JP2001349926A - Measuring jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring jig with a long service life capable of reproducibly and highly accurately detecting the electric characteristic of a semiconductor element. SOLUTION: This measuring jig measures the electric characteristic of a semiconductor element 16 having a grounding surface on the bottom surface of a package 17 of a body to be measured 20 in which the semiconductor device 16 is integrated in the package 17. The measuring jig comprises at least mounting means 1 and 1 for mounting the body to be measured 20, a voltage applying means 4 for receiving the body 20 to be measured and applying a grounding voltage to the semiconductor device 16, and connecting means 11 and 11 for transmitting an input signal to the semiconductor device 16 and receiving an output signal from the semiconductor device 16. A conductive film 7 is interposed between the grounding surface of the bottom surface of the package 17 and the grounding surface of the measuring jig, and the bottom surface of the package 17 is brought into contact with the grounding surface of the measuring jig by surface to provide electrical connection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring jig for measuring electrical characteristics of high-frequency elements and components.

[0002]

2. Description of the Related Art In recent years, the spread of portable radio telephones has been remarkable worldwide, and the development of high-frequency power amplifier elements, which are the key components thereof, has been actively pursued. I have. FIG. 4 shows a high-frequency power amplifier element (measurement object 2) used in the portable radio telephone or the like.
0), and FIG. 5 shows the back surface thereof.

The semiconductor element 16 is bonded to the die area 15b of the lead frame with silver paste or the like, and is electrically connected to each of the lead frame parts 15a and 15b from each electrode pad on the chip surface via gold wires 19a and 19b. It is connected to the. Among the terminals on the semiconductor element 16, the RF signal terminal and the DC bias terminal are connected to the side surface lead portion 15a of the lead frame. On the other hand, the ground terminal of the semiconductor element 16 has a wire layout connected to the die area 15b.

The lower surface of the die area 15b is
Resin mold package (hereinafter referred to as package) 17
Are exposed to the outside so as to be flush with the lower surface of the. That is, the die area portion 15b also functions as a heat sink for transmitting heat generated by the ground electrode and the semiconductor element 16 to the outside. In a high-frequency circuit, a slight grounding inductance of a bonding wire or a lead frame acts as a feedback circuit, causing deterioration of the performance of the element or unnecessary oscillation. And the heat generated in the transistor portion in the chip can be efficiently released to the outside.

From a similar point of view, a measuring jig used for measuring the electrical characteristics of a high-frequency element having such a mounting structure has a ground inductance generated when conducting from the element as small as possible. There is a demand for low heat resistance and good heat dissipation. Otherwise, the parasitic inductance of the measuring jig and the poor heat radiation cause a decrease in gain and the like, and the inherent performance of the element cannot be taken out to the outside.

FIG. 6 shows the structure of a conventional measuring jig. To explain the structure, reference numeral 10 denotes a portion serving as a pedestal of a jig, which is made of metal such as aluminum or brass, serves as a reference for a ground potential of a measurement system, and absorbs heat generated from a measured object. Also serves as a heat sink.

On the pedestal 10 is mounted a printed circuit board 4 on which a wiring pattern corresponding to the dimensions of the terminals of the device under test 20 is printed. The metallized patterns 8a and 8b at the center of the printed circuit board 4 come into contact with the lead terminals 15a of the DUT 20 and the exposed portion of the back surface of the die area (hereinafter referred to as a slag or a grounded back terminal) 15b to provide electrical continuity. Then, the input / output signal lines and bias lines are guided to the respective coaxial adapters 11 attached to the side surfaces of the pedestal 10 via the respective metallization patterns 8a on the printed circuit board 4.

On the other hand, the slug 15 b of the measured object 20 comes into contact with the ground pattern 8 b of the printed circuit board 4. The ground pattern 8b has a through hole 18 and is grounded by being electrically connected to the entire metallization pattern on the back surface of the substrate.

The measured object 20 is fixed to a measuring jig by an element holding head 14. Thereby, the slug 15b of the measured object 20 and the metallized pattern (wiring pattern) 8b of the printed circuit board 4 come into contact with each other and are electrically connected.

The lead terminal 15a of the device under test 20
However, the elasticity is given to the printed circuit board 4 through a spring (spring) 9 by a resin lead pressing pin 13.
It contacts and is electrically connected to the upper metallization pattern (ground pattern) 8a.

Reference numeral 12 denotes a side plate of the measuring jig. The coaxial adapter 11 is fixed to the side plate 12 by a fixing screw 2. In FIG. 6, the bonding wires in the measured object 20 are omitted.

FIG. 7 is a plan view of a printed circuit board 4 used in a conventional measuring jig. A metallized pattern 5 is printed on the substrate 4, and a metallized pattern 8 a near the center of the substrate comes into contact with a lead terminal 15 a (see FIG. 4) led out from a side surface of the device 20, while the center of the substrate 4 Through hole 1 in the ground pattern 8b
8 is formed, and comes into contact with a slag 15 b which is a ground terminal of the measured object 20.

[0013]

In the conventional measuring jig, the ground terminal of the DUT 20 and the slag 15b serving as a heat sink are connected to the ground pattern 8 on the upper surface of the printed circuit board 4.
a and is electrically connected to a ground plane, which is a metallized pattern on the entire back surface, through the through hole 18. However, at this time, there were the following problems.

In order to obtain good electric characteristics, the grounding inductance during conduction is minimized while the device under test 20 is mounted on the measuring jig, and the heat generated from the element is reduced to the jig side as much as possible. It is necessary to suppress the characteristic deterioration and thermal runaway due to the self-heating of the element after taking out.

In the above conventional example, the element lower surface having the slug portion having the function of a heat sink and the ground terminal is in direct contact with the non-elastic printed board 4, but the element lower surface has a warp (warp). ) And resin burrs often occur,
Also, a slight step may occur between the resin portion of the package and the slag.

On the other hand, the flatness of the contact surface is also poor on the printed circuit board 4 side due to unevenness of plating on the metallized pattern surface in addition to the unevenness of the substrate itself. Has a smaller effective contact area. Therefore, conduction ground inductance and thermal resistance increase.

Therefore, when the measurement of the device under test 20 is performed using a conventional jig, the characteristics of the device itself cannot be derived, and the gain and VSWR (standing wave ratio, voltage stabilization ratio) cannot be obtained.
High-frequency characteristics such as anding wave ratio) are lower in gain than actual device characteristics and higher in VSWR, and in the worst case, oscillate.

Further, since the lower surface of the element is directly pressed against the printed board 4 having low elasticity, the effective contact area and the contact area slightly change each time due to the load due to the pressing. There is a disadvantage that the reproducibility of the measurement is poor due to the variation of the flow path of the flow. In addition, since there is no mechanism for absorbing the load and impact at the time of attachment / detachment, there is a problem that the terminal contact portion of the printed circuit board 4 is severely worn and the life of the measuring jig is extremely short.

Further, the printed board 4 is usually made of a ceramic such as glass epoxy resin or alumina. However, these have low thermal conductivity, and it is not sufficient to dissipate heat only from the through holes 18 provided in the board. However, there was also a problem that the heat resistance was high.

The present invention has been made in view of the above circumstances, and provides a measuring jig capable of detecting the electrical characteristics of a semiconductor element with good reproducibility and high accuracy and having a long life. The purpose is to provide.

[0021]

In order to achieve the above-mentioned object, the present invention is configured as follows.

(1) At least the device to be measured is mounted to measure the electrical characteristics of the semiconductor device having a ground plane on the package bottom surface of the device to be measured in which the semiconductor device is integrated in a package. Mounting means for receiving the object to be measured, voltage applying means for applying a ground voltage to the semiconductor element, and connecting means for transmitting and receiving an input signal to the semiconductor element and an output signal from the semiconductor element. In the measuring jig having, a conductive film is interposed between the grounding surface of the package bottom and the grounding surface of the measuring jig, and the package bottom and the grounding surface of the measuring jig are brought into surface contact. In this case, the electrical connection is obtained.

According to this configuration, a contact pressure is applied to the measured object via the conductive film, and the ground surface on the back surface of the package is
Since the measurement jig is brought into contact with the ground surface, a large surface contact portion can be ensured, and the contact state is stabilized. Therefore, the flatness of the contact surface due to warpage and resin burrs generated on the back of the package, steps from the ground surface on the back of the package, warpage and unevenness on the printed circuit board side, and unevenness due to variations in plating of the metallized pattern, etc. Even when damaged, a stable and good electrical contact state can be obtained. Further, heat generated from the semiconductor element can be effectively absorbed (heat dissipation effect) by the conductive film. Therefore, a highly accurate ground potential can be obtained with good reproducibility.

In addition, since the impact due to the load when the contact pressure is applied is buffered by the conductive film, the wear and deformation of the voltage applying means (terminal connection portion) are reduced, and the durability (life) of the measuring jig is reduced. Dramatically improved.

(2) The base of the conductive film is fixed to a ground plane of the measuring jig.

According to this configuration, since the shortest current path is fixedly formed to the ground plane of the measuring jig via the conductive film, the current path is stabilized, and the current path is always changed. Also, good electrical contact can be reproduced in the same state, and a stable good ground potential can be obtained. (3) The conductive film has a spring property.

According to this structure, the spring property of the conductive film makes it possible to effectively buffer the impact when a contact pressure is applied to the object to be measured, and to secure a wider surface contact portion. And the stability of the electrical contact state is further improved.

Further, since the shock at the time of the contact pressure is buffered, the wear and deformation of the voltage applying means (terminal connection portion) are reduced, and the durability (life) of the measuring jig is remarkably improved.

(4) The conductive film is a phosphor bronze film.

According to this configuration, by using the phosphor bronze film having a high spring property, it is possible to effectively buffer the impact when a contact pressure is applied to the object to be measured.
A wider surface contact portion can be ensured, and the electrical contact state is more stably improved.

Further, since the shock is buffered, wear and deformation of the voltage applying means (terminal connection portion) are reduced, and the durability (life) of the measuring jig is remarkably improved.

(5) The conductive film has a thickness of 0.1.
It is characterized in that it is between 0.05 mm and 0.2 mm.

According to this configuration, since the thickness of the conductive film is set to 0.05 mm to 0.2 mm, an appropriate shock buffering action can be obtained, and the ground inductance at the time of conduction can be minimized. Further, heat generated from the measured object can be sufficiently absorbed (radiation effect). If the thickness of the conductive film is less than 0.05 mm, a sufficient shock buffering effect cannot be obtained, and heat radiation from the measured object cannot be sufficiently absorbed. On the other hand, 0.2 mm
When the value exceeds, the film strength becomes larger than the inductance, and abrasion due to stress concentration on a part due to an increase in bending moment becomes a problem.

(6) Among the grounding surfaces of the measuring jig, a grounding portion of the measuring jig for electrically connecting to a grounding surface of the bottom of the package via the conductive film has a lower portion. A slide mechanism having a spring for urging the grounding portion toward the grounding surface side of the package is provided, and a regulating mechanism for regulating an amount of protrusion of the grounding portion when the semiconductor element is not mounted is provided. Features.

According to this configuration, since the contact pressure is applied to the object to be measured via the conductive film by the slide mechanism having the spring, the surface contact portion can be further secured stably, and the electrical contact can be secured. The state is more stably improved, and the reproducibility is further improved.

Further, by a slide mechanism having a spring,
The impact caused by the load when the contact pressure is applied is more effectively buffered by the cooperative action with the conductive film, so that the abrasion and deformation of the voltage applying means (terminal connection portion) are further reduced, and the measuring jig is used. Durability (lifetime) is further improved.

[0037]

1 to 3 show an example of a measuring jig according to an embodiment of the present invention. 1 is a plan view of the measuring jig when not measuring, FIG. 2 is a cross-sectional view taken along the line XX of FIG. 1, and FIG. 3 is a cross-sectional view corresponding to the line XX of FIG.
In these figures, reference numeral 10 denotes a pedestal made of aluminum, brass, or the like, and a central portion thereof is a hollow 10 which is hollowed out in a columnar shape.
1 is provided. The hollow 101
A push-up pin 6 formed in a shape substantially matching the shape of the concave portion 101 is vertically movably fitted therein.
At the upper part of the push-up pin 6, a projecting portion 61 projecting in a convex column shape is formed.

The above-mentioned substantially matched shape means that even if the push-up pin 6 and the pedestal 10 repeatedly slide relative to each other, they are sufficiently low in terms of high frequency and mutually electrically stable with stable impedance and inductance values. This means that the push-up pin 6 and the hollowed-out recess 101 are formed so as to maintain a connected state of contact and stable heat dissipation. The push-up pin 6 and the hollow 101 form a slide mechanism.

A spring (spring) 9 is interposed between the bottom of the push-up pin 6 and the bottom of the hollow 101 of the pedestal 10, and the vertically movable push-up pin 6 resiliently moves upward. Has been energized. The push-up pin 6
May be made of metal, and may be the same material as the base 10.

In the present embodiment, the shape of the hollowed-out recess 101 and the push-up pin 6 is formed in a columnar shape having a rectangular cross section with rounded corners, and the bottom surface is flat. The present invention is not limited to this, and any shape may be used as long as the push-up pin 6 moves up and down and slides smoothly without horizontal blurring.

On the pedestal 10, a printed board 4, which is a voltage applying means, an abutting spacer 3 formed to the same thickness as the board 4, and a semiconductor element 16 are integrated in a package 17. Object 20 to be measured (see FIG. 4)
And guides 1, 1 as mounting means for positioning the metal film 7 as a conductive film, and a concave portion 1 formed inside the guides 1, 1
The two sides of (the package 17 of) the measured object 20 are sandwiched in the fitted state between a and 1a, and the measured object 20 is securely positioned.

The surface (back surface) of the printed circuit board 4 in contact with the pedestal 10 is entirely metallized to come into contact with the pedestal 10 and to make electrical connection with the lead terminals of the device under test 20.
Metallized terminal 8 of almost the same shape as the lead terminal
a and a metallized wiring 5 extending therefrom.

The tip of the metallized wiring 5 is connected to a coaxial adapter 11 attached to a side plate 12 of a measuring jig by a fixing screw 2.
, An input signal to the device under test 20 and an output signal from the device under test 20 are connected to the outside (power supply and detector).

Although every other one of the metallized terminals 8a in FIG. 1 is connected to the metallized wiring 5, terminals without the metallized wiring 5 are generally connected to a high-frequency element.
Since a grounding lead terminal for reducing noise between adjacent signal terminals is connected, these terminals without metallized wiring 5 are connected to the entire metallized surface on the back surface of the printed circuit board 4 via through holes 18. do it.

The printed circuit board 4 has a cut-out portion having a width W which is equal to or slightly wider than the width of the side where the lead terminals of the measured object 20 are located. In FIG. 1, the L
The description of the direction is omitted. Note that the printed circuit board 4 is not a hollow shape, but two boards (not shown, but arranged at positions indicated by arrows 4 and 41 in FIG. 1) provided with a width W. There may be.

The butting spacer 3 has a concave shape in a plan view, and the concave portion 31 is smaller than the shape of the push-up pin 6 and the convex portion 6 above the push-up pin 6.
It has a shape larger than one. The base of the butting spacer 3 is fixed to one side of the measured object 20 where there is no lead terminal.

As shown in FIG. 2, when the object to be measured is not mounted on the measuring jig, the upper surface of the protrusion 61 of the push-up pin 6 Although it is urged to project slightly higher than the surface of the printed circuit board 4, the projecting spacer 3 restricts the projecting, so that a constant height is always maintained. In the present embodiment, the upper part (projection 61) of the push-up pin 6 is 0.2 m from the surface of the printed board 4.
It is set to protrude by about m to 0.3 mm.

As shown in FIG. 2, the tip of the metal film 7 is formed in a rectangular convex shape slightly smaller than the concave concave portion 31 of the abutting spacer 3, and the convex portion 61 of the push-up pin 6 is formed. (Shown by a broken line), and is mounted thereon so as to cover the convex portion 61. The base formed so as to spread out from the front end thereof is arranged on the side (right) opposite to the side (left) to which the abutting spacer 3 is fixed, and the back surface of the printed circuit board 4 and the base 10 are arranged. It is sandwiched between and fixed.

Then, the metal film 7, the butting spacer 3 and the printed board 4 are covered with the left and right guides 1, 1 from above, and the fixing screws 2,
At 21, it is fixed to the pedestal 10. Note that one fixing screw 2
The base of the butting spacer 3 and the printed circuit board 4
Is fixed to the guide 1, and the base of the metal film 7 and the printed circuit board 4 are fixed to the guide 1 by the other fixing screw 21.

The metal film 7 is made of a material having conductivity and spring property (elasticity).
For example, a polyimide film laminated with a metal foil such as phosphor bronze, nickel, stainless steel, spring steel, or copper can be used.

In this embodiment, a phosphor bronze film having a high spring property is used. Further, the film thickness can be preferably set to, for example, 0.1 mm, but may be set appropriately in the range of about 0.05 to 0.2 mm. By setting the thickness to this level, an appropriate shock buffering action can be obtained, the grounding inductance during conduction can be minimized, and the heat generated from the measured object can be sufficiently absorbed (heat dissipation effect). Can be. The metal film 7 including the protruding tip portion is designed as wide as possible (with its base portion) in order to reduce the inductance component as much as possible and to improve the heat radiation. Is preferred.

FIG. 3 is a sectional view when the measured object 20 is mounted on a measuring jig. When the device under test 20 is mounted, the push-up pin 6 is lowered to the same height as the upper surface of the abutment spacer 3 by the downward bias from the element holding head 14, so that the impact is reduced and the spring 9
, A constant contact pressure is applied to the contact with the element back surface ground terminal. The metal film 7 having the above-mentioned spring property is interposed between the push-up pin 6 and the slag 15b.
5b can be stably obtained in a wide surface contact state.

Since the base of the metal film 7 is sandwiched between the printed circuit board 4 and the pedestal 10, the metal film 7 is connected to the reference ground potential of the pedestal 10 via the shortest path, and the output signal from the ground terminal of the semiconductor element 16 is taken out. The resulting parasitic inductance is very small. This makes it possible to accurately detect the electrical characteristics of the high-frequency element.

The heat generated during the operation of the element is transmitted to the pedestal 10 via the base of the metal film 7, while
Since the light is transmitted from the metal film 7 to the pedestal 10 via the push-up pin 6 via the shortest path, the heat radiation effect is also very good due to the synergistic effect.

As for the durability, it has been confirmed from the experimental results that the initial measured value can be reproduced and maintained without replacing the contact portion more than 300,000 times, and that a level enough to withstand mass production is ensured. Was completed.

In this embodiment, when applied to the measurement of a high-frequency element, the characteristic that the ground inductance is reduced is obtained. However, the present invention is not limited to the high-frequency element but is widely applied to the measurement of general semiconductor elements. Thus, good heat dissipation, durability, and reproducibility of contact can be obtained.

[0057]

(1) Since a conductive film is interposed between the grounding surface of the package bottom and the grounding surface of the measuring jig, a large surface contact portion can be ensured, and The contact state is stabilized, and warpage and resin burrs generated on the back of the package, steps from the ground plane on the back of the package, warpage and unevenness on the printed circuit board side, and unevenness due to unevenness in plating of the metalized pattern, etc. Even when the flatness of the surface is impaired, a stable and good electrical contact state can be obtained.

Further, heat generated from the object to be measured can be effectively absorbed (heat radiation effect) by the conductive film.

Therefore, it is possible to minimize the grounding inductance during conduction as much as possible and to suppress the deterioration of the characteristics and the thermal runaway due to the self-heating of the measured object, and to always obtain a highly accurate grounding potential with good reproducibility. This is particularly suitable when measuring high frequency devices.

The impact caused by the load when the contact pressure is applied is
Since the buffer is provided by the conductive film, the abrasion and deformation of the voltage applying means (terminal connection portion) are reduced, and the durability (life) of the measuring jig is remarkably improved.

(2) Since a part of the conductive film is fixed to the ground plane of the measuring jig, the shortest current path to the ground plane of the measuring jig via the conductive film is fixed. As a result, the current path is stabilized, good electrical contact can always be reproduced in the same state (even when the object to be measured is replaced), and a stable good ground potential can be obtained.

(3) Since the conductive film has a spring property, an impact when a contact pressure is applied to the object to be measured can be effectively buffered, and a surface contact portion can be secured more widely. And the stability of the electrical contact state is further improved.

Further, since the shock at the time of the contact pressure is effectively buffered, the wear and deformation of the voltage applying means (terminal connection portion) are reduced, and the durability (life) of the measuring jig is further improved.

(4) Since the conductive film is a phosphor bronze film, it is possible to effectively buffer the impact when a contact pressure is applied to the object to be measured, and to secure a wider surface contact portion. And a stable electrical contact state can be obtained.

Further, since the shock at the time of contact pressure is effectively buffered, wear and deformation of the voltage applying means (terminal connection portion) are reduced, and the durability (life) of the measuring jig is reliably improved. Can be.

(5) The thickness of the conductive film is set to 0.
Since the thickness is set to 0.05 mm to 0.2 mm, a sufficient shock buffering action can be obtained, and the ground inductance during conduction can be minimized.

(6) Since a slide mechanism having a spring is provided and a contact pressure is applied through the conductive film, the surface contact portion can be further stably secured.
The electrical contact state is more stably improved, and the reproducibility is further improved. In particular, the characteristic evaluation can be performed with the parasitic inductance that greatly affects the characteristics of the high-frequency element always kept very small, which is more suitable for the measurement of the high-frequency element.

Further, by a slide mechanism having a spring,
Since the impact due to the load at the time of applying the contact pressure is effectively buffered by the cooperative action with the conductive film, the abrasion and deformation of the voltage applying means (terminal connection portion) are further reduced, and the measurement jig of the measuring jig is reduced. The durability (lifetime) is further improved.

The heat radiation effect of the conductive film makes it possible to suppress the deterioration of the characteristics and the thermal runaway due to the self-heating of the measured object, and to always obtain a highly accurate ground potential with good reproducibility.

Therefore, in addition to the remarkable improvement in the reliability and durability of the measuring jig, the electrical characteristics of the device to be measured are not modulated, so that the device is suitable for an inspection process in a mass production line of measuring elements. Become.

Furthermore, when the semiconductor element is not mounted, the protrusion of the grounding portion is regulated by the regulating mechanism, so that the maintenance of the measuring jig when not in use is ensured.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a measuring jig according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a cross-sectional view when the device is mounted.

FIG. 4 is a cross-sectional view illustrating a mounting structure of a device to be measured.

FIG. 5 is a bottom view of the same.

FIG. 6 is a cross-sectional view showing an example of a conventional measurement jig when an element is mounted.

FIG. 7 is a plan view of the printed circuit board.

[Explanation of symbols]

 1-Mounting means 3-Regulating means 4-Voltage applying means 6-Slide mechanism 7-Conductive film 11-Connecting means 16-Semiconductor element 17-Package 20-Measurement object 101-Slide mechanism

Claims (6)

[Claims] At least the device to be measured is mounted in order to measure an electrical characteristic of the semiconductor device having a ground plane on a bottom surface of the package of the device to be measured in which the semiconductor device is integrated in a package. It has mounting means, voltage applying means for receiving the device under test and applying a ground voltage to the semiconductor element, and connecting means for transmitting and receiving an input signal to the semiconductor element and an output signal from the semiconductor element. In the measuring jig, a conductive film is interposed between the grounding surface of the package bottom and the grounding surface of the measuring jig, and the package bottom is brought into surface contact with the grounding surface of the measuring jig. A measuring jig characterized by obtaining an electrical connection. 2. The measuring jig according to claim 1, wherein a base of the conductive film is fixed to a ground plane of the measuring jig. 3. The measuring jig according to claim 1, wherein the conductive film has a spring property. 4. The measuring jig according to claim 1, wherein the conductive film is a phosphor bronze film. 5. The conductive film has a thickness of 0.05.
The measuring jig according to any one of claims 1 to 4, wherein the measuring jig has a diameter of 0.2 to 0.2 mm. 6. A grounding portion of the measuring jig for electrically connecting to a grounding surface of the bottom of the package via the conductive film among grounding surfaces of the measuring jig, a spring is provided at a lower portion. A slide mechanism for urging the ground portion toward the ground surface of the package, and a regulating mechanism for regulating the amount of protrusion of the ground portion when the semiconductor element is not mounted is provided. The measuring jig according to claim 1.