JP2002082144A - Measuring method for electrical characteristics of semiconductor package, and test handler for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method in which the electrical characteristics of semiconductor packages having different thicknesses is measured, and to provide a test handler for the method. SOLUTION: A plurality of solar balls (4) as electrodes of a package (1) attached and bonded to the bottom face of the handler arm (9) of the test handler are brought into contact with a plurality of spring probes (10) as contactors of the test handler. A pressure force is loaded between them. The solder balls and the spring probes are electrically connected. The pressure force applied to the package (1) is measured by a pressure sensor (14) attached to the handler arm (9), and the handler arm (9) is controlled, in such a way that the measured pressure force agrees with a proper pressure force value which has been set. While the pressure force is being controlled so as not to exceed the set pressure force value, the electrical characteristics of the package (1) are measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the electrical characteristics of a semiconductor package mounted on various electric and electronic devices,
The present invention relates to a method for measuring electrical characteristics for evaluating the quality of these packages, and a test handler therefor.

[0002]

2. Description of the Related Art The use of semiconductor packages has led to miniaturization of various electric and electronic devices.
(Grid Array) package is widely used. In such a semiconductor package, it is necessary to measure various electrical characteristics in order to suppress variation in quality. This measurement is generally performed by applying an appropriate pressing force to the electrodes of the semiconductor package and the contactors of the test handler, which is an apparatus for measuring the electrical characteristics of the semiconductor package, and electrically connecting them. Here, a conventional technique using this method will be described with reference to FIGS.

First, the configuration of a BGA package (hereinafter, package) 1 will be described with reference to FIG. 3A is a top view of the package 1, FIG. 3B is a side view, and FIG. 3C is a bottom view. The package 1 has a thin and substantially flat plate-like substrate 2, a semiconductor element (not shown) mounted thereon, and a substrate 2 so as to seal the entire semiconductor element. The cap 3 has a substantially flat upper surface. Also, a plurality of solder balls 4 arranged as electrodes of the package 1 are attached in a lattice shape so as to protrude from the bottom surface of the substrate 2 and are electrically connected to electrode pads of the semiconductor element, respectively. .

[0004] The type of package includes the size of the outer shape, the pitch of the electrodes, the number of electrodes, the structure of the substrate,
It may change depending on the structure of the cap.

Next, the configuration and operation of the test handler will be described with reference to FIGS. The test handler is connected to the measurement board 6 as shown in FIGS.
And a wiring board 7 mounted thereon, a socket housing 8 mounted thereon,
A plurality of contactors mounted on the housing 8 and electrically connected to the wiring substrate 7 and in contact with the electrodes of the package 1 and electrically connected thereto; holding the package 1 and controlling the movement thereof And a handler arm 9 which performs the operation. A spring probe 10 is used for this contactor.

Next, the structure of the spring probe 10 will be described with reference to FIG. As shown in the figure,
The spring probe 10 has a cylindrical barrel 11 having openings at both ends, and a pair of plungers which are slidably housed at both ends of the barrel 11 and whose tips project outward from the openings. 12 and these plungers 12
And a compression coil spring 13 which is housed in the barrel 11 so as to be positioned therebetween and urges both plungers 12 outward.

[0007] One end of the plunger 12 is shown in FIG.
As shown in FIG. 3, the wiring board 7 is electrically connected to a predetermined wiring portion (not shown) of the wiring board 7, and the other end is
It is electrically connected to the solder balls 4 of the package 1.

Hereinafter, the operation of the test handler having the above configuration will be described with reference to FIG.

First, as shown in FIG. 4A, a columnar handler arm 9 is held on a bottom surface of the socket housing 8 with a flat portion of the upper surface of the cap 3 of the package 1 held by vacuum suction. It is positioned immediately above it with a predetermined gap. That is, the plurality of solder balls 4 of the package 1 and the plurality of spring probes 10 of the test handler are positioned so as to face each other with a certain interval.

Next, as shown in FIG. 4B, the handler arm 9 is lowered at an appropriate speed by an appropriately set constant distance L1, and a plurality of opposed solder balls 4 and a plurality of spring A pressing force is applied between the probe 10 (plunger 12) and the probe 10 is electrically connected. The pressing force between them is balanced by the spring reaction force of the compression coil spring 13. When the amount of compression of the compression coil spring 13 after the contact between the solder ball 4 and the spring probe 10 becomes L2 (≦ L1), the operation is stopped.

When the compression amount of the compression coil spring 13 is L2
Is held, a signal is transmitted from the measurement board 6 of the test handler to measure the electrical characteristics of the package 1, and the quality of the package 1 is evaluated. After the measurement is performed, the handler arm 9 is moved up by the fixed distance L1 to be disposed immediately above the spring probe 10, and the solder ball 4 and the spring probe 10 are again returned to a state where they are opposed to each other (FIG. 4). (A)).

The handler arm 9 releases the suction of the package 1 whose electrical characteristics have been measured and sends the package 1 to the next step. In order to measure the electrical characteristics of another package, the upper surface of the cap attached to this package is measured. The flat part is vacuum-adsorbed and transported, and the above operation is repeated. With these operations, the electrical characteristics of the semiconductor package can be measured one after another.

Further, the spring probe 10 manufactures the compression coil spring 13 under certain conditions,
One spring probe 10 and one spring probe 10 are determined by the relationship between the compression amount L2 of the compression coil spring 13 and the spring reaction force.
The pressing force Cp applied between the two solder balls 4 can be obtained. FIG. 7 shows the relationship when the pressing force Cp is plotted on the vertical axis and the amount of compression L2 after contact with these is plotted on the horizontal axis. FIG. 8 shows the relationship when the pressing force Cp is plotted on the vertical axis and the contact resistance Rc between one solder ball and one spring probe is plotted on the horizontal axis.

As shown in FIG. 7, the pressing force Cp increases almost in proportion to the compression amount L2, and the unit of the compression amount L2 is m
Assuming that the unit of m and the pressing force Cp is N, the relationship between Cp and L2 is shown as a substantially straight line as expressed as Cp = L2.

Further, as shown in FIG. 8, when the pressing force Cp is about 0.13 N or less, the contact resistance Rc shows an unstable behavior, but the pressing force Cp is about 0.13 N or more. In this case, the contact resistance Rc shows a substantially constant value (about 0.1Ω). Therefore, the pressing force Cp is about 0.13 N
(The compression amount L2 is required to be about 0.13 mm) or more, and the pressing force can be applied to such an extent that the solder balls 4 do not give appearance defects such as contact marks.

[0016]

However, in the conventional method for measuring the electrical characteristics of the package, as shown in FIG. 4, the handler arm 9 holding the package by vacuum suction is provided with a socket housing. 8 and is moved by a fixed distance L1 after stopping and applying a pressing force between the electrode of the package and the contactor of the test handler, and is electrically connected. The pressing force applied between the electrode and the contactor varies depending on the type, and has the following problems.

The thickness A of the package 1 shown in FIG.
Variations occur due to factors such as differences in the number of materials in the semiconductor manufacturing process, variations in assembly conditions, and human factors. Due to this variation, the contact position (height) between the solder ball 4 and the spring probe 10 fluctuates.
The compression amount L2 of the compression coil spring 13 constituting the spring probe 10 varies. For example, when the thickness of the package 1 is larger than the standard thickness, the compression amount L2 becomes larger than that of the package having the standard thickness, so that the pressing force increases and a large contact mark or the like is generated on the solder ball 4. In some cases, the reliability of soldering may be reduced. Conversely, when the thickness of the package 1 is smaller than the standard thickness, the compression amount L2 becomes smaller than that of the package having the standard thickness, so that the pressing force decreases and the contact resistance Rc becomes unstable. There is a possibility that the reliability of the result of measuring the electrical characteristics of the package 1 may be reduced. That is, the first problem is that the area array
A conventional method of measuring electrical characteristics cannot cope with a package having a large variation in package thickness.

Generally, in order to measure the electrical characteristics of packages having greatly different thicknesses, an auxiliary member is installed on a test handler to adjust the thickness of the package. However, installing this auxiliary member causes a large time loss, and also requires a space for storing the auxiliary member. That is, the second problem is that the operating distance of the handler arm 9 cannot be controlled according to the thickness of various packages. That is, the handler arm 9 provided in the test handler is required to be compatible with various area array packages having greatly different thicknesses.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to be able to measure the electrical characteristics of a semiconductor product with high reliability even if the package thickness is different. A method and a test handler for this are provided.

[0020]

In order to solve the above-mentioned problems, a method according to the present invention includes a plurality of contactors having a pressing force sensor and incorporated in a socket housing of a test handler for measuring electrical characteristics of a semiconductor package. And a plurality of electrodes of the semiconductor package attached to the handler arm of the test handler, which are electrically connected to each other by pressing them relatively to measure the electrical characteristics of the semiconductor package. A load is applied between a representative one of the plurality of electrodes and a representative one of the plurality of contactors used as a pressure detector that determines an appropriate pressing force facing the electrode. And electrically connecting the contactors with each other, and the contact force with respect to a distance at which the electrode relatively presses the contactor by the pressing force. The contact force, which is the electric resistance of a circuit formed by the electrode and the contactor, is measured for each of the pressing forces, and the electrical characteristics applied between the electrode and the contactor are measured. A first step of setting a predetermined pressing force such that the electrodes do not cause appearance defects, and a second step of calculating a reference pressing force by multiplying the set pressing force by the number of the plurality of electrodes, The semiconductor package is moved by the handler arm, a pressing force is applied between the plurality of electrodes and the plurality of contactors to electrically connect them, and the applied total pressing force is reduced by the pressing force. A third step of controlling the handler arm so that the reference pressing force and the total pressing force are detected by a pressure sensor, and holding the controlled total pressing force, ; And a fourth step of measuring an electrical characteristic of the conductor package.

In order to solve the above problems, a test handler according to the present invention comprises a measurement board, a wiring board, a plurality of contactors, and a handler arm having a pressing force sensor. In a test handler for controlling the movement of the semiconductor package by holding the same by a handler arm and measuring electrical characteristics of the semiconductor package, a representative one of the plurality of electrodes of the semiconductor package and the plurality of A pressing force is applied to a representative one of the contactors to electrically connect them, and the pressing force is applied to the contactor with respect to a distance by which the electrode relatively presses the contactor. The pressing force is measured sequentially, and the electric resistance of the circuit formed by the electrode and the contactor for each pressing force is measured. A first means for measuring a certain contact resistance, setting a predetermined pressing force that can measure an electrical characteristic applied between the electrode and the contactor and does not cause the electrode to have a poor appearance, Second means for calculating a reference pressing force by multiplying the number of the plurality of electrodes, and moving the semiconductor package by the handler arm to apply a pressing force between the plurality of electrodes and the plurality of contactors. And electrically connecting them, detecting the total pressing force, which is the pressing force, by the pressing force sensor, and operating the handler arm such that the reference pressing force matches the total pressing force. A third means for controlling; and a fourth means for measuring the electrical characteristics of the semiconductor package while maintaining the controlled total pressing force.

In order to solve the above problem, in the test handler according to the present invention, the contactor is used as a pressure detector for determining an appropriate pressing force.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 3 to 8
The same reference numerals are used for the same members as those used in the conventional technique shown in FIG.

First, FIGS. 1A and 1B are diagrams corresponding to FIGS. 4A and 4B, respectively, showing a method of measuring the electrical characteristics of a package 1 according to the prior art. In the embodiment shown in FIG. 1, a pressing force sensor 14 for detecting the pressing force applied to the package 1 is added to the handler arm 9 for controlling the movement of the package 1 in addition to the configuration shown in FIG. It was done. That is, the pressing force sensor 14 applies a pressing force between all the solder balls 4 as the electrodes of the package 1 and all the spring probes 10 as the contactors of the test handler (this is a total pressing force ΔCp). ) Is detected, the detected sensor output is converted into an electrical signal, and the output is converted into a numerical value and output.

In this test handler, the package 1 is held on the handler arm 9 by vacuum suction, and the pressing force is controlled by the handler arm 9 by the function of the pressing force sensor 14.

Next, a method of setting the reference pressing force will be described. The reference pressing force is a value obtained by multiplying an appropriate pressing force described later by the number of solder balls 4 as electrodes of the package 1 (here, 1,000).

As shown in the prior art, the contact resistance Rc between one solder ball 4 and one spring probe 10 is almost constant when the pressing force Cp between them is about 0.13 N or more. Was shown. Here, 0.20N, which is a pressing force Cp that gives some margin so that the contact resistance Rc keeps a constant value and does not cause appearance defects such as contact marks on the solder ball 4, is applied to one solder. An appropriate pressing force was applied to the ball 4 and one spring probe 10. That is, the reference pressing force was set to 200N.

In this embodiment, the pressing force Cp applied between one solder ball 4 and one spring probe 10 is determined. If it is a thing, it does not matter.

Further, in this embodiment, the compression coil spring 13 of the spring probe 10 is manufactured under certain conditions, and the spring probe is used as a pressure detector according to the relationship between the spring reaction force and the amount of compression. Use
An appropriate pressing force applied to the package 1 was determined. But,
Since this spring reaction force may change depending on manufacturing conditions and the like, the data shown here is considered as an example.

Next, the operation of the test handler will be described.

First, as shown in FIG. 1A, the handler arm 9 provided with an additional pressing force sensor 14 is directly above the socket housing 8 with the package 1 held by vacuum suction on the bottom surface. And at a predetermined distance from it. This is a state in which the plurality of solder balls 4 of the package 1 and the plurality of spring probes 10 of the test handler have been transported to positions Z0 so as to face each other and stopped.

Next, as shown in FIG. 1B, the handler arm 9 is lowered at an appropriate speed from the position Z0, and the distance between the plurality of opposed solder balls 4 and the plurality of spring probes 10 is increased. Is applied with a pressing force, and these are electrically connected. The pressing force during this operation is
The pressing force sensor 14 provided on the arm 9 detects each time, and the total pressing force ΔC
p increases as the pressing force increases. This total pressure Σ
At about the same time when Cp reaches the reference pressing force, the lowering of the handler arm 9 is stopped. This handler
The stop position of the arm 9 is defined as Z1.

The test handler holds the state where the reference pressing force is applied to the package 1 and transmits a signal from the measurement board 6 of the test handler to measure the electrical characteristics of the package. evaluate. After performing this measurement, the handler arm 9 is raised from the position Z1 to the position Z0, and returned to the state shown in FIG. The package 1 is transported to the next step, and the vacuum suction of the package 1 is released. By repeating the above operation, the measurement of the electrical characteristics of the package 1 can be performed.

When the pressing force is applied to the package 1 by lowering the handler arm 9, the total pressing force Σ
FIG. 2 shows the relationship between the operating distance | Z0−Z1 | of the handler arm 9 according to the present embodiment and the horizontal axis representing the total pressing force ΔCp on the vertical axis.

As shown in FIG. 2, the thickness A of the package 1
Is larger than the standard thickness, the operating distance | Z0-Z1 | of the handler arm 9 is equal to the package 1 at x1.
Starts to increase the total pressing force Cp, and the total pressing force ΣCp reaches the reference pressing force (200 N) at x2, and the handler arm 9 stops. When the thickness A of the package 1 is smaller than the standard thickness, the operating distance | Z0-Z of the handler arm 9
1 |, the pressing force starts to be applied to the package 1 at x3, and the total pressing force ΔCp starts to rise. At x4, the total pressing force ΔCp reaches the reference pressing force, and the handler arm 9 is stopped. The operating distance of the handler arm 9 at this time is x1 <x2, x3 <x4, and x
1 <x3 and x2 <x4.

As a result, the thickness of the package becomes | x3-x
Even when the difference is only 1 |, the total pressing force ΔCp can be controlled to the reference pressing force, and it is possible to cope with products having different package thicknesses.

Although the pressing force sensor 14 is provided on the handler arm 9 for controlling the movement of the test handler, if the total pressing force ΔCp applied to the package 1 can be measured properly, the handler arm 9 Or, it may be attached to other members.

Although the embodiments have been specifically described with reference to the drawings, the present invention is not limited to the above-described embodiments, and all aspects of the present invention may be implemented without departing from the scope of the invention. Including implementation.

[0039]

As described above, according to the present invention,
The electrodes of the semiconductor package and the contactors of the test handler are always controlled to the same pressing force by controlling the handler arm, and the electrical characteristics of the semiconductor package can be measured. It is possible to measure the electrical characteristics of the semiconductor package with high reliability even if the occurrence of the problem occurs.

Further, according to the present invention, even when the thickness of the semiconductor package is greatly different, the same pressing force is always controlled without requiring the auxiliary member used due to the difference in thickness. Since the electrical characteristics of the semiconductor package can be measured with high reliability, it is possible to reduce costs such as time and maintenance of auxiliary members.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a method for measuring electrical characteristics of a semiconductor package.

FIG. 2 is a diagram in which the vertical axis represents the total pressing force, which is the output of a pressing force sensor provided on the handler arm, and the horizontal axis represents the operating distance of the handler arm.

FIG. 3 shows a configuration of a BGA package;
(A) is a top view, (B) is a side view, and (C) is a bottom view.

FIG. 4 is a schematic view showing a conventional method for measuring electrical characteristics of a semiconductor package.

FIG. 5 is a cross-sectional view of a case where a test housing constituted by a socket housing having a spring probe of a test handler, a wiring board and a measurement board is brought into contact with a solder ball of a package; is there.

FIG. 6 is a sectional view showing a spring probe as a contactor of the test handler.

FIG. 7 is a diagram illustrating a relationship when a pressing force applied between one solder ball and one spring probe is taken on a vertical axis, and a compression amount of a compression coil spring is taken on a horizontal axis. .

FIG. 8 is a diagram illustrating a relationship when a pressing force applied between one solder ball and one spring probe is taken on a vertical axis, and a contact resistance by each pressing force is taken on a horizontal axis. .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... BGA package, 2 ... Substrate, 3 ... Cap, 4 ... Solder ball, 6 ... Measurement board, 7 ... Wiring board, 8 ... Socket housing, 9 ... Handler arm, 10 ... Spring probe, 11 ... barrel, 12
... Plunger, 13 ... Compression coil spring, 14 ... Pressure sensor, L1 ... Constant distance at which handler arm operates, L2 ... Compression amount of compression coil spring, Cp ... Pressure, Rc ... Contact resistance, ΔCp ... Comprehensive pressure

Claims (3)

[Claims] 1. A plurality of contactors having a pressing force sensor and incorporated in a socket housing of a test handler for measuring electric characteristics of a semiconductor package, and a plurality of semiconductor packages attached to a handler arm of the test handler. In an electric characteristic measuring method for measuring electric characteristics of a semiconductor package by electrically connecting these electrodes by relatively pressing the electrodes, a representative one of the plurality of electrodes and a A pressing force is applied to a representative one of the plurality of contactors used as a pressure detector for determining an appropriate pressing force, and the contactors are electrically connected to each other. Sequentially measures the pressing force applied to the contactor with respect to the distance to press the contactor relatively, and the electrode for each pressing force A contact resistance, which is an electric resistance of a circuit formed by the contactor, is measured, and an electric characteristic applied between the electrode and the contactor can be measured. A first step, a second step of calculating a reference pressing force by multiplying the set pressing force by the number of the plurality of electrodes, and moving the semiconductor package by the handler arm, and A pressing force is applied between the plurality of contactors and electrically connected therebetween, and the applied total pressing force is detected by the pressing force sensor, and the reference pressing force and the total pressing force are detected. A third step of controlling the handler arm so that the two values coincide with each other, and a fourth step of measuring the electrical characteristics of the semiconductor package while maintaining the controlled overall pressing force. Measuring electric characteristics wherein the. 2. A semiconductor device comprising a measurement board, a wiring board, a plurality of contactors, and a handler arm having a pressing force sensor, wherein a semiconductor package is held by the handler arm and movement thereof is controlled. In a test handler for measuring an electrical characteristic of a semiconductor package, a test handler is provided between a representative one of the plurality of electrodes of the semiconductor package and a representative one of the plurality of contactors opposed thereto. A pressure is applied to electrically connect these, and the pressing force measures the pressing force applied to the contactor relative to a distance at which the electrode relatively presses the contactor, and the pressing force for each pressing force is measured. Measure the contact resistance, which is the electrical resistance of the circuit formed by the electrode and the contactor, and measure the contact resistance between the electrode and the contactor. First means for setting a predetermined pressing force capable of measuring applied electric characteristics and preventing the electrodes from having an appearance defect; and calculating a reference pressing force by multiplying the set pressing force by the number of the plurality of electrodes. And means for moving the semiconductor package by the handler arm, applying a pressing force between the plurality of electrodes and the plurality of contactors, and electrically connecting the plurality of contactors with the plurality of contactors. Third means for detecting a certain pressing force by the pressing force sensor and controlling the handler arm so that the reference pressing force and the total pressing force coincide with each other; A fourth means for holding and measuring the electrical characteristics of the semiconductor package. 3. The test handler according to claim 2, wherein the contactor is used as a pressure detector for determining an appropriate pressing force.