump electrode bonding strength test equipment and test method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bonding strength test apparatus and test method for bump electrodes constituting a semiconductor or a semiconductor device, and more particularly to a test apparatus and test method for tensile strength of solder balls of a BGA (ball grid array).
[0002]
[Prior art]
With the spread of high-density mounting, as a tensile strength test apparatus or test method for bump electrodes (including bumps, for example, substantially spherical solder balls, plating layers, copper foil patterns, etc.) constituting semiconductors or semiconductor devices, A method of pulling a semiconductor or an entire semiconductor device or connecting a probe and a bump with an adhesive is used.
Japanese Patent Application Laid-Open No. 8-111417 proposes a bonding strength test method and apparatus in which a probe abutting against a bump constituting a semiconductor is heated and bonded, the probe is pulled, and the bonding strength is measured.
[0003]
[Problems to be solved by the invention]
A test method when, for example, a BGA is used as a semiconductor device will be described using the method disclosed in JP-A-8-111417.
In this case, solder balls are used as bumps constituting the bump electrodes, and the peripheral structure is generally as shown in FIG.
In measuring the tensile strength of the bump electrode, first, the base material 20 of the semiconductor device is fixed. Next, the probe is fixed (connected / adhered) to the solder ball 17 and pulled upward to peel the solder ball 17 from the substrate 20.
[0004]
In the tensile strength measurement at room temperature, there are many modes in which the copper foil 19 peels from the base material 20. On the other hand, one of the problems associated with BGA solder balls is that the bonding strength between the plating 18 and the solder balls 17 is reduced in a high temperature state such as during reflow soldering, and in combination with the warpage of the package, in the worst case, peeling. There is a phenomenon.
In this case, the peeling portion naturally occurs at the interface between the plating 18 and the solder ball 17. When this phenomenon occurs, measures such as improving the plating specifications are taken.
However, even if it is going to verify the effect of the said countermeasure, destruction will arise between copper foil and a base material in the conventional tensile strength test performed at normal temperature.
As a result, it was impossible to correctly measure the bonding strength between the plating and the solder balls.
[0005]
An object of the present invention is to accurately measure the bonding strength of a bump electrode in a high temperature state.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a bonding strength test apparatus and a test method for a bump electrode according to the present invention include:
1. In measuring the tensile strength, either one of the semiconductor provided with the bump electrode or the semiconductor device is heated to a predetermined temperature, for example, in the range of 80 ° C to 130 ° C.
2. As a method of bonding and fixing the probe to the bump electrode, any one of a method of bringing a heating iron (鏝) into contact with the probe while the probe is in contact with the bump electrode, or a light beam, a laser beam, hot air, etc. The bump electrode was melted and bonded using a heating means.
3. The probe had a configuration in which a metal part (copper or copper alloy) and a thermal insulator part (resin member) were connected.
[0007]
With the above configuration, the present invention can accurately measure the bonding strength of the bump electrode at a high temperature.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided a stage for fixing any one of a semiconductor having a bump electrode or a semiconductor device having a bump electrode, means for heating the semiconductor or the semiconductor device, and a probe for the bump electrode. And a bonding strength measuring device for measuring the tensile strength of the bump electrode by pulling the probe, and a bump electrode bonding strength test apparatus characterized by comprising: Can be measured accurately.
[0009]
Further, the second invention is the bump electrode bonding strength test apparatus according to the first invention, characterized in that the probe comprises a metal part and a thermal insulator part. Heat transfer is difficult.
[0010]
Further, the third invention is characterized in that a thermal insulator is disposed between the heater and the stage so that the heat of the planar heater is not conducted to the stage, and the bonding strength of the bump electrode according to the first invention is characterized in that This is a test device that prevents the temperature of the test device from rising.
[0011]
Further, the fourth invention is the bump electrode bonding strength test apparatus according to any one of the first to third inventions, characterized in that the tensile strength measuring means is a push-pull gauge, and the measuring means is simple and inexpensive. It becomes.
[0012]
Further, the fifth invention is a test method for measuring the tensile strength of a bump electrode, wherein a probe is bonded to either a bump electrode constituting a semiconductor or a bump electrode constituting a semiconductor device, and the semiconductor or The bump electrode test method is characterized in that the tensile strength of the bump electrode is measured while the semiconductor device is heated to a predetermined temperature, and the bonding strength of the bump electrode at high temperature can be accurately measured. .
[0013]
Further, in the fifth invention, the bump electrode and the probe are bonded to each other by using any one of heating means such as a heat beam, a light beam, a laser beam, and hot air for the probe in contact with the bump electrode. The bump electrode testing method according to the fifth aspect of the invention is characterized in that the bump can be melted simply and quickly.
[0014]
A bump electrode bonding strength test apparatus and test method according to an embodiment of the present invention will be described below with reference to the drawings.
[0015]
【Example】
FIG. 2 is a side view of the concept showing the overall configuration of a bonding strength test apparatus for bump electrodes of a semiconductor or semiconductor device according to an embodiment of the present invention.
In FIG. 2, the bump electrode bonding strength test apparatus includes a base 10, a leg 11, and a support 12, and a heater 2 and a stage 6 for fixing a semiconductor or semiconductor device 1 as a sample are provided on the base 10. Yes.
Further, a movable portion 13 that is vertically movable with respect to the stage 6 by a motor 14 provided at the lower portion of the base 10 is provided on the support column, and the movable portion 13 is provided with a push-pull gauge 9 that measures the tensile strength. ing. A probe 8 is attached to the lower end of the push-pull gauge 9.
[0016]
FIG. 1 is a detailed perspective view of the periphery of a stage portion of a bump electrode bonding strength test apparatus according to the present invention.
The semiconductor or semiconductor device 1 is fixed to the stage 6 while being in close contact with the heater 2 by the presser plate 3 and screws 7. As the heater in this case, it is desirable to use a planar silicon rubber heater in order to improve adhesion to the semiconductor or the semiconductor device 1. Furthermore, it is more effective to apply silicon grease for heat conduction between the heater 2 and the semiconductor or semiconductor device 1.
In addition, a thermal insulator 4 is disposed between the heater 2 and the stage 6, and a certain gap is provided between the thermal insulator 4 and the stage 6 via a spacer 5.
With the above configuration, thermal insulation of the heater 2 to the stage 6 is ensured, and the thermal efficiency of the heater 2 is improved.
[0017]
The stage 6 is an XY table that arbitrarily moves in a two-dimensional plane, and a plurality of bump electrode strengths can be continuously measured by pulling without removing the semiconductor or the semiconductor device 1.
[0018]
The probe 8 is composed of a combination of a bump (for example, a solder ball) of the bump electrode 100, a metal part having good wettability, and a thermal insulator part.
For example, a copper wire 15 is fixed to a resin 16 as shown in FIG. With this configuration, when the bump electrode 100 constituting the semiconductor or the semiconductor device 1 is heated, heat can be prevented from being radiated through the probe 8.
That is, if the entire probe 8 is made of a metal member, when the probe 8 is in contact with or fixed to the bump electrode, the heat of the semiconductor or the semiconductor device 1 is taken through the probe 8 and the thermal efficiency of the heater is extremely deteriorated. .
[0019]
Next, a procedure for measuring the tensile strength of the bump electrode 100 will be described. First, the planar heater 2 is energized to heat the semiconductor or semiconductor device 1 to a desired temperature, for example, in the range of 80 ° C to 130 ° C.
Next, the probe 8 is brought into contact with the bump electrode 100 having the solder balls of the semiconductor or the semiconductor device 1. In this state, a hot iron (プ ロ ー ブ) is brought into contact with the tip of the probe 8 to melt the solder bump.
At this time, if a flux is applied to the tip of the probe 8, melting is performed quickly. After confirming the melting, the probe 8 and the solder bump are fixed by removing the heating iron.
[0020]
Subsequently, while the semiconductor or semiconductor device 1 is kept in the range of about 80 ° C. to 130 ° C., the movable portion 13 of the bonding strength test apparatus is moved, and the probe 8 fixed (adhered) to the push-pull gauge 9 and the solder bump. Is pulled in the direction perpendicular to the main plane of the substrate () in the vertical direction, and the tensile strength at the time when the bump electrode 100 is broken is measured.
[0021]
FIG. 5 shows the tensile strength and the failure mode for each temperature of a solder ball of 1.27 mm pitch plastic BGA. The horizontal axis represents the solder ball temperature, and the vertical axis represents the tensile strength.
The case of breaking between the copper foil and the base material is indicated by X, and the case of breaking between the plating and the solder is indicated by ○. It can be seen that the failure mode is strongly dependent on the ball temperature. This is something that could not be known by the conventional test method performed at room temperature.
[0022]
In the above-described embodiment, an example of a method of contacting a hot metal with the probe as a heating and bonding means between the probe and the bump electrode has been described, but it goes without saying that the method is not limited to this. Arbitrary heating means, for example, any one of a light beam, a laser beam, hot air, etc., may be applied to the probe or the bump or the contact portion between the probe and the bump.
Similarly, any members and configurations may be used for the configurations of the bumps and the bump electrodes.
[0023]
【The invention's effect】
With the above configuration, the present invention can accurately measure the bonding strength of the bump electrode at a high temperature.
The probe is composed of a combination of a bump metal of the bump electrode, a metal having good wettability, and a thermal insulator, and a configuration in which the planar heater for heating the semiconductor or the semiconductor device 1 is thermally insulated from the stage. The thermal efficiency of the planar heater is very good.
Furthermore, by using an XY table as the stage, the strength of a plurality of bump electrodes can be measured continuously without removing the semiconductor or the semiconductor device 1, and the working efficiency is excellent.
Further, the use of a general push-pull gauge as a means for measuring the tensile strength makes it possible to configure the joint strength test apparatus at a low cost.
Further, when a hot metal is used for bonding the probe and the bump electrode, the probe heating mechanism is not required, and the bonding strength test apparatus can be configured at low cost.
[Brief description of the drawings]
FIG. 1 is an enlarged perspective view of a stage portion constituting a bump electrode bonding strength test apparatus according to an embodiment of the present invention. FIG. 2 is a side view of a concept of a bump electrode bonding strength test apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of the probe constituting FIG. 2. FIG. 4 is a schematic side view of a BGA solder ball joint. FIG. 5 is a characteristic diagram of tensile strength measured using FIG.
DESCRIPTION OF SYMBOLS 1 Semiconductor or semiconductor device 2 Heater 3 Holding plate 4 Thermal insulator 5 Spacer 6 Stage 7 Screw 8 Probe 9 Push-pull gauge 10 Base 11 Leg 12 Strut 13 Movable part 14 Motor 15 Copper wire (metal part)
16 Resin (thermal insulator part)
17 Solder balls (bump)
18 Plating 19 Copper foil 20 Base material 100 Bump electrode

Claims (12)

A stage for fixing any one of a semiconductor provided with a bump electrode or a semiconductor device provided with a bump electrode, a heating means for heating the semiconductor or the semiconductor device, a probe bonded to the bump electrode, and pulling the probe A bump electrode bonding strength testing device comprising a bonding strength measuring means for measuring the bonding strength of the bump electrode,
Bonding strength test device characteristics and to Luba pump electrodes that said probe consists of a metal part and the thermal insulation portion. 2. The bump electrode bonding strength test apparatus according to claim 1 , wherein the probe is formed by bonding the bump electrode, a metal part having good wettability, and a thermal insulator part made of a resin member. 2. The bump electrode bonding strength test apparatus according to claim 1, wherein the heating means is a planar heater. 4. The bump electrode bonding strength test apparatus according to claim 3, wherein the planar heater is a silicon rubber heater. As the heat of the planar heater are not conducted to the stage, bumps according to any one of claims 3-4, characterized in that a heat insulator between the planar heater with the stage Electrode bonding strength test equipment. As the heat of the planar heater is not conducted to the stage, the bonding strength according to claim 5, wherein the bump electrodes through the spacer, characterized in that it has a certain gap between the stage and the heat insulator Test equipment. Bonding strength test device of the bump electrode according to any one of claims 1 to 6, wherein the stage is characterized in that the XY table for moving in a horizontal plane vertically and horizontally. Thermal trowel as heat bonding means for bonding said probe to said bump electrodes, the light beam, a laser beam, according to any one of claims 1 to 7, characterized in that using any one of the hot air Bump electrode bonding strength test equipment. The apparatus for testing a bonding strength of a bump electrode according to any one of claims 1 to 8 , wherein the bonding strength measuring means is a push-pull gauge. A bonding strength test method for measuring the bonding strength of a bump electrode, wherein a probe comprising a metal portion and a thermal insulator portion is bonded to either a bump electrode constituting a semiconductor or a bump electrode constituting a semiconductor device. and bonding step, the bonding of the semiconductor or a heating step of heating the semiconductor device to a predetermined temperature, the bump electrode and having a bonding strength measuring step of measuring the bonding strength of the bump electrode by pulling the probe Strength test method. It said heating step, the bonding strength test method according to claim 1 0, wherein the bump electrode, characterized in that the said semiconductor or range of 80 ° C. to 130 DEG ° C. The temperature for heating either of the semiconductor device. The adhesive step, Netsu鏝, light beam, according to claim 10 to 1 1, characterized in that the laser beam, and so as to bond the said probe and the bump electrode using any one of heat bonding means of hot air The bonding strength test method for a bump electrode according to any one of the above.

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