JP4134940B2 - Performance board diagnostic method and diagnostic device - Google Patents

Description

  The present invention relates to a technique for diagnosing a performance board.

In the manufacturing process of a semiconductor device, a plurality of dies (chips) are formed on a wafer. Prior to cutting the wafer into dies (dicing), a test is performed to confirm that each die is correctly manufactured. A semiconductor test apparatus is used for this test. The semiconductor test apparatus includes a wafer prober, a test head, and a tester. The wafer prober is formed in a box shape and includes a probe card, a changer, and a chuck inside. The probe card has a plurality of probe needles. The probe needle contacts the die pad built into the wafer to be tested. The changer is used to replace the probe card. The chuck moves in a state where the wafer is held, thereby bringing the dies into contact with the probe needles of the probe card sequentially.
The test head opens and closes a wafer prober and includes a main body, a first pogo tower, a performance board, and a second pogo tower. The performance board is attached to the main body via the first pogo tower. The second pogo tower is connected to the performance board. When the test head is closed, the second pogo tower of the test head and the probe card of the wafer prober come into contact with each other, and the performance board and the probe card are connected via the second pogo tower.
The tester is connected to the performance board via the first pogo tower of the test head and tests the die by executing a programmed test program.

Of course, if a performance board fails, the die cannot be properly tested. For this reason, it is necessary to diagnose the performance board. When diagnosing a performance board, in the conventional technology, the performance board is removed from the test head and connected to a separately prepared diagnostic device to diagnose the performance board.
In addition, it is necessary to diagnose a tester, and Patent Documents 1 and 2 describe techniques for diagnosing a tester using a performance board.
JP 2000-266822 A JP 2001-74816 A

In the conventional technique, the performance board is removed from the test head and diagnosed, and then attached to the test head after diagnosis. This operation requires great care and takes a long time.
Therefore, a technique capable of efficiently diagnosing a performance board is desired. The present invention has been made to solve such a problem, and provides a technique capable of efficiently diagnosing a performance board.

In the present invention, in order to efficiently diagnose a performance board, a diagnostic method and a diagnostic device have been created. Diagnostic board used in diagnostic device and diagnostic method was created in the present invention, like the probe card can be exchanged in the c Ehapuroba. A probe card that is a reference of dimension of the diagnostic board is connected to the performance board, with contacting a probe needle to a pad of a die that is fabricated on the wafer, it means a replaceable within c Ehapuroba. The diagnostic board diagnostic circuitry of the performance board are formed.
The diagnostic board used in the diagnostic method and diagnostic device created in the present invention can be replaced with a probe card . Thereby , it is possible to switch from the state in which the performance board and the probe card are connected to the state in which the performance board and the diagnostic board are connected.
Since a diagnostic circuit for the performance board is formed on this diagnostic board, the performance board can be diagnosed by switching to a state in which the diagnostic board is connected to the performance board. When the diagnosis is completed, it is possible to switch from the state in which the diagnostic board is connected to the performance board to the state in which the probe card is connected to the performance board by using a changer. The performance board can be diagnosed without removing the performance board from the test head.

The diagnostic circuit formed on the diagnostic board can be an equivalent circuit to the circuit formed when the probe needle of the probe card is brought into contact with a die whose pads are short-circuited.
In this case, the tester only needs to execute a test program for testing a die that should be short-circuited between pads, and if the test result is incorrect, it can be diagnosed that the performance board is abnormal. When the above-described diagnostic board is used, the failure location of the performance board can be specified.

Alternatively, the diagnostic circuit may be formed by mounting a master die on a printed board having the same dimensions as the probe card. This master die is a die that has been confirmed to be normal.
If the result of testing a master die that should be normal is strange, it can be diagnosed that the performance board is abnormal.
When a master die is used, a diagnostic circuit can be easily prepared. In addition, the performance board can be diagnosed in a state close to actual operation.

In the performance board diagnostic method created in the present invention, a step of preparing a diagnostic board that is replaceable with a probe card and on which a diagnostic circuit for the performance board is formed, and the diagnostic board is replaced with a probe card for performance. Execute the process of connecting to the board .
According to this diagnosis method, the performance board can be diagnosed without removing the performance board from the test head. The performance board can be diagnosed efficiently.

In the diagnostic methods described above, diagnose performance board by changing the temperature of the wafer prober.
By changing the temperature in the wafer prober, the performance board can be diagnosed in various temperature environments. For example, even if it is normal at normal temperature, it can detect an abnormality in the performance board that becomes abnormal when exposed to high temperatures. Furthermore, diagnosis can be performed in a state that includes a change in the characteristics of the die accompanying a temperature change.

Diagnostic apparatus of the present invention includes a diagnostic board, and the wafer prober can change the internal temperature, the testers diagnostic program performance board is programmed. Diagnostic board is "connected to the performance board, with contacting a probe needle to a pad of a die that is built into the wafer, a probe card that has a replaceable within the wafer prober by changer" as interchangeable Yes, a performance board diagnostic circuit is formed. Prober comprises a changer for exchanging the probe card (hence the same diagnostic board equivalent dimension). The diagnostic board is transported by the changer and connected to the performance board.
According to this performance board diagnostic apparatus, the performance board can be diagnosed without removing the performance board from the test head. The performance board can be diagnosed efficiently. By changing the temperature in the wafer prober, the performance board can be diagnosed in various temperature environments. For example, even if it is normal at normal temperature, it can detect an abnormality in the performance board that becomes abnormal when exposed to high temperatures. Furthermore, diagnosis can be performed in a state that includes a change in the characteristics of the die accompanying a temperature change.

The main features of the first embodiment and the second embodiment described later will be described.
(First form)
(1) The semiconductor test apparatus includes a test head, a wafer prober, and a tester. The test head has a test head body, a first pogo tower, a performance board, and a second pogo tower. The wafer prober includes a wafer prober main body, a probe card, a chuck, a chuck driving mechanism, and a changer. The tester is connected to the test head by a cable.
(2) When diagnosing a probe card, a changer is used to mount a diagnostic board instead of the probe card. The diagnostic board is formed in the same shape as the probe card. On the diagnostic board, a circuit equivalent to a circuit formed when a probe needle of a probe card is brought into contact with a die whose pads are short-circuited is formed. From another point of view, this circuit can be said to be a circuit formed by the probe card when the probe needle of the probe card is short-circuited. can do.
If a test result that is not short-circuited is measured when testing between probe needles that should be short-circuited, it is diagnosed that there is an abnormality in the circuit connected to the probe needle in the circuit formed on the performance board. To do.

(Second form)
(1) Similar to the first embodiment, a diagnostic board is used instead of the probe card. A master die is mounted on the diagnostic board.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the semiconductor test apparatus 10 includes a test head 12, a wafer prober 14, and a tester 16.
The test head 12 includes a test head main body 20, a first pogo tower 21, a performance board 22, and a second pogo tower 23. The performance board 22 is connected to the test head main body 20 via the first pogo tower 21. The first pogo tower 21 is provided with a plurality of pogo pins (not shown). The performance board 22 is a substrate on which an electric circuit is formed, and a different performance board 22 is used for each type of wafer 32 (described later) to be tested by the semiconductor test apparatus 10. The second pogo tower 23 is attached to the performance board 22, and a plurality of pogo pins are provided in the same manner as the first pogo tower. The test head main body 20 is connected to the wafer prober 14 by a hinge 26. The wafer prober 14 is opened and closed as the test head 12 rotates about the hinge 26. FIG. 1 illustrates a state in which the wafer prober 14 is closed by the test head 12. In a state where the wafer prober 14 is closed, the pogo pins of the second pogo tower 23 of the test head 12 are in electrical contact with a probe card 24 described later.

The wafer prober 14 includes a wafer prober main body 30, a probe card 24, a chuck 31, a chuck drive mechanism (not shown), and a changer 33. The probe main body 30 is formed in a box shape, and accommodates therein a probe card 24, a chuck 31, a chuck driving mechanism, a changer 33, and the like. The probe card 24 is a disk-shaped substrate, and includes an electric circuit and a plurality of probe needles 25 connected to the electric circuit. The probe needle 25 is disposed in the center of the lower surface of the probe card 24 so as to face downward. The tip of the probe needle 25 contacts a die bonding pad formed on the wafer 32 when the wafer 32 is tested. The chuck 31 is driven by the chuck driving mechanism and moves in the horizontal / vertical directions while holding the wafer 32 on the upper surface thereof. The chuck driving mechanism drives the chuck 31 to sequentially bring the probe needles 25 of the probe card 24 into contact with the pads of the dies on the wafer 32. When the probe needle 25 of the probe card 24 is in contact with the die pad, an electrical path from the die to the probe needle 25, the second pogo tower 23, the performance board 22, the first pogo tower 21, and the test head 20 is formed. The
The tester 16 is connected to the test head 12 by a flexible cable 34, and by executing an installed program, the test conditions of the wafer 32 are set, the test result is read, the test result is output, and the like.

  FIG. 2 schematically illustrates the connection state between the performance board 22 and the probe card 24. In the drawing, the second pogo tower 23 interposed between the performance board 22 and the probe card 24 is not shown. The performance board 22 is provided with seven connection points A, B, C, D, E, F, and G. The connection points A, B, C, D, E, F, and G are respectively connected to probe needles of the probe card 24 via electric circuits 35, 36, 37, 38, 39, 40, and 41 formed on the performance board 22. 25. A resistor R2 is provided in the middle of the electric circuit 35. A resistor R1 is provided in the middle of the electric circuit 38. In the middle of the electric circuit 39, a relay L1 is provided. A relay L <b> 2 is provided in the middle of the electric circuit 40. The electric circuits 35, 36, 37, 38, 39, 40, 41 and the probe card 24 are connected by the second pogo tower 23.

The semiconductor test apparatus 10 can diagnose the performance board 22 by mounting the diagnostic board 42 instead of the probe card 24. The diagnosis will be specifically described below.
FIG. 3 schematically illustrates the connection state between the performance board 22 and the diagnostic board 42. The diagnostic board 42 is formed in the same shape (equivalent dimensions) as the probe card 24. The electrical circuit 35 and the electrical circuit 36 of the performance board 22 are connected by an electrical circuit 43 formed on the diagnostic board 42. The electric circuit 37 and the electric circuit 38 are connected by an electric circuit 44 formed on the diagnostic board 42. The electric circuit 39 and the electric circuit 40 are connected by an electric circuit 45 formed on the diagnostic board 42. The electric circuit 40 and the electric circuit 41 are connected by an electric circuit 46 formed on the diagnostic board 42. The diagnostic circuit formed on the diagnostic board 42 is formed by a short circuit between the circuit of the probe card 24 and the pad when the probe needle 25 of the probe card 24 is brought into contact with the die whose pad is short-circuited. The circuit is equivalent to the circuit.
FIG. 4 is a circuit diagram illustrating a state in which the electrical circuits 37 and 38 of the performance board 22 and the electrical circuit 44 of the diagnostic board 42 described above are connected to the tester 16. The tester 16 includes a current source 50, a voltmeter 51, and electric circuits 52, 53, 54, and 55. The electrical circuit 53 grounds the connection point C of the performance board 22 in the tester 16. The current source 50 is connected to the connection point D of the performance board 22 via the electric circuit 52 and the cable 34. The current source 50 applies a predetermined amount of current to the electric circuit 52. The electric circuit 55 grounds the current source 50. The electric circuit 56 connects the voltmeter 51 to the middle of the electric circuit 52. The electric circuit 54 grounds the voltmeter 51.

When such a diagnostic board 42 is used, the quality of the resistor R1 of the performance board 22 can be diagnosed. Assuming that the current value supplied from the current source 50 is “IS”, the voltage value measured by the voltmeter is “VM”, and the resistance value of the resistor R1 is “R1”, the resistance value R1 is obtained from the following equation.
R1 = VM / IS;
Since the current value IS is known, the resistance value R1 can be obtained by measuring the voltage value VM. And the quality of resistance R1 can be diagnosed from the calculated | required resistance value R1. Further, whether or not the electric circuits 37 and 38 are disconnected or short-circuited can be diagnosed by measuring the resistance value RI.
Since the shape of the diagnostic board 42 is equivalent to that of the probe card 24, the probe card 24 and the diagnostic board 42 can be efficiently exchanged using the changer 33 of the wafer prober 14. That is, the performance board 22 can be diagnosed without removing the performance board 22 from the test head 20.
Whether or not the resistance R2 of the performance board 22 is good can be similarly diagnosed.

The circuit diagram of FIG. 5 illustrates a state in which the electrical circuits 39 and 41 of the performance board 22 and the electrical circuits 45 and 46 of the diagnostic board 42 are connected to the tester 16. The tester 16 includes a voltage source 62, a voltmeter 60, a current source 61, and electric circuits 63, 64, 65, 66, 67 and 68. The voltage source 62 is connected to the connection point E of the performance board 22 via the electric circuit 64 and the cable 34, and is grounded by the electric circuit 67. The voltmeter 60 is connected to the connection point G of the performance board 22 via the electric circuit 63 and the cable 34. The voltmeter 60 is grounded by an electric circuit 65. The electric circuit 68 connects the current source 61 and the middle of the electric circuit 63. The current source 61 is grounded by an electric circuit 66. The current source 61 allows a current having a predetermined magnitude to flow through the electric circuits 66 and 68.
When diagnosing the quality of the relay L1, a signal instructing to close the relay L1 is output from the tester 16 to the performance board 22. Then, the voltage at the connection point G of the performance board 22 is measured by the voltmeter 60. When relay L1 is securely closed, voltage value VM measured by voltmeter 60 falls within a predetermined range. For this reason, it can be determined from the voltage value VM measured by the voltmeter 60 whether or not the relay L1 is securely closed. When the relay L1 is not closed, it can be diagnosed that the relay L1 is abnormal.

  The diagnosis result of the performance board 22 is displayed on the tester 16. FIG. 6 illustrates the diagnosis result of the performance board 22 displayed on the tester 16. The confirmation result of the relay L1 executed as the test number “1” is displayed as “FAIL”. Therefore, the relay L1 is out of order. The confirmation results of the relay L2, the resistance R1, and the resistance R2 executed as the test numbers “2, 3, 4” are displayed as “PASS”. Therefore, the relay L2, the resistor R1, and the resistor R2 are normal.

When the performance board 22 is diagnosed in this way, it can be diagnosed whether or not the performance board 22 has failed. Further, when the changer 33 of the wafer prober 14 is used, the probe card 24 and the diagnostic board 42 can be exchanged without opening and closing the test head 12, so that the working efficiency is improved. Furthermore, since the performance board 22 can be diagnosed without removing the performance board 22, damage to pogo pins, positioning guides, and the like can be prevented. For this reason, the mental burden on the diagnostic operator can be reduced.
The wafer may be tested while applying thermal changes to the wafer in the wafer prober 14. In this case, the performance board 22, the second pogo tower 23, and the probe card 24 are also subjected to thermal changes. There may be a performance board 22, a second pogo tower 23, and a probe card 24 that become abnormal when exposed to a heat change even at normal temperature. Therefore, it is preferable to diagnose the performance board 22, the second pogo tower 23, and the probe card 24 while reproducing the heat change applied to the wafer. It is possible to find the performance board 22, the second pogo tower 23, and the probe card 24 that become abnormal when exposed to a heat change at normal temperature.

(Second embodiment)
The contents overlapping with those of the first embodiment will be omitted, and the characteristic part of the second embodiment will be mainly described.
As shown in FIG. 7, in this embodiment, the performance board 22 is diagnosed by connecting a diagnostic board 70 to the performance board 22 instead of the probe card 24. As shown in FIG. 8, the diagnostic board 70 includes a substrate 71 and a master die 72 mounted on the substrate 71. The substrate 71 is formed with an electric circuit 73 and has the same shape as the probe card 24. The electric circuit 73 is formed in the same manner as the electric circuit of the probe card 24. The master die 72 is a die and is packaged by drawing a conductor from a pad with which the probe needle 25 contacts. It has been confirmed that the function of the master die 72 is normal. The electric circuit 73 and the master die 72 are connected to be the same circuit as the circuit formed when the probe needle 25 of the probe card 24 is in contact with the die pad. That is, a state is created in which the semiconductor test apparatus 10 is testing the master die.

By using this diagnostic board 70, it is possible to diagnose the performance board 22, the pogo towers 21, 23, and the tester 16 (hereinafter referred to as “performance board 22 etc.”). In this case, diagnosis is performed by changing the temperature in the wafer prober 14.
FIG. 9 shows the rising characteristics of the master die 72 when power is turned on when the functions of the performance board 22 and the like are normal. The horizontal axis corresponds to the time (μs) from when power is applied, and the vertical axis corresponds to the voltage (V) measured between predetermined pins of the master die 72. When the inside of the wafer prober 14 is set to a low temperature, the master die 72 rises at T1 (μs). When the inside of the wafer prober 14 is set to room temperature, the master die 72 rises at T2 (μs). When the inside of the wafer prober 14 is set to a high temperature, the master die 72 rises at T3 (μs).
For example, when the contact resistance between the diagnostic board 70 and the second pogo tower 23 becomes large, the electrical characteristics of the performance board 22 become abnormal, or the signal output unit of the tester 16 becomes abnormal, the rising characteristics of the master die 72 Changes. FIG. 10 illustrates this state. T4, T5, and T6 are rise times of the master die 72 when the inside of the wafer prober 14 is set to low temperature, normal temperature, and high temperature, respectively, and are later than T1, T2, and T3. Thus, when the rise time of the master die 72 is greatly different from the value shown in FIG. 9, it can be diagnosed that an abnormality has occurred in the performance board 22 or the like.

  In this way, by measuring the rise time of the master die 72, it is possible to diagnose the quality of the performance board 22 and the like in a state in which the change in the characteristics of the master die 72 accompanying a change in temperature is taken into consideration. The electric element is affected by heat, and the substrate and the like are also deformed by a temperature change. Therefore, an abnormality can be found with a higher probability by making a diagnosis by changing the temperature in the wafer prober 14. Furthermore, even if an abnormality occurs in the temperature control function of the wafer prober 14, it can be discovered. The output of the master die 72 used for diagnosis is not limited to the rising characteristics. Various other electrical characteristics (eg, turn-off time, turn-on time, vibration characteristics at turn-off) can be used for diagnosis. Of course, it is also possible to make a diagnosis using the master die 72 at normal temperature without changing the temperature in the wafer prober 14.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The schematic diagram which shows the semiconductor test apparatus which concerns on 1st Example. The schematic diagram which shows the connection state of the performance board and probe card which concern on 1st Example. The schematic diagram which shows the connection state of the performance board and diagnostic board which concern on 1st Example. FIG. 3 is a circuit diagram of a performance boat and a diagnostic board according to the first embodiment. Same as above. The figure which illustrates the diagnostic result display concerning the 1st example. The schematic diagram of the state by which the diagnostic boat was mounted | worn with the semiconductor test apparatus which concerns on 2nd Example. The figure which shows the diagnostic board which concerns on 2nd Example. The figure which shows the rise time of the master die concerning a 2nd example (at the time of normal). The figure which shows the rise time of the master die which concerns on 2nd Example (at the time of abnormality).

Explanation of symbols

10: Semiconductor test equipment 12: Test head 14: Wafer prober 16: Tester 20: Test head body 21: First pogo tower 22: Performance board 23: Second pogo tower 24: Probe card 25: Probe needle 26: Hinge 30: Wafer prober Main body 31: Chuck 32: Wafer 33: Changer 34: Cables 35, 36, 37, 38, 39, 40, 41: Electric circuit 42: Diagnostic boards 43, 44, 45, 46: Electric circuit 50: Current source 51: Voltage Total 52, 53, 54, 55: Electric circuit 60: Voltmeter 61: Current source 62: Power source 63, 64, 65, 66, 67, 68: Electric circuit 70: Diagnostic board 71: Substrate 72: Master die 73: Electricity circuit

Claims (4)

Interchangeable with "is connected to the performance board, with contacting a probe needle to a pad of a die that is built into the wafer, a probe card that is interchangeable in c Ehapuroba" circuit for diagnosis of the performance board Preparing a diagnostic board on which is formed,
Replacing the diagnostic board with the probe card and connecting to the performance board;
Diagnosing the performance board by changing the temperature in the wafer prober ;
Performance board diagnostic method equipped with A wafer prober that can change the internal temperature,
Changer,
"Is connected to the performance board, with contacting a probe needle to pads are fabricated die on the wafer, a probe card that has a replaceable within said wafer prober by the changer" are interchangeable and, performance board A diagnostic board on which a diagnostic circuit is formed, and
A tester programmed with a performance board diagnostic program,
Equipped with a,
The diagnostic board diagnostic system of the performance board, characterized in Rukoto connected is conveyed in performance board by the changer. The diagnostic device according to claim 2, wherein the diagnostic circuit is a circuit equivalent to a circuit formed when a probe needle of a probe card is brought into contact with a die whose pads are short-circuited . 3. The diagnostic apparatus according to claim 2, wherein the diagnostic circuit is formed by mounting a master die on a printed board having the same dimensions as the probe card .

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