JP2006038791A - Prober needle switching device, prober device and method for measuring semiconductor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems wherein a discrete device needs, particularly for measurement of an element having a reverse electrode, an extended moving time of a prober device for completing tests to all elements on a wafer and an extended time for contact of prober needles, which deteriorate the efficiency, since each element is probed and measured one by one, and a simultaneous measurement by a conventional technique needs a large cost because it needs a plurality of testers responding to a plurality of measuring elements. <P>SOLUTION: A measurement is performed by bringing a plurality of prober needles into contact with a plurality of elements, and successively switching measuring elements by a measuring element switching means. According to this, the moving time of the prober device and the time necessary for contact of the prober needles can be shortened, and the efficiency can be raised. Since measurements for a plurality of elements is performed by use of one tester, reduction in cost of the prover device and space saving of the prober device are attained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a prober needle switching device, a prober device, and a semiconductor element measuring method, and more particularly to a prober needle switching device, a prober device, and a semiconductor element measuring method for measuring a discrete element having a back electrode.

  In recent years, for the purpose of shortening the time required for the wafer probing test, the same measurement process has been performed in which a plurality of elements are simultaneously measured. FIG. 9 shows a conventional probing test method. FIG. 9 is a basic schematic diagram of a semiconductor test apparatus that performs the same measurement.

  As shown in the figure, the semiconductor test apparatus includes a test processor 40 that controls the entire apparatus, a logic pattern generation unit 41 that generates a test signal, and a plurality of tester units 44 corresponding to individual elements that perform the same measurement. Has been.

The logic pattern generation unit 41 that has received the start signal from the test processor 40 generates a test signal and an expected value signal, sends the test signal to the register group of the pulse pattern generation unit 45 of the tester unit 44, and the register of the logic comparison unit 48. The expected value signal is transmitted to each group. The test signal output from the pulse pattern generation unit 45 is given to a DUT (Device Under Test) 60 via a driver 46. The response signal output from the DUT 60 is given to the logic comparison unit 48 via the comparator 47. The logical comparison unit 48 logically compares the test result from the comparator 47 with the expected value signal from the logical pattern generation unit 41, detects a match / mismatch, and determines whether the DUT 60 is good or bad. The operation of the semiconductor test apparatus is simultaneously performed on a plurality of tester units 44 corresponding to individual elements. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 2001-84156 (Item 12, FIG. 8)

  However, since a conventional semiconductor test apparatus for performing the same measurement for a plurality of elements needs to include a plurality of tester units corresponding to the individual elements, the size of the semiconductor test apparatus is increased as the diameter of the wafer advances. There has been a problem that it increases in proportion to the size and requires a large amount of cost.

  In addition, when measurement is performed using a conventional semiconductor test apparatus, there is a possibility that the measurement time of each element is different as the measurement progresses, and the test items are shifted. In an element such as an LSI in which the potential of the substrate does not vary, a test signal can be simultaneously applied to a plurality of elements even in such a case.

  On the other hand, since an element whose substrate potential varies is tested in a wafer state, a common measurement signal is transmitted to the back electrode during measurement. Therefore, if a difference occurs in the measurement time of each element and the test item is shifted, different signals are applied to adjacent elements, affecting the potential of each element, and accurate measurement of each element cannot be performed. .

  Therefore, in order to perform the same measurement of an element having a back electrode with a discrete device, a plurality of tester units corresponding to each measurement element are synchronized for each test item so that the test items of each measurement element are not shifted and interfere with each other. There is a need.

  However, even if each test item is synchronized with the above multiple testers, if one of the measuring elements has a short circuit between the drain and source or a short circuit between the drain and gate, All the elements are short-circuited.

  For the above reasons, in order to accurately measure an element having a back electrode with a discrete device, the prober needle is brought into contact with only one element, and when the measurement is completed, the prober needle is separated from the element, and the stage is moved to the next measurement. It was necessary to move to the element for measurement.

  Therefore, there is a problem that the stage moving time required for completing the test for a large number of elements formed on the wafer becomes long and the efficiency is low.

The present invention has been made in view of such problems, and a plurality of prober needles that collectively contact a plurality of discrete elements on a semiconductor wafer and individually correspond to the elements,
It comprises measuring element switching means for connecting to the prober needle and sequentially switching the plurality of prober needles to measure the elements individually.

  The measuring element switching means is prepared corresponding to the plurality of elements, and is configured by a relay circuit that receives a switching signal from the outside and switches the plurality of prober needles. .

  The relay circuit is a mercury relay circuit.

A plurality of prober needles that collectively contact a plurality of discrete elements on the semiconductor wafer and individually correspond to the elements;
One tester for measuring the element by transmitting a measurement signal to the prober needle;
A prober controller for transmitting a measurement start signal to the tester;
And a measuring element switching means connected to the tester and the prober needle and sequentially switching the plurality of prober needles to measure the elements individually.

  The measuring element switching means is prepared corresponding to the plurality of elements, and is configured by a relay circuit that receives a switching signal from the outside and switches the plurality of prober needles. .

  Further, a plurality of prober needles individually corresponding to a plurality of discrete elements on the semiconductor wafer are brought into contact with the plurality of elements at a time, and one set of prober needles is selected from the plurality of prober needles. The plurality of elements are sequentially measured by measuring the elements and switching the prober needle.

A step of bringing a plurality of prober needles individually corresponding to a plurality of discrete elements on a semiconductor wafer into contact with the plurality of elements at once;
Selecting a set of prober needles for measuring one of the elements by means of measuring element switching means connected to the plurality of prober needles;
Transmitting a measurement signal from a tester and measuring the one element;
Switching the prober needle by the measuring element switching means;
It is characterized by comprising.

  Further, the measuring element switching means is constituted by a relay circuit, and the relay circuit is sequentially switched by an element selection signal transmitted by a prober control unit.

  The relay circuit performs four-terminal measurement of the element.

  The switching time of the measuring element switching means is 20 ms or less.

  According to the present invention, firstly, in the conventional measurement method, the measurement is performed by moving the prober needle every time one element is measured, so that the movement time from the element to the element is about 200 ms, The prober needle switching device of the present invention performs measurement by switching a prober needle by a plurality of prober needles corresponding to a plurality of elements and making contact in a lump and a measuring element switching means. The switching time is about 5 ms, which can be reduced to about 40 times that of the conventional measurement method.

  Secondly, since the measuring element switching means is a relay circuit that can be attached and detached on the prober needle switching device, a complicated change of wiring on the board is not required by changing the number of measuring elements, and by removing and attaching the relay circuit It is possible to easily change the number of elements to be switched.

  Third, since the relay circuit corresponding to a plurality of elements is a mercury relay, chattering does not occur when the relay is switched, and stable measurement can be performed.

  In addition, the relay contact portion is a completely encapsulated contact, and measurement with high reliability can be performed.

  In addition, wear at the time of contact with the relay is small, and multiple measurements are possible.

  Fourthly, the prober device includes a prober needle switching device, and the measurement can be performed with a single tester for a plurality of measurement elements by performing measurement by switching the prober needle. Therefore, it is possible to reduce the cost for the prober device and to save the space for the prober device.

  Fifth, the prober needle contacts a plurality of elements at a time, but since the measurement is performed by selecting one set of prober needles for one element, an element having a back electrode, particularly a discrete device, It becomes possible to measure accurately without being influenced by the potential of the adjacent element.

  Sixth, since each element is measured by four-terminal measurement, accurate measurement can be performed without including the wiring resistance and the contact resistance between the prober needle and the measuring element.

  Embodiments of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a block diagram showing a system configuration of the prober apparatus. As shown in the figure, the prober device 14 of the present embodiment includes a prober needle switching device 3, a tester 2, a prober control unit 1, and a HEADBOX 4.

  The prober needle switching device 3 includes a plurality of prober needles that collectively contact a plurality of discrete elements on a semiconductor wafer and individually correspond to the elements, and sequentially switch the plurality of prober needles to measure the elements individually. . Details will be described later.

  The tester 2 outputs an END signal for completing the measurement, a measurement result, and the like to the prober control unit 1.

  The prober control unit 1 outputs a START signal for starting measurement to the tester 2. Further, the prober control unit 1 has a stage 19 on which the wafer 6 to be measured is placed, and moves the stage 19.

  The HEADBOX 4 has a function of detecting a minute current and performing measurement with high accuracy and suppressing oscillation generated during the measurement.

  The prober control unit 1 and the tester 2 are connected by an I / F cable 5. The prober needle switching device 3 and the prober control unit 1 are connected by an I / F cable 5. The prober needle switching device 3 has a measuring element switching means 39 (described later), and its drive power is supplied from the prober control unit 1 or the tester 2.

  The prober needle switching device 3 and the HEADBOX 4, the HEADBOX 4 and the stage 19, and the HEADBOX 4 and the tester 2 are connected by an analog cable 7.

  FIG. 2 shows details of the prober needle switching device 3. FIG. 2A is a plan view showing the prober needle switching device 3. As shown in the figure, the prober needle switching device 3 includes a measuring element switching means 39, a prober control unit connection unit 36, a probing card 35, a probing card connection unit 33, and a HEADBOX connection unit 32.

  The measuring element switching means 39 is a relay circuit which is prepared corresponding to a plurality of elements, acquires a switching signal from the outside, and switches a plurality of prober needles, and includes a plurality of relay units 9 installed on the substrate. Is done.

  The relay unit 9 is prepared corresponding to the number of measurement elements to be switched by the relay circuit. Therefore, when the number of measuring elements is changed, it is necessary to prepare the relay unit 9 accordingly. However, since the relay unit 9 can be removed, the relay unit 9 can be easily changed by simply removing the relay unit 9 without changing the configuration of the wiring 30 in a complicated manner in accordance with the change in the number of measurement elements.

  The probing card 35 includes a probe unit 34 having a plurality of prober needles for contacting the electrode pads of the plurality of measuring elements. Details will be described later. Further, the probing card 35 can be attached to and detached from the substrate 31. Therefore, measurement of elements with different electrode pad positions, measurement with different numbers of measurement elements, and the like can be flexibly handled by simply replacing the probing card 35.

  A measurement signal, a measurement value, and the like are transmitted to the measurement element and the HEADBOX connection unit 32 via the wiring 30. For example, the measurement element selection signal is transmitted from the prober control unit connection unit 36 to the relay unit 9 via the wiring 30.

  FIG. 2B is an enlarged plan view of a part of the back surface of the probing card 35. As shown in the figure, the probe portion 34 that contacts the measuring element is connected to the substrate connecting portion 38.

  In the present embodiment, the measurement element is described as a MOSFET having a back electrode. In the present embodiment, four-terminal measurement that is not affected by wiring resistance or contact resistance is employed as a measurement method. For this reason, a probe portion composed of four prober needles corresponds to one element. Specifically, the probe portion 34a corresponding to the element 8a has four prober needles 15, 16, 17, and 18, and the prober needles 15 and 16 come into contact with the gate electrode pad 26 of the element 8a, and the source electrode pad. The prober needles 17, 18 come into contact with 27. A plurality of probe units 34 are provided corresponding to the elements 8 to be measured, and contact the corresponding elements 8 as described above. Then, a set of probe units 34a that perform measurement is selected by a measurement element selection signal input from the outside, and the corresponding element 8a is measured. When the measurement of one element 8a is completed, the probe unit 34a is switched to select the probe unit 34b, and the corresponding element 8b is measured. As described above, according to the present embodiment, the plurality of probe units 34 are collectively brought into contact with the plurality of elements 8, and the corresponding elements can be individually measured by sequentially switching and selecting the probe units 34.

  In order to prevent a short circuit due to contact between the prober needles of the probe unit 34 and to prevent a shift in the measurement position of each prober needle, the prober needle is fixed by an insulator 37.

  The board connection portion 38 has a connection pin to the prober needle switching device 3 (not shown) on the front side, and the connection pin is connected to the back surface of the probing card connection portion 33.

  FIG. 3 is a circuit schematic diagram of the prober needle switching device 3 provided with the measuring element switching means 39.

  Each prober needle in contact with the gate electrode pad 26 and the source electrode pad 27 of the element 8a is connected to the relay portion 9a. And by connecting the relay 10, 11, 12, 13 of the relay part 9a, in addition to applying a voltage to the element 8a, the measurement result of the element 8a is acquired.

  The relay circuit of the relay unit 9 uses a mercury relay characterized by no chattering. Therefore, stable measurement can be performed. In addition, although the mercury relay was used in this embodiment, you may use the dry relay characterized by connecting in a short time.

  FIG. 4 is a diagram showing the flow of measurement signals and power.

  First, a START signal is transmitted from the prober control unit 1 to the tester 2. The tester 2 measures one element and checks the measurement element for defects. Then, an END signal is transmitted to the prober control unit 1 simultaneously with the measurement result.

  The prober control unit 1 transmits an element selection signal to the prober needle switching device 3 using the END signal as a trigger. Upon receiving the element selection signal, the prober switching device 3 switches the relay unit 9 to the next measuring element.

  By using the prober device 14 as described above, it is possible to perform measurement with a single tester for a plurality of measurement elements, and thus it is possible to save space and reduce the cost of the prober device. In addition, since the measurement is performed by switching the prober needle by the plurality of prober needles corresponding to the plurality of elements and the measurement element switching means, the wafer measurement time can be shortened.

  Next, the semiconductor element measurement method of this embodiment will be described with reference to FIGS.

  In the semiconductor element measuring method of this embodiment, a plurality of discrete elements on a semiconductor wafer and a plurality of prober needles respectively corresponding to the plurality of prober needles are brought into contact with the plurality of elements at a time, and one set of prober needles among the plurality of prober needles One of the elements is measured by selecting a needle, and the plurality of elements are sequentially measured by switching the prober needle.

  FIG. 5 is a flowchart of the measuring operation using the measuring element switching means 39. FIG. 6 is a timing chart of the measuring operation using the measuring element switching means 39.

  The first step is a step of bringing a plurality of discrete elements on the semiconductor wafer and a plurality of prober needles individually corresponding to the plurality of elements together (step S1). In the present embodiment, the elements that can be measured at once by the prober needle switching device 3 are an element group composed of eight elements.

  The stage 19 in the prober control unit 1 is moved upward, and a plurality of probe parts 34a, 34b,..., 34h of the prober needle switching device 3 corresponding to the elements 8a, 8b,. To make each element measurable. At this time, the two wirings provided on the stage 19 are in contact with the drain electrode 25 on the back surface of the wafer 6, that is, are connected to all the elements (see FIG. 3).

  The second step is a step of selecting one set of prober needles for measuring one of the elements by the measuring element switching means connected to the plurality of prober needles (step S2).

  The prober control unit 1 sets the element selection signal 1 to LO in order to select one set of prober needles for measuring elements first, and one set of prober needles 15, 16, 17, and 18 are selected and corresponding to them. The element 8a to be measured can be measured (see a in FIG. 6).

  The third step is a step of transmitting a measurement signal from the tester and measuring the one element (step S3).

  After the element 8a becomes measurable, the tester 2 transmits power to the prober needle switching device 3 via the HEADBOX 4 in response to a START signal (see b in FIG. 6) from the prober control unit 1, and a plurality of signals are transmitted to the element 8a. Measure the electrical characteristics. The tester 2 generates a PASS signal when the measured value is within the set arbitrary value range, and generates a FAIL signal when the measured value is out of the range.

  The fourth step is a step of switching the prober needle by the measuring element switching means (Yes in step S4).

  The tester 2 transmits an END signal and a PASS / FAIL signal as a measurement result to the prober control unit 1 (see c and d in FIG. 6). The measurement result is stored in a memory built in the prober control unit 1.

  At the same time, the prober control unit 1 transmits an element selection signal to the prober needle switching device 3 using the END signal as a trigger. Upon receiving the element selection signal, the prober switching device 3 receives the element selection signal, selects a set of prober needles for measuring the element, and puts the element 8b into a measurable state. At this time, the element selection signal 1 becomes HI (non-selected state) (see e in FIG. 6).

  Thus, by switching the probe unit 9, the switching time from element to element can be set to 3 ms to 10 ms. In this embodiment, 5 ms is adopted. That is, the time from the end of measurement of one element to the start of measurement of the next element is 5 ms.

  When the above operation is repeated and the measurement of all the elements in contact with the plurality of probe units of the prober needle switching device 3 is completed (No in step S4), the prober control unit 1 moves the stage 19 downward, 8 and the probe 34 are separated (step S5). If there are still unmeasured elements (Yes in step S6), the stage 19 is moved (step S7), and the probe unit 34 is then brought into contact with the element group to be measured for measurement.

  The above operation is repeated to measure all elements on the wafer 6 (No in step S6). Further, the defective element marking process is performed collectively after the measurement of all the elements on the wafer 6 is completed based on the measurement result stored in the prober control unit 1 (after marking).

  In this embodiment, the number of elements that can be switched by the prober needle switching device 3 is an element group of 8 units, but the number of elements constituting the element group may be changed as necessary.

  In the present embodiment, an example of specific measurement will be described with reference to FIGS. In this embodiment, the tester 2 measures a plurality of electrical characteristics.

  FIG. 7 is a circuit diagram for measuring VDS (ON). As shown in the figure, the tester 2 includes a constant current source 21 and a constant voltage source 22, and the constant current source 21 is connected to the drain and the constant voltage source 22 is connected to the gate. The prober needle switching device 3 includes eight relay units 9a, 9b,..., 9h corresponding to the number of measurement units.

  First, before the measurement of the element, the stage 19 (see FIG. 1) is moved upward, and the element 8a and the like, the plurality of probe portions 34a of the prober needle switching device 3 corresponding to each element, etc. )) Is brought into contact so that each element can be measured.

  The prober needle switching device 3 receives the measurement element selection signal from the prober control unit 1, and transmits the relays 10 and 11 of the relay unit 9a to the gate electrode pad 26 of the element 8a, and the relays 12 and 13 to the source electrode pad 27. Connect to the circuit that passes to

  In response to the START signal from the prober control unit 1, the tester 2 applies a voltage to the gate electrode and causes a current to flow from the drain electrode. Then, the voltage value between the drain and source of the element 8a is measured via the HEADBOX 4. The tester 2 generates a PASS signal when the measured voltage value is within the range of the set arbitrary voltage value, and generates a FAIL signal when it is outside the range.

  Subsequently, BVDSS is measured for the same measuring element.

  FIG. 8 is a circuit diagram for measuring BVDSS. As shown, the tester 2 includes a constant current source 21 and is connected to the drain.

  The measurement is performed in a state where the gate electrode and the source electrode are connected by the switch 23 in the tester 2 and further connected to the GND by the switch 24.

  In addition to the above electrical characteristics, measurements such as VGS (OFF) and IDSS are performed, and when all the electrical characteristics are measured, the tester 2 sends the PASS / FAIL signal to the prober control unit 1 simultaneously with the END signal. Send. The prober control unit 1 stores the PASS / FAIL signal in a memory built in the prober control unit 1.

  Upon receiving the element selection signal from the prober control unit 1, the prober needle switching device 3 releases the relay unit 9a connected to the probe unit 34a and connects the relay unit 9b to the probe unit 34b of the element 8b which is the next measuring element. To do.

  When the above operation is repeated and measurement of all elements in contact with the probe unit 34 of the prober needle switching device 3 is completed, the prober control unit 1 moves the stage 19 downward, and then the element group to be measured. Move up.

  Then, the stage 19 is again moved upward, and the probe 34 is brought into contact with the measuring element to perform measurement.

  When the above operations are repeated and measurement of all elements on the wafer 6 is completed, after-marking is performed based on the PASS / FAIL signal of each element stored in the prober control unit 1, and the measurement is completed.

  Actually, the measurement time for one wafer was calculated.

  As a result, in the conventional measuring method, the stage is moved each time one element is measured, and the measurement is performed by moving the stage from the element to the element. On the other hand, in the measuring method of the present invention, the prober needle is used. Is contacted in advance with the element group, and switching is performed by the relay unit 9, so that the switching time from the element to the element becomes about 5 ms. It was confirmed that the time to start was shortened to about 1/40.

  In addition, the measurement time for one wafer is about 120 minutes in the conventional measurement method, and is about 80 minutes in the measurement method of the present invention. Thus, according to the measurement method of the present invention, the measurement time can be shortened to about two thirds compared with the conventional measurement method.

It is a block diagram explaining the prober apparatus of this invention. It is a top view explaining the prober needle switching device of the present invention. It is a circuit schematic diagram explaining the prober needle | hook switching apparatus and semiconductor element measuring method of this invention. It is a figure explaining the semiconductor element measuring method of this invention. It is a flowchart explaining the semiconductor element measuring method of this invention. It is a timing chart figure explaining the semiconductor device measuring method of the present invention. It is a circuit diagram explaining the measuring method of VDS (ON) of this invention. It is a circuit diagram explaining the measuring method of BVDSS of this invention. It is a schematic diagram explaining the conventional prober apparatus and the probing method.

Explanation of symbols

1 prober control unit 2 tester 3 prober needle switching device 4 HEADBOX
5 I / F cable 6 Wafer 7 Analog cable 8, 8a, 8b, ... Element 9, 9a, 9b, ... Relay part 10, 11, 12, 13 Relay 14 Prober device 15, 16, 17, 18 Prober Needle 19 Stage 21 Constant current source 22 Constant voltage source 23, 24 Switch 25 Drain electrode 26 Gate electrode pad 27 Source electrode pad 30 Wiring 31 Substrate 32 HEADBOX connection part 33 Probing card connection part 34, 34a, 34b, ... Probe part 35 probing card 36 prober control unit connection unit 37 insulator 38 substrate connection unit 39 measuring element switching means 40 test processor 41 logic pattern generation unit 44 tester unit 45 pulse pattern generation unit 46 driver 47 comparator 48 logic comparison unit 60 DUT (Dev ce Under Test)

Claims (12)

A plurality of prober needles that collectively contact a plurality of discrete elements on a semiconductor wafer and individually correspond to the elements;
A prober needle switching device, comprising: a measuring element switching means connected to the prober needle and sequentially switching the plurality of prober needles to measure the elements individually.   2. The measuring element switching means is prepared corresponding to the plurality of elements, and is configured by a relay circuit that receives a switching signal from the outside and switches the plurality of prober needles. Prober needle switching device.   The prober needle switching device according to claim 2, wherein the relay circuit is a mercury relay circuit. A plurality of prober needles that collectively contact a plurality of discrete elements on a semiconductor wafer and individually correspond to the elements;
One tester for measuring the element by transmitting at least a measurement signal to the prober needle;
A prober controller that transmits at least a measurement start signal to the tester;
A prober apparatus comprising: a measuring element switching means connected to the tester and the prober needle, and sequentially switching the plurality of prober needles to measure the elements individually.   5. The measurement element switching means is prepared corresponding to the plurality of elements, and comprises a relay circuit that receives a switching signal from the outside and switches the plurality of prober needles. Prober equipment.   6. The prober device according to claim 5, wherein the relay circuit is a mercury relay circuit.   A plurality of discrete elements on the semiconductor wafer and a plurality of prober needles individually corresponding to the plurality of prober needles are collectively brought into contact with the plurality of elements, and one set of prober needles is selected from the plurality of prober needles. A method of measuring a semiconductor element, comprising: measuring and sequentially measuring the plurality of elements by switching the prober needle. A step of bringing a plurality of prober needles individually corresponding to a plurality of discrete elements on a semiconductor wafer into contact with the plurality of elements at once;
Selecting a set of prober needles for measuring one of the elements by means of measuring element switching means connected to the plurality of prober needles;
Transmitting a measurement signal from a tester and measuring the one element;
Switching the prober needle by the measuring element switching means;
A method for measuring a semiconductor element, comprising:   9. The semiconductor element measuring method according to claim 8, wherein the measuring element switching means is constituted by a relay circuit, and the relay circuit is sequentially switched by an element selection signal transmitted by a prober control unit.   The semiconductor element measuring method according to claim 9, wherein the relay circuit is a mercury relay circuit.   The semiconductor element measurement method according to claim 9, wherein the relay circuit performs four-terminal measurement of the element.   The semiconductor element measuring method according to claim 9, wherein a switching time of the measuring element switching means is 20 ms or less.

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