JP2000138269A - Burn-in equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly heat a wafer and a contacter, when burn-in in a state of a wafer is performed. SOLUTION: A main heater heating a wafer tray 11 accommodating a wafer, and a subheater 14 for heating a contacter 13 which is in contact with an electrode of a semiconductor chip on the wafer and applies a signal are installed. A DUT substrate 15 supplies a signal to the contacter 13. A temperature adjuster is operated on the basis of a temperature of the wafer tray 11, a temperature of the contacter 13, and a temperature where the temperature of the contacter 13 is subtracted from the temperature of the wafer tray 11. Through the use of PID control, heating speeds of the main heater, which is brought into contact with the wafer tray 11 and the subheater 14 for heating the contacter 13 are optimized, temperature rising speed of the wafer tray heated with the main heater, is made to match with temperature rising speed of the contacter 13 heated with the subheater 14, the temperature difference between the wafer 12 and the contacter 13 is precluded, and the temperature rise of the wafer tray 11 and the contacter 13 is made uniform. As a result, stable heating can be made in a burn-in in a wafer state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burn-in apparatus and, more particularly, to a burn-in apparatus for performing a screening process by burn-in of a semiconductor device in a wafer state.

[0002]

2. Description of the Related Art Conventionally, as a screening process for improving the reliability of a semiconductor device, a power supply voltage due to a rating or a slight overvoltage is applied to the semiconductor device, and a signal close to an actual operation is applied to each signal input terminal. Burn-in is performed for several hours at a high temperature of about 125 ° C. Conventionally, this burn-in processing has often been performed in a product state in which a semiconductor device is housed in a package. FIG. 8 shows a heating method used at this time.

In FIG. 8, reference numeral 32 denotes a furnace in which burn-in is performed. Reference numeral 41 denotes a fan, which allows air to circulate in the furnace 32. 42 is a heater for heating the circulating air. Reference numeral 43 denotes a flow straightening plate, which has a role to make the circulating air flow evenly. Reference numeral 15 denotes a DUT substrate on which a number of semiconductor devices 44 are mounted. As described above, when a conventional packaged semiconductor device is burned in, air is circulated in a furnace containing the semiconductor device, the air is heated by a heater, and the semiconductor device is indirectly heated by high-temperature air. Many approaches have been used.

[0004]

In recent years, however, it has been desired to perform burn-in on semiconductor chips in a wafer state for the purpose of performing screening in a more upstream process. In order to realize burn-in for a semiconductor chip in a wafer state, a plurality of semiconductor chips formed on the wafer are connected in advance to a contactor for leading a signal line, and a cassette in which the wafer and the contactor are integrated is handled. . FIG. 9 shows the structure of the cassette.

In FIG. 9, reference numeral 11 denotes a wafer tray,
The wafer 12 is housed therein. Reference numeral 13 denotes a contactor, which can be connected to an electrode of a semiconductor chip on the wafer 12 by a contact and a signal line formed on the contactor 13 to apply a signal. Reference numeral 15 denotes a DUT board, and a contactor 13
To the signal. Reference numeral 16 denotes a connector, which has a role of extracting a signal of a signal line formed on the contactor 13 to the DUT board 15.

In performing burn-in, the wafer 12 is
As a method of heating the entire cassette to heat to 125 ° C., there is a conventional indirect heating method using air. However, to heat at a higher speed, there is a method of directly heating the wafer tray 11 by a heater. FIG. 10 shows a conventional method in which a cassette containing wafers is housed in a furnace and directly heated by a heater.

In FIG. 10, reference numeral 32 denotes a furnace in which the entire apparatus is housed. Reference numeral 17 denotes a cassette, which includes a wafer tray 11, a wafer 12, a contactor 13, and a DUT substrate 15. Reference numeral 42 denotes a heater, which is arranged on the furnace 32 side of the cassette 17 below the wafer tray 11. When performing burn-in, the cassette 17 is heated by the heater 42.

In a conventional heating method in which a heater is brought into contact with a wafer tray, a contactor is used to contact a wafer tray 11 with a wafer.
Since the heat was indirectly heated via 12, the heat conduction from the heater 42 was not uniform, and the temperature rise of the contactor was not uniform.

Further, in the conventional heating method, the temperature rise of the contactor is delayed as compared with the temperature rise of the wafer, so that a temperature difference occurs between the wafer and the contactor, and the connection between the wafer and the contactor becomes unstable. was there.

When the burn-in is sequentially performed by using a structure in which the cassette 17 can be easily replaced, a gap is easily generated between the heater 42 and the wafer tray 11. Therefore, there was a problem that heating became unstable.

The present invention solves the above-mentioned problems of the conventional burn-in apparatus, and enables the stabilization of the heating required for the burn-in in the wafer state to be performed easily and stably, thereby enabling the burn-in in the wafer state. The purpose is to:

[0012]

According to the present invention, in order to solve the above-mentioned problems, a sub-heater for directly heating a contactor is provided in a burn-in apparatus. With this configuration, the entire cassette can be uniformly heated by the main heater for heating the wafer tray and the sub-heater for heating the contactor.

Further, a means for controlling the temperature based on a difference between the temperature of the wafer, the temperature of the contactor, and the temperature of the wafer and the contactor is provided. With this configuration, the heating speed of the main heater that contacts the wafer tray and the sub-heater that heats the contactor is optimized, and the temperature rise speed of the wafer tray that is heated by the main heater and the temperature rise of the contactor that is heated by the sub-heater By matching the speeds, preventing different heating speeds and preventing a temperature difference between the wafer and the contactor, the entire cassette is uniformly heated by the main heater for heating the wafer tray and the sub-heater for heating the contactor. be able to.

Further, the burn-in apparatus is provided with heating means by an electromagnetic heating method on the furnace side, a layer containing iron is formed on the wafer tray and, if necessary, the contactor, and the wafer tray for accommodating the wafer and the contactor as necessary. It was configured to perform direct electromagnetic heating. With this configuration, it is easy to stably heat the wafer,
Burn-in in a wafer state becomes possible.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION
A burn-in apparatus comprising: a first heater in close contact with a wafer tray for accommodating a wafer; a second heater in close contact with a contactor; and control means for heating the wafer and the contactor by the first heater and the second heater. This has the effect of uniformly heating the entire cassette with the two heaters.

According to a second aspect of the present invention, a first heater that is in close contact with a wafer tray for accommodating a wafer, a second heater that is in close contact with a contactor, and the temperature of the wafer is measured in close contact with the wafer or the wafer tray. A first temperature sensor, a second temperature sensor that is in close contact with the contactor and measures a contactor temperature, and receives a difference between the wafer temperature and the contactor temperature as input, controls the first heater and the second heater, and A burn-in device comprising a PID control device for heating a wafer and the contactor, wherein the temperature rise speed of the wafer tray and the contactor temperature rise speed are matched to prevent a temperature difference between the wafer and the contactor. Has an action.

According to a third aspect of the present invention, there is provided a wafer tray which contains a magnetic substance such as iron and raises the temperature of a wafer housed by heat generated by eddy current loss, and a magnetic field line which is arranged around the wafer tray and which is driven by a high-frequency current. This is a burn-in device having an electromagnetic coil generated, and has an effect of heating a wafer by heat generation of a wafer tray due to eddy current loss.

According to a fourth aspect of the present invention, there is provided a wafer tray which contains a magnetic substance such as iron and raises the temperature of a wafer accommodated by heat generated by eddy current loss, and a heat tray which contains a magnetic substance such as iron and generated by eddy current loss. A contactor that raises the temperature of the contacted wafer, and an electromagnetic coil that is arranged around the wafer tray and the contactor and generates magnetic lines of force by high-frequency current. It has the effect of heating the wafer.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described in detail with reference to FIGS.

(First Embodiment) In a first embodiment of the present invention, a heater which is in close contact with a wafer tray for accommodating a wafer and a heater which is in close contact with a contactor are provided, and the wafer temperature and the contactor temperature are measured. , A burn-in device in which a PID controller controls two heaters based on a difference between a wafer temperature and a contactor temperature to heat a wafer and a contactor.

FIG. 1 is a sectional view of a cassette including a sub-heater in a burn-in device according to a first embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a wafer tray in which a wafer 12 is stored. Reference numeral 13 denotes a contactor, which can be connected to an electrode of a semiconductor chip on the wafer 12 by a contact and a signal line formed on the contactor 13 to apply a signal. Reference numeral 14 denotes a sub-heater, which is a heater for heating the contactor 13. Reference numeral 15 denotes a DUT board which supplies a signal to the contactor 13. 16
Is a connector, which has a role of drawing out a signal of a signal line formed on the contactor 13 to the DUT board 15.

Next, FIG. 2 shows an example of control means for heating the cassette with the sub-heater shown in FIG. 1 together with the main heater. In FIG. 2, reference numeral 17 denotes a cassette, which includes a wafer tray 11, a wafer 12, a contactor 13, and a sub-heater 1.
4. It is composed of a DUT board 15, a main sensor 18, and a sub-sensor 19, and is housed in a fixed position of the furnace. Reference numeral 20 denotes a main temperature controller A, which controls the temperature by the output of the main sensor 18. Reference numeral 21 denotes a main subtractor, which subtracts the output value of the sub sensor 19 from the output value of the main sensor 18. Reference numeral 22 denotes a main temperature controller B, which controls the temperature by the output of the main subtractor 21. Reference numeral 23 denotes a sub-temperature controller A, which controls the temperature by the output of the sub-sensor 19. twenty four
Is a sub subtracter, which subtracts the output value of the sub sensor 19 from the output value of the main sensor 18. 25 is the sub temperature controller B
The temperature is adjusted by the output of the sub-subtractor 24. 26 is a main SSR-A, and a main temperature controller A2
The output of 0 controls the power sent to the main heater 30. 27 is a main SSR-B and a main temperature controller B2
The power output to the main heater 30 is controlled by the output of (2). Two
Reference numeral 8 denotes a sub-SSR-A, which controls the power to be sent to the sub-heater 14 by the output of the sub-temperature controller A23. 29 is sub S
SR-B, which controls the power sent to the sub-heater 14 by the output of the sub-temperature controller B25.

Next, the operation will be described with reference to FIGS.
When the cassette 17 is stored in the furnace, the power is turned on to the entire control device and the operation starts. First, the target temperature of 125 ° C. is set for the main temperature controller A20, and the target temperature of 125 ° C. is also set for the sub temperature controller A23. Main temperature controller B2
2 and the sub temperature controller B25 are set to 10 ° C., which is an allowable value of the difference between the temperature of the wafer tray 11 and the temperature of the contactor 13. The main temperature controller A20 receives the output of the main sensor 18 and sends an ON signal to the main SSR-A26 because the temperature of the wafer tray 11 is as low as 25 ° C., and the main SSR-A26 is turned on. At the same time, the sub-temperature controller A23 receives the output of the sub-sensor 19 and sends an ON signal to the sub-SSR-A28 because the temperature of the contactor 13 is as low as 25 ° C., and the sub-SSR-A28 is turned on.

Further, the main temperature controller B25 receives the difference between the outputs of the main sensor 18 and the sub-sensor 19, the temperatures of the wafer tray 11 and the contactor 13 are both 25 ° C., and the difference is 0. An ON signal is sent to B27, and the main SSR-B27 is turned on. Further, the sub-temperature controller B25 receives the difference between the outputs of the main sensor 18 and the sub-sensor 19, the temperatures of the wafer tray 11 and the contactor 13 are both 25 ° C., and the difference is 0. A signal is sent, and the sub-SSR-B29 is turned on. Since both the main SSR-A26 and the main SSR-B27 are turned on, the maximum power is sent to the main heater 30 to start heating. Since both the sub-SSR-A28 and the sub-SSR-B29 are turned on, the maximum power is sent to the sub-heater 14 to start heating.

In this way, the main heater 30 and the sub-heater 14 start heating, and the heating speed of the wafer tray 11 by the main heater 30 and the contactor by the sub-heater 14
There is a difference between the 13 heating rates. When the heating speed of the contactor 13 by the sub-heater 14 is faster than the heating speed of the wafer tray 11 by the main heater 30, the temperature rise of the contactor 13 is high as shown in FIG. The temperature difference of 13 is 10 ° C. At this point, the sub temperature controller B25
And the difference between the outputs of the sub sensor 19 and the wafer tray
Since the difference between the temperatures of 11 and 13 is 10 ° C,
An off signal is sent to the sub SSR-B29,
B29 narrows the flow angle to be turned on, and limits the electric power sent to the sub-heater 14.

Therefore, in the portion C, the temperature rise rate is lower than that in the portion A, and the temperature difference between the wafer tray 11 and the contactor 13 is kept within 10 ° C. As described above, the heating of the sub-heater 14 is continued as the main heater 30 heats, and when the heating of the wafer tray 11 by the main heater 30 reaches 125 ° C., the power sent from the main temperature controller A20 to the main heater 30 is controlled, and the wafer tray Keep the temperature of 11 at 125 ° C.
Similarly, when the heating of the contactor 13 by the sub-heater 14 reaches 125 ° C., the sub-temperature controller A 23
4 to control the power sent to
To keep.

That is, when the temperature rises, the power of the sub-heater 14 is controlled by the sub-temperature controller B25 so that a temperature difference between the wafer tray 11 and the contactor 13 does not occur. When the temperature reaches the target, the contactor is controlled by the sub-temperature controller A23. Keep 13 at target temperature.

As described above, in the first embodiment of the present invention, the burn-in device is provided with a heater that is in close contact with the wafer tray that stores the wafer and a heater that is in close contact with the contactor, and measures the wafer temperature and the contactor temperature. Then, based on the difference between the wafer temperature and the contactor temperature, the PID controller controls the two heaters to heat the wafer and the contactor. Therefore, the temperature rise speed of the wafer tray heated by the main heater and the sub-heater By matching the temperature rise rate of the contactor to be heated to prevent a temperature difference between the wafer and the contactor, it is possible to uniformly heat the entire cassette by the main heater for heating the wafer tray and the sub-heater for heating the contactor. it can.

(Second Embodiment) In a second embodiment of the present invention, a wafer is housed in a tray containing a magnetic substance such as iron, and a high-frequency current is applied to an electromagnetic coil disposed around the wafer to generate the wafer. This is a burn-in device that raises the temperature of the wafer due to eddy current loss of the lines of magnetic force.

FIG. 4 is a diagram showing a burn-in device according to a second embodiment of the present invention. In FIG. 4, a furnace 32 houses the entire apparatus therein. Electromagnetic coil 33
Is a coil that is arranged on the furnace side near the object to be heated and generates magnetic lines of force for performing electromagnetic heating. The oscillator 34
This is a device for supplying a high-frequency current to the electromagnetic coil 33. Cassette 17 includes wafer tray 11, wafer 12, contactor 13,
It is constituted by a DUT board 15 and housed in a fixed position of a furnace 32. The wafer tray 11 has the structure shown in FIG.

In FIG. 5, a wafer tray 11 is made of an aluminum material or the like in order to improve heatability while having appropriate rigidity, and stores a wafer 12 therein. The iron plate 35 is adhered to the lower portion of the wafer tray 11 or is adhered to the wafer tray 11 by vapor deposition by sputtering.

The operation of the burn-in device configured as described above will be described. When the cassette 17 is stored in the furnace 32, the oscillator 34 is operated to supply a high-frequency current to the electromagnetic coil 33. The magnetic coil 33 shown in FIG. 4 emits magnetic force lines 36 that change at the frequency of the high-frequency current. This line of magnetic force 36
Concentrates on the portion of the iron plate 35 attached to the lower portion of the wafer tray 11, where an eddy current is generated. Due to the loss of the eddy current, the wafer tray 11 is rapidly heated. Oscillator
The output of 34 is controlled by measuring the temperature of the wafer tray 11 so that the temperature of the wafer 12 can be kept constant.

As described above, according to the second embodiment of the present invention, a burn-in device is used to store a wafer in a wafer tray containing a magnetic substance such as iron and to generate a high-frequency current by flowing an electromagnetic coil disposed around the wafer tray. Since the temperature of the wafer is raised by the eddy current loss of the lines of magnetic force, the wafer can be stably heated by the heat of the wafer tray.

(Third Embodiment) In a third embodiment of the present invention, a wafer is accommodated in a wafer tray containing a magnetic substance such as iron, and a contactor substrate containing a magnetic substance such as iron is brought into contact with the wafer. This is a burn-in device that raises the temperature of the wafer and the contactor substrate by eddy current loss of lines of magnetic force generated by flowing a high-frequency current through an electromagnetic coil arranged around the tray and the contactor substrate.

FIG. 6 is a sectional view of a burn-in device according to a third embodiment of the present invention. In FIG. 6, a furnace 32 accommodates the entire apparatus therein. Electromagnetic coil A37
Is placed on the furnace side near the wafer tray to be heated,
This is a coil that generates lines of magnetic force for performing electromagnetic heating. The oscillator A38 is a circuit that supplies a high-frequency current to the electromagnetic coil A37. The electromagnetic coil B39 is a coil that is arranged on the furnace side near the contactor to be heated and generates lines of magnetic force for performing electromagnetic heating. The oscillator B40 is a circuit that supplies a high-frequency current to the electromagnetic coil B39. The cassette 17 includes a wafer tray 11, a wafer 12, a contactor 13, and a DUT substrate 15, and is stored in a furnace 32 at a predetermined position. The wafer tray 11 has the structure shown in FIG.

The contactor 13 has the structure shown in FIG. In FIG. 7, a contactor 13 contacts an electrode of a semiconductor chip on a wafer and supplies a signal. Therefore, it is necessary to be made of a material having the same coefficient of thermal expansion as the wafer and to maintain the same temperature as the temperature of the wafer. The iron plate 35 is adhered to the upper part of the contactor 13 or adhered to the contactor 13 by vapor deposition by sputtering. The DUT board 15 is a contactor 13
To supply signals to The connector 16 has a role of drawing out a signal of a signal line formed on the contactor 13 to the DUT board 15.

The operation of the burn-in device configured as described above will be described. When the cassette 17 is stored in the furnace 32, the oscillator A38 is operated to supply a high-frequency current to the electromagnetic coil A37. Magnetic field lines 36 that change at the frequency of the high-frequency current are radiated from the electromagnetic coil A37 shown in FIG. The lines of magnetic force 36 correspond to the iron plate 35 attached to the lower part of the wafer tray 11.
Where eddy currents are generated. Due to the loss of the eddy current, the wafer tray 11 is rapidly heated. The output of the oscillator A38 is controlled by measuring the temperature of the wafer tray 11, so that the temperature of the wafer 12 can be kept constant.

At the same time, when the cassette 17 is stored in the furnace 32, the oscillator B40 is operated to supply a high-frequency current to the electromagnetic coil B39. From the electromagnetic coil B39 shown in FIG.
Magnetic field lines 36 that change at the frequency of the high-frequency current are emitted.
The lines of magnetic force 36 are concentrated on the portion of the iron plate attached to the upper part of the contactor 13, where an eddy current is generated. The contactor 13 is rapidly heated by the loss of the eddy current.
The output of the oscillator B40 is controlled by measuring the temperature of the contactor 13, so that the temperature of the contactor 13 can be kept constant. The contactor 13 can be heated without a direct heater contact.

As described above, in the third embodiment of the present invention, a burn-in device is used to store a wafer in a tray containing a magnetic substance such as iron and to attach a contactor substrate containing a magnetic substance such as iron to the wafer. When the tray and the contactor substrate are heated, the temperature of the wafer and the contactor substrate is raised by eddy current loss of the lines of magnetic force generated by flowing a high-frequency current through the electromagnetic coil arranged around the tray and the contactor substrate. Can be stably heated.

[0040]

As is apparent from the above description, according to the present invention, a burn-in device is provided with a heater which is in close contact with a wafer tray for accommodating a wafer and a heater which is in close contact with a contactor, and measures the wafer temperature and the contactor temperature. Based on the difference between the wafer temperature and the contactor temperature, the PID controller controls the two heaters to heat the wafer and the contactor, so that the entire cassette is heated by the main heater that heats the wafer tray and the sub-heater that heats the contactor. The uniform heating can be achieved, and the effect of easily heating the wafer and the contactor appropriately can be obtained.

Further, the burn-in device is configured such that the wafer is housed in a wafer tray containing a magnetic substance such as iron, and a high-frequency current is applied to an electromagnetic coil disposed around the wafer to increase the temperature of the wafer due to eddy current loss of the lines of magnetic force generated. Therefore, the effect that the wafer can be easily and stably heated by the heat generation of the wafer tray is obtained.

Further, the burn-in device is used to store a wafer in a wafer tray containing a magnetic substance such as iron, and to bring a contactor containing a magnetic substance such as iron into contact with the wafer, and to use an electromagnetic coil disposed around the wafer tray and the contactor. Since the temperature of the wafer and the contactor is increased by the eddy current loss of the lines of magnetic force generated by flowing the high-frequency current, the effect of easily and stably heating the wafer by the heat generated by the wafer tray and the contactor is obtained.

[Brief description of the drawings]

FIG. 1 is a view of a cassette including a sub-heater in a burn-in device according to a first embodiment of the present invention;

FIG. 2 is a diagram of a burn-in device according to the first embodiment of the present invention;

FIG. 3 is a diagram showing an operation of the burn-in device according to the first embodiment of the present invention;

FIG. 4 is a sectional view of a burn-in device according to a second embodiment of the present invention;

FIG. 5 is a view of a wafer tray of a burn-in device according to a second embodiment of the present invention;

FIG. 6 is a sectional view of a burn-in device according to a third embodiment of the present invention;

FIG. 7 is a diagram of a contactor substrate of a burn-in device according to a third embodiment of the present invention;

FIG. 8 is a diagram of a conventional burn-in device,

FIG. 9 is a view of a cassette for burning in a wafer.

FIG. 10 is a diagram illustrating a conventional heating method.

[Explanation of symbols]

 11 Wafer tray 12 Wafer 13 Contactor 14 Sub heater 15 DUT board 16 Connector 17 Cassette 18 Main sensor 19 Sub sensor 20 Main temperature controller A 21 Main subtractor 22 Main temperature controller B 23 Sub temperature controller A 24 Sub subtracter 25 Sub temperature control Unit B 26 Main SSR-A 27 Main SSR-B 28 Sub SSR-A 29 Sub SSR-B 30 Main heater 31 Power supply 32 Furnace 33 Electromagnetic coil 34 Oscillator 35 Iron plate 36 Magnetic field line 37 Electromagnetic coil A 38 Oscillator A 39 Electromagnetic coil B 40 Oscillator B 41 Fan 42 Heater 43 Rectifier plate 44 Semiconductor device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yumio Nakamura 246 Sachika, Sazaka, Nagano Prefecture Inside Orion Machinery Co., Ltd. F-term (reference) 4M106 AA01 BA14 CA56 CA60 DH01 DH44

Claims (4)

[Claims] A first heater that is in close contact with a wafer tray that stores wafers, a second heater that is in close contact with a contactor,
A burn-in apparatus, comprising: control means for heating a wafer and a contactor by the first heater and the second heater. 2. A first heater in close contact with a wafer tray for accommodating a wafer, a second heater in close contact with a contactor,
A first temperature sensor that measures the wafer temperature in close contact with the wafer or the wafer tray, a second temperature sensor that measures the contactor temperature in close contact with the contactor, and a difference between the wafer temperature and the contactor temperature as inputs;
A burn-in device, comprising: a PID control device that controls the first heater and the second heater to heat the wafer and the contactor. 3. A wafer tray which contains a magnetic substance such as iron and raises the temperature of a wafer housed by heat generated by eddy current loss, and an electromagnetic coil which is arranged around the wafer tray and generates lines of magnetic force by high-frequency current. A burn-in device. 4. A wafer tray that contains a magnetic substance such as iron and raises the temperature of a stored wafer by heat generated by eddy current loss, and a wafer tray that contains a magnetic substance such as iron and raises the temperature of a wafer contacted by heat generated by eddy current loss. A burn-in apparatus, comprising: a contactor; and an electromagnetic coil that is arranged around the wafer tray and the contactor and generates magnetic lines of force by a high-frequency current.