JPH07111283A - Apparatus for measuring temperature coefficient of semiconductor - Google Patents

Abstract

PURPOSE:To decrease the breakage of nits and shorten the time required for temperature adjustment when measuring the temperature coefficient of a semiconductor circuit unit formed on a wafer. CONSTITUTION:A stress absorbing heat medium 10 is provided on part of the top surface of a heating stage 6 in an apparatus for measuring the temperature coefficient of a semiconductor device comprising a heating stage 6 for setting the semiconductor wafer 3 to a predetermined measuring temperature, a bundle of probe needles 4 for taking out signals by electrically connecting it to a pad portion of each semiconductor circuit unit formed on the wafer, a positioning operation mechanism for moving and actuating the bundle of probe needles while observing the position on the pad portion with a microscope (not shown in the Figure) and a semiconductor characteristics measuring device for processing the signals from the bundle of probe needles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring temperature characteristics of semiconductor circuit units or the like formed in large numbers on a semiconductor wafer.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, after forming a large number of semiconductor circuit units, etc. on a wafer and before cutting and separating each circuit unit, the temperature characteristics of each circuit unit are measured in a wafer state in advance. Pass / fail judgment is performed.
FIG. 3 is a schematic view showing a conventional apparatus for measuring the temperature characteristic of the semiconductor circuit unit 1 formed on the semiconductor wafer 3 described above. That is, a heating stage 6 for setting a semiconductor wafer at a desired measurement temperature and a probe needle bundle for electrically connecting to a pad portion of each semiconductor circuit unit 1 formed on the wafer 3 to take out a signal or the like. 4, a positioning operation mechanism 7 for operating and adjusting the relative position with respect to the probe needle bundle while observing the position of the pad portion under a microscope (not shown), and semiconductor characteristics for processing signals from the probe needle bundle. It is a semiconductor temperature characteristic measuring device having a measuring device 8. FIG. 4 is an enlarged view showing a state where the probe needle bundle is brought into contact with one of the semiconductor circuit units shown in FIG. After the semiconductor wafer 3 is heated to a predetermined temperature, an electric signal is input through the probe needle bundle 4, a corresponding electric signal is output, and this is analyzed by the semiconductor characteristic measuring instrument 8 to determine the wafer state at a specific temperature. The temperature characteristics of each semiconductor circuit unit are checked.

[0003]

In such a conventional method, as shown in FIG. 5 (a), pressure is applied so that the tips of the needles of the probe needle bundle 4 contact at the center of the pad 2 at room temperature. Can be installed. When the wafer in this state is heated to a high temperature, the probe needle bundle 4 expands in the direction of arrow 41, so that the contact position between the probe needle bundle 4 and the pad 2 changes as shown in FIG. There is a problem that a part of the passivation film 5 covering the above is destroyed, and defects frequently occur in the subsequent wire bonding process. Further, there is a problem that the probe needle bundle is damaged. Further, in order to avoid such a problem, when the probe needle bundle is brought as close as possible to the wafer in a non-contact state and the temperature is raised to the same measurement temperature as the wafer temperature before measurement,
It was necessary to wait for one measurement temperature for about 1 hour, and a long waiting time was required for measurement. SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor temperature characteristic measuring device that solves such a problem that occurs when changing a measured temperature.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a heating stage for setting a semiconductor wafer to a desired measurement temperature and a pad portion of each semiconductor circuit unit on the wafer are electrically connected to input a signal. A probe needle bundle for outputting, a positioning operation mechanism for moving and operating the probe needle bundle or the heating stage while observing the position of the pad portion under a microscope, and semiconductor characteristics for processing signals from the probe needle bundle In a semiconductor temperature characteristic measuring device having a measuring instrument, a stress absorbing heat medium provided on the heating stage for promptly moving the tip of the probe needle bundle to the temperature is provided. That is, according to the present invention, a stress absorbing heat medium is provided on the heating stage, and the tip of the probe needle bundle is brought into contact with the heat absorbing medium, so that the temperature is changed by contacting with the pad of the conventional semiconductor circuit unit. It is intended to provide a means capable of avoiding damage to a pad and quickly reaching a desired measured temperature.

Further, as shown in FIG. 1 (a), the present stress absorbing heat medium is composed of, for example, two plates and a structure excellent in heat conductivity in which a spring is coupled between the two plates. It is possible to avoid the damage of the probe needle by transmitting the heat from the probe needle bundle to the probe needle bundle in an extremely short time and absorbing the stress generated by the expansion and contraction accompanying the temperature change of the probe needle.

[0006]

[Function] A flat stress absorbing heat medium is provided on the heating stage of the semiconductor temperature characteristic measuring device set to the measurement temperature,
Since the tip of the probe needle is brought into contact with this to raise the temperature, the semiconductor circuit unit formed on the wafer is not damaged as compared with the conventional method of changing the temperature in the state of being in contact with the pad. Further, even if the probe needle bundle expands and a stress is generated between the probe needle bundle and the main heating medium when the set temperature is raised, the stress is absorbed by the heating medium, so that the probe needle bundle is not damaged. . In addition, compared to the conventional method of changing the temperature of the probe needle in the non-contact state, it is possible to change to the desired measurement temperature in an extremely short time. Therefore, when measuring at a large number of preset temperatures, the waiting time for measurement can be significantly reduced, and efficient measurement is possible.

[0007]

【Example】

(Embodiment 1) As shown in FIG. 3, a heating stage 6 having a Nichrome Joule heating element in a stainless steel hollow plate having a length of 10 cm, a width of 30 cm, and a thickness of 3 cm, and a pad portion of each semiconductor circuit unit on a wafer. A probe needle bundle 4 for electrically connecting and inputting / outputting a signal, and a not shown 10
A semiconductor temperature measuring device including a positioning operation mechanism 7 for finely adjusting the position of the probe needle bundle in a three-dimensional direction under a 0 × optical microscope and a semiconductor characteristic measuring instrument 8 for measuring and processing a signal from the probe needle bundle. In the measuring device, a device having the stress absorbing heat medium 10 shown in FIG. 1A was provided at one end of the upper surface of the heating stage 6.

As the plate material for the stress absorbing heat medium of this embodiment, graphite, industrial diamond, gold, stainless steel or the like, which has excellent thermal conductivity, can be used. As the spring material, carbon fiber with excellent thermal conductivity and elasticity,
Gold, copper, stainless steel, etc. are possible. In this embodiment,
0.5cm long, 0.5cm wide, and thickness 0.1c
As the spring material, a stress-absorbing heat medium having a structure in which five m carbon fibers having a diameter of 0.1 mm and a coil diameter of 1.0 mm were bonded together was used as a spring material. First of all, the measurement is performed on the other part on the heating stage 6 of the present semiconductor temperature characteristic measuring apparatus, including 2000 semiconductor circuit units 1 having 8 pads for each unit, and a measurement object having a diameter of 3 inches and a thickness of 450 μm. The semiconductor wafer 3 to be mounted was placed, and the circuit characteristics of all the units were measured at room temperature. Next, in order to measure the measurement temperature at 100 ° C., the heating stage was set at 100 ° C., and while observing under a microscope, the tip of the probe needle bundle in which 8 needles were set on the stress absorbing heat medium was brought into contact. Let Since the temperature of the tip of each needle of the probe needle bundle reached 100 ° C. in about 10 minutes which is about 1/10 of the time of the conventional method, the probe needle bundle 4 is measured by the positioning operation mechanism 7. Each needle corresponding to the center of each of the eight pads of one circuit unit of the semiconductor wafer 3 was brought into contact. After that, the temperature characteristic of 2000 circuit units was automatically measured in 7 hours by this positioning operation mechanism. After the measurement was completed, all passivation films around the pads were inspected with a microscope, but no damage or damage was found.

(Embodiment 2) In Embodiment 1, as shown in FIG. 1 (b), the diamond plate on the upper part of the stress absorbing heat medium has a conical shape having a side surface having an inclination similar to that of the probe needle bundle. Of the probe needle bundle was made to come into contact with a wide area of the probe needle bundle. The stress generated between the concave surface and the conical surface of the recess due to the expansion of the probe needle due to the temperature change was easily relieved by the conical surface. In this case, it took 4 minutes for the tip of each needle of the probe needle bundle to reach 100 ° C. Other than this, the same results as in Example 1 were obtained.

(Embodiment 3) The stress absorbing heat medium on the heating stage of the semiconductor temperature characteristic measuring apparatus of Embodiment 1 is as shown in FIG.
An example in the case of two stainless plates and metal wool shown in (c) is shown. As a metal wool material,
Examples include gold, copper, and stainless steel, which have excellent thermal conductivity. In this example, a stainless steel wool of 1 gram was sandwiched between two stainless steel plates of the same size as the stress absorbing heat medium of Example 1 and joined to the stainless steel plate. In this case, the tip of each needle of the probe needle bundle is 1
It took 7 minutes to reach 00 ° C. Other than this, the same results as in Example 1 were obtained.

(Embodiment 4) An embodiment in which the heating medium of the heating stage of the semiconductor temperature characteristic measuring apparatus of Embodiment 1 is a diamond powder bed will be described. Examples of the powder material include graphite having excellent thermal conductivity, industrial diamond, gold and stainless steel. In this example, the stress absorbing heat medium of Example 1 was replaced by 2 cm in length, 2 cm in width, and 1 cm in thickness.
A recess having a depth of 0.5 cm and a depth of 0.5 cm was provided, and 2.0 g of stainless powder having a diameter of 10 ηm to 100 ηm was stored therein. A cross-sectional view of the stress absorbing heat medium is shown in FIG.
It shows in (d). In this case, it took 5 minutes for the tip of each needle of the probe needle bundle to reach 100 ° C. Other than this,
The same result as in Example 1 was obtained.

[0012]

When the temperature characteristic of the semiconductor circuit unit formed on the wafer is measured by the semiconductor temperature characteristic measuring apparatus of the present invention, damage to the unit can be significantly reduced. Further, the time required for temperature adjustment can be extremely shortened.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a stress absorbing heat medium according to the present invention.

FIG. 2 is a schematic diagram showing a state in which the temperature of a probe needle bundle is adjusted using the semiconductor temperature characteristic measuring apparatus according to the present invention.

FIG. 3 is a schematic diagram for explaining a conventional example.

FIG. 4 is a schematic view showing a relationship between a probe needle bundle and a pad of a semiconductor circuit unit in a conventional example.

5A and 5B are views for explaining the operation of a conventional example, FIG. 5A shows a state at room temperature, and FIG. 5B shows a state at high temperature.

[Explanation of symbols]

1: Semiconductor circuit unit on semiconductor wafer 2: Pad of semiconductor circuit unit 3: Semiconductor wafer 4: Probe needle bundle 41: Moving direction of contact point between probe needle bundle and pad on wafer at temperature rise 5: Passivation film 6: Heating stage 7: Positioning operation mechanism 8: Semiconductor characteristic measuring instrument 10: Stress absorption heat medium

Claims (5)

[Claims] 1. A heating stage for setting a semiconductor wafer to a desired measurement temperature, and a probe needle bundle for electrically connecting to a pad portion of each semiconductor circuit unit formed on the wafer to take out a signal. A semiconductor temperature characteristic having a positioning operation mechanism for moving and adjusting the relative position of the pad portion and the probe needle bundle while observing under a microscope, and a semiconductor characteristic measuring device for processing a signal from the probe needle bundle. In the measuring device, a semiconductor temperature characteristic measuring device having a stress absorbing heat medium located on the heating stage for promptly shifting the tip of the probe needle bundle to the measuring temperature. 2. The stress absorbing heat medium has a structure in which two plates are connected to each other by a spring, and the plates are made of graphite.
2. The semiconductor temperature characteristic measuring device according to claim 1, wherein the spring material is made of industrial diamond or metal, and the spring material is made of carbon fiber or metal. 3. A conical recess is provided on the upper surface of the upper plate of the stress absorbing heat medium, and the inclination of the side surface of the recess is about the same as the inclination of the probe needle bundle. The semiconductor temperature characteristic measuring device according to. 4. The semiconductor temperature characteristic measuring device according to claim 2, wherein the stress absorbing heat medium comprises two plates and metal wool inserted between them. 5. The semiconductor temperature characteristic measuring device according to claim 1, wherein the stress absorbing heat medium comprises a metal powder bed, a graphite powder bed, or a diamond powder bed.