JP2014190801A - Semiconductor device temperature controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a temperature of a semiconductor device as a test object accurately.SOLUTION: A semiconductor device temperature controller (10A) which controls a heat source (20A) to set a desired temperature of a semiconductor device formed on a semiconductor wafer (30) as a test object comprises: a probe (11) configured to be able to contact a temperature measurement device (31) formed on the semiconductor wafer; an electric characteristics measurement unit (12) measuring the electric characteristics of the temperature measurement device via the probe with the semiconductor wafer being heated by the heat source or being cooled; a heat source control unit (16A) receiving a measurement result obtained by the electric characteristics measurement unit and a target value, and controlling the heat source so as to cause the measurement result obtained by the electric characteristics measurement unit to coincide with the target value. The target value is determined based on a measurement result of the electric characteristics of a temperature measurement device (31') formed on a reference semiconductor wafer (30') placed in a thermostat bath (40) whose temperature is maintained in a desired temperature.

Description

  The present invention relates to a temperature control device for a semiconductor device, and more particularly to a semiconductor device temperature control device for setting a semiconductor device formed on a semiconductor wafer to a desired temperature.

  A semiconductor device may be inspected at the wafer level before packaging the semiconductor device. Conventionally, when inspecting temperature characteristics of a semiconductor device at a wafer level, the semiconductor wafer is fixed by a chuck, and the entire semiconductor wafer is heated or cooled to a desired temperature by a heat source inside the chuck (for example, see Patent Document 1). reference).

JP 2007-201484 A

  When a semiconductor wafer is heated or cooled via a chuck while exposed to a room temperature environment, heat is absorbed and released from the surface of the semiconductor wafer to the open space, so the temperature of the semiconductor device formed on the semiconductor wafer is accurately controlled. Is difficult.

  Although it is conceivable to measure the temperature of a semiconductor device with a contact-type temperature sensor, a temperature difference occurs at the contact point between the device and the sensor due to heat escaping through the sensor, so it is possible to know the temperature of the semiconductor device accurately. Have difficulty.

  Further, it is conceivable to use a non-contact type temperature sensor such as a radiation thermometer, but these generally have a problem that the measurement accuracy is low. Also, because it is necessary to apply black body paint to the object to be measured for temperature measurement, it is necessary to prepare a reference device instead of the device to be inspected and measure its temperature. I don't know the exact temperature.

  In view of the above problems, an object of the present invention is to accurately control the temperature of a semiconductor device to be inspected.

  A semiconductor device temperature control apparatus according to an aspect of the present invention is a semiconductor device temperature control apparatus that controls a heat source to set a semiconductor device formed on a semiconductor wafer to be inspected to a desired temperature. A probe configured to be able to contact a temperature measuring device formed on the wafer, and measuring the electrical characteristics of the temperature measuring device through the probe in a state where the semiconductor wafer is heated or cooled by the heat source. And a heat source control unit that receives the measurement result and the target value by the electric characteristic measurement unit and controls the heat source so that the measurement result by the electric characteristic measurement unit matches the target value. The target value is an electrical characteristic of a temperature measuring device formed on a reference semiconductor wafer placed in a thermostatic chamber maintained at the desired temperature. It is to be determined on the basis of the measurement results.

  According to this, the heat source is controlled so that the electrical characteristics of the semiconductor device to be inspected are the same as the measurement results of the electrical characteristics of the temperature measuring device formed on the reference semiconductor wafer placed in the thermostat. The Therefore, the temperature of the semiconductor device formed on the semiconductor wafer to be inspected can be controlled with high accuracy equivalent to the set temperature of the thermostat.

  The semiconductor device temperature control apparatus may further include another electrical property measurement unit that measures electrical properties of the temperature measurement device formed on the reference semiconductor wafer. In this case, the heat source control unit controls the heat source while receiving the measurement result by the another electrical characteristic measurement unit as the target value.

  Alternatively, the semiconductor device temperature control apparatus further holds control information in which the temperature of the thermostatic chamber is associated with the measurement result of the electrical characteristics of the temperature measurement device formed on the reference semiconductor wafer. A storage unit may be provided. In this case, the heat source control unit acquires the target value with reference to the control information and controls the heat source.

  The temperature measuring device is, for example, a diode.

  According to the present invention, the temperature of a semiconductor device formed on a semiconductor wafer can be controlled with high accuracy.

1 is a configuration diagram of a semiconductor device temperature control apparatus according to a first embodiment. Configuration diagram of a semiconductor device temperature control apparatus according to a modification of the first embodiment The block diagram of the semiconductor device temperature control apparatus which concerns on 2nd Embodiment The block diagram of the system which produces | generates the control information used with the semiconductor device temperature control apparatus which concerns on 2nd Embodiment

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

<< First Embodiment >>
FIG. 1 shows a configuration of a semiconductor device temperature control apparatus according to the first embodiment. The semiconductor device temperature control apparatus 10A according to the present embodiment controls the heat source 20A to set a semiconductor device formed on the semiconductor wafer 30 to be inspected to a desired temperature. The electrical characteristic measuring units 12, 14, And a heat source controller 16A.

  The semiconductor wafer 30 is placed in a state not exposed in a room temperature environment without being housed in a sealed container such as a chamber and placed on a stage (not shown) with the electrode side facing up, and is fixed by the chuck 22. The semiconductor wafer 30 may be attracted and fixed on the chuck 22 using an electrostatic chuck, vacuum chuck, porous chuck, or the like, or the semiconductor wafer 30 may be mechanically fixed on the chuck 22 using a mechanical chuck or the like. May be.

  A heat source 20 </ b> A is disposed inside or below the chuck 22. As will be described later, the heating or cooling operation of the heat source 20A is controlled by the heat source controller 16A. The heat source 20A heats or cools the chuck 22, whereby the surface of the chuck plate can be set to a uniform temperature. The heat source 20A is a heater unit such as a ceramic heater, for example. Furthermore, the heat source 20A may include a cooling unit such as air cooling or gas cooling.

  The lower surface of the semiconductor wafer 30 and the chuck plate surface are in close contact with each other, and the entire surface of the semiconductor wafer 30 is also set to a uniform temperature by setting the chuck plate surface to a uniform temperature by the heat source 20A. .

  As described above, the semiconductor device formed on the semiconductor wafer 30 is inspected by bringing a probe card (not shown) into contact with the surface of the semiconductor wafer 30 fixed to the chuck 22 and set to a desired temperature.

  Various semiconductor elements and integrated circuits are formed on the semiconductor wafer 30. One of them is a diode 31 as a temperature measuring device. In general, the diode has a temperature dependency such that the forward voltage decreases as the temperature increases. Therefore, it is appropriate to use the diode 31 as a temperature measuring device.

  The electrical characteristic measuring units 12 and 14 are measuring devices that measure a voltage of the element while supplying a constant current to the element to be measured, or measure a current flowing through the element while supplying a constant voltage. . For example, a source measurement unit can be used as the electrical property measuring units 12 and 14.

  The electrical property measurement unit 12 measures electrical properties (voltage or current) of the diode 31 of the semiconductor wafer 30 that is heated or cooled by the heat source 20A. The semiconductor device temperature control apparatus 10 </ b> A includes a probe 11 configured to be able to contact each of an anode and a cathode of a diode 31. The electrical characteristic measurement unit 12 measures the voltage or current of the diode 31 while supplying a constant current or constant voltage to the diode 31 via the probe 11.

  On the other hand, a semiconductor wafer 30 ′ for reference is placed in the constant temperature bath 40. The semiconductor device formed on the semiconductor wafer 30 ′ has the same temperature characteristics and electrical characteristics as the semiconductor device formed on the semiconductor wafer 30 to be inspected.

  The thermostatic bath 40 is a thermostatic bath having a heat insulating structure and capable of maintaining the inside uniformly at a constant temperature for a long time regardless of the outside air temperature. By instructing the temperature controller 42 to a desired temperature, the internal temperature of the thermostatic chamber 40 is set and maintained at that temperature. By sealing the semiconductor wafer 30 ′ in the thermostat 40 for a sufficiently long period, the entire semiconductor wafer 30 ′ is kept uniformly at substantially the same temperature as the internal temperature of the thermostat 40.

  Although the temperature setting range varies depending on the individual device, it is generally from room temperature to hundreds of degrees Celsius for high-temperature types, and from minus tens to hundreds of degrees Celsius for low-temperature types equipped with a cooling unit. .

  The electrical characteristic measuring unit 14 measures the electrical characteristics of the diode 31 ′ of the semiconductor wafer 30 ′ maintained at a constant temperature in the constant temperature bath 40. Since a probe cannot be used in the thermostat 40, a measurement signal line is bonded to an electrode on the surface of the semiconductor wafer 30 '. The electrical characteristic measurement unit 14 measures the voltage or current of the diode 31 'while supplying a constant current or voltage to the diode 31' via the signal line.

  The heat source control unit 16A receives the measurement results from the electrical characteristic measurement units 12 and 14 and controls the heat source 20A based on these results. More specifically, the heat source control unit 16A compares the measurement result of the electrical property measurement unit 12 and the measurement result of the electrical property measurement unit 14, and controls the heat source 20A with a control amount corresponding to the error between the two. That is, the heat source control unit 16A controls the heating or cooling operation of the heat source 20A so that the measurement result of the electrical characteristic measurement unit 12 matches the target value with the measurement result of the electrical characteristic measurement unit 14 as a target value.

  For example, when the electrical characteristic measurement units 12 and 14 output analog signals as measurement results, the heat source control unit 16A can be realized by an analog comparator.

  Alternatively, when the electrical characteristic measuring units 12 and 14 each output a digital value as a measurement result, or an analog signal output by each of the electrical characteristic measuring units 12 and 14 as a measurement result is appropriately sampled by an AD converter (not shown). In the case of converting to a digital value, the heat source control unit 16A can be realized by a digital signal processor.

  As described above, according to the present embodiment, the diode 31 ′ of the reference semiconductor wafer 30 ′ in which the electrical characteristics of the diode 31 of the semiconductor wafer 30 to be inspected are exactly the desired temperature in the thermostatic chamber 40. The heat source 20A is controlled so as to have the same electrical characteristics. That the electrical characteristics of the diodes 31 and 31 'are the same can be considered that the temperatures of the semiconductor devices formed on the semiconductor wafers 30 and 30' are the same. That is, it can be considered that the current temperature of the semiconductor device formed on the semiconductor wafer 30 to be inspected is equal to the temperature set in the thermostat 40. Therefore, the temperature of the semiconductor device formed on the semiconductor wafer 30 to be inspected can be controlled with high accuracy equivalent to the set temperature of the constant temperature bath 40.

  Note that the heat source 20 </ b> A may be replaced with a heat source that heats or cools the semiconductor wafer 30 from above the semiconductor wafer 30. FIG. 2 shows a configuration of a semiconductor device temperature control apparatus according to a modification. The heat source 20 </ b> B is, for example, a thermostreamer that blows hot air or cold air 100 toward the surface of the semiconductor wafer 30 from the top of the semiconductor wafer 30. Or the heater which irradiates heat rays, such as infrared rays, can be used as the heat source 20B.

  Further, the semiconductor wafer 30 may be simultaneously heated or cooled from the upper part and the lower part by using the heat sources 20A and 20B together.

<< Second Embodiment >>
FIG. 3 shows the configuration of the semiconductor device temperature control apparatus according to the second embodiment. The semiconductor device temperature control apparatus 10B according to the present embodiment controls the heat source 20A to set the semiconductor device formed on the semiconductor wafer 30 to be inspected to a desired temperature. The electrical characteristic measurement unit 12, the heat source control A unit 16B and a storage unit 18 are provided. Only differences from the first embodiment will be described below.

  The storage unit 18 holds control information representing the correspondence between the temperature desired to be set for the semiconductor device formed on the semiconductor wafer 30 to be inspected and the electrical characteristics of the diode 31 at that temperature. The storage unit 18 can be realized by a RAM, a flash memory, a hard disk device, or the like.

  The heat source control unit 16 </ b> B receives the measurement result from the electrical property measurement unit 12 and acquires the target value with reference to the control information held in the storage unit 18. Then, the heat source control unit 16B controls the heating or cooling operation of the heat source 20A so that the measurement result of the electrical characteristic measurement unit 12 matches the target value.

  FIG. 4 shows a configuration of a system that generates control information used in the semiconductor device temperature control apparatus 10B according to the present embodiment. In the system, the electrical property measurement unit 14 measures electrical properties of the diode 31 ′ of the reference semiconductor wafer 30 ′ placed in the thermostatic chamber 40. As described above, the inside of the thermostatic chamber 40 is set and maintained at a temperature as instructed by the temperature controller 42. Therefore, the electrical characteristics of the diode 31 ′ at each temperature are measured in advance by changing the temperature of the thermostatic chamber 40 in various ways. The above control information is generated from the correspondence relationship between the measured electrical characteristics and each temperature.

  As described above, according to the present embodiment, the constant temperature bath 40 and the reference semiconductor wafer 30 ′ are not prepared, and the semiconductor wafer 30 ′ is formed on the semiconductor wafer 30 to be inspected using the results measured in advance. The temperature control of the semiconductor device can be performed with high accuracy. Thereby, the apparatus configuration is simplified. In addition, by using a plurality of control information, high-precision temperature control can be performed for various semiconductor devices formed on various types of semiconductor wafers.

  Note that the semiconductor device temperature control apparatus 10B according to the present embodiment can be modified so that the heat source 20A is replaced with or used together with the heat source 20B as shown in FIG.

  In addition, the semiconductor device temperature control apparatuses 10A and 10B according to the above embodiments and modifications can be incorporated in a semiconductor inspection apparatus, and the temperature of the semiconductor device can be controlled with high accuracy during inspection.

  The semiconductor device temperature control apparatus according to the present invention can accurately control the temperature of a semiconductor device to be inspected, and thus is useful for a semiconductor inspection apparatus that inspects a wafer level semiconductor device.

10A, 10B Semiconductor device temperature control device 12 Electrical characteristic measurement unit 14 Electrical characteristic measurement unit (another electrical characteristic measurement unit)
16A, 16B Heat source control unit 18 Storage unit 20A, 20B Heat source 30 Semiconductor wafer (semiconductor wafer to be inspected)
30 'semiconductor wafer (semiconductor wafer for reference)
31 Diode (temperature measurement device formed on the semiconductor wafer to be inspected)
31 'diode (temperature measurement device formed on a reference semiconductor wafer)

Claims (4)

A semiconductor device temperature control apparatus for controlling a heat source to set a semiconductor device formed on a semiconductor wafer to be inspected to a desired temperature,
A probe configured to be able to contact a temperature measuring device formed on the semiconductor wafer;
An electrical property measurement unit that measures electrical properties of the temperature measurement device via the probe in a state where the semiconductor wafer is heated or cooled by the heat source;
A heat source control unit that receives the measurement result and the target value by the electric characteristic measurement unit, and controls the heat source so that the measurement result by the electric characteristic measurement unit matches the target value;
The target value is determined based on a measurement result of electrical characteristics of a temperature measurement device formed on a reference semiconductor wafer placed in a thermostatic chamber maintained at the desired temperature. A semiconductor device temperature control apparatus. Comprising another electrical property measuring unit for measuring electrical properties of the temperature measuring device formed on the reference semiconductor wafer;
The semiconductor device temperature control apparatus according to claim 1, wherein the heat source control unit controls the heat source while receiving a measurement result by the another electrical characteristic measurement unit as the target value. A storage unit that holds control information in which the temperature of the thermostat and the measurement result of the electrical characteristics of the temperature measurement device formed on the reference semiconductor wafer are associated;
The semiconductor device temperature control apparatus according to claim 1, wherein the heat source control unit acquires the target value with reference to the control information and controls the heat source.   The semiconductor device temperature control apparatus according to claim 1, wherein the temperature measuring device is a diode.

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