JP2007024719A - Evaluation method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize measurement and heighten measurement efficiency by reducing a measurement fault caused by a contact failure of a probe. <P>SOLUTION: This method has the first pad group 7a connected to an evaluation element 2 on a semiconductor substrate 1, and the second pad group 7b connected to a conductor 5 for contact check. Before measurement of the evaluation element, the probe is brought beforehand into contact with the second pad group, and a resistance is measured by applying a voltage between adjacent pads, to thereby confirm whether probe-pad contact is normal or not. Then, when the probe-pad contact is normal, the probe is brought into contact with the first pad group, to thereby perform characteristic measurement of the evaluation element. When the probe-pad contact is abnormal, the probe is cleaned, or a contact condition of the probe is changed, and then it is confirmed again whether the probe-pad contact is normal or not. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device evaluation method for stabilizing measurement and improving measurement efficiency when evaluating a semiconductor process or the like.

  In a conventional method for evaluating a semiconductor device, a pad necessary for applying a potential or current is connected to an evaluation target TEG (Test Element Group), and a probe is contacted with the pad. Then, a potential is applied to the probe from the measuring instrument, and the potential or current set by the measuring instrument is applied to the evaluation target TEG for evaluation.

  However, an insulator may remain on the pad due to process abnormality or process variation during TEG manufacturing. In this case, the conduction between the pad and the probe becomes unstable, and as a result, a predetermined potential or current cannot be applied to the evaluation target TEG, and the evaluation may not be possible.

  Therefore, when a continuity failure between the pad and the probe occurs, the evaluation is not interrupted by using a preliminarily arranged spare pad connected to the evaluation target TEG, and a measurement abnormality is caused. The evaluation can be continued efficiently without causing it (for example, Patent Document 1).

Next, a conventional method for evaluating a semiconductor device will be described with reference to FIG. As shown in FIG. 5, the potential or current necessary for evaluating the evaluation element 12 via the contact plug 14 is applied to the evaluation element (TEG) 12 formed on the interlayer insulating film 13 on the semiconductor substrate 11. A plurality of pad openings 17 opened in the protective film 16 are provided for the conductor 15 to be added. A probe 18 capable of contacting all the pad openings 17 is provided. A probe changeover switch 19 is attached to each probe 18. When this TEG 12 is evaluated, a pad that can be applied with the same potential as that of the pad that has become defective in conduction is selected by switching the switch 19 of the probe 18 to avoid measurement abnormality.
JP 7-245330 A

  However, in the above-described conventional technology, it is necessary to analyze from the characteristics of the TEG in order to identify a place where there is a pad abnormality or a probe abnormality and select a spare pad. Therefore, as a premise for evaluation, it is essential that the TEG to be evaluated always exhibits normal and expected characteristics. However, in the TEG evaluation, it is necessary to evaluate the influence of process condition fluctuations and process variations, and the TEG does not always operate normally. For this reason, even if a measurement abnormality occurs during measurement, it is difficult to distinguish whether it is caused by TEG, probe or pad abnormality.

  Therefore, in the TEG measurement, the measurement is continued in a situation where a measurement abnormality has occurred, and after analyzing the measurement result, the probing condition is changed and remeasured. However, this conventional technique cannot be applied to cases where re-measurement causes characteristic fluctuations such as reliability evaluation.

  Accordingly, an object of the present invention is made in view of the above problems, and before applying a potential or current to a TEG to be evaluated, a contact abnormality between the pad and the probe, which is a measurement abnormality, is detected in advance, and the pad and the probe are detected. An object of the present invention is to provide a method for evaluating a semiconductor device for evaluating electrical characteristics, which can stabilize measurement and increase measurement efficiency by starting evaluation after avoiding abnormalities.

  In order to solve the above-described problem, a semiconductor device evaluation method according to claim 1 of the present invention includes an evaluation element formed on a semiconductor substrate, a first pad group connected to the evaluation element, and the semiconductor A method for evaluating a semiconductor device comprising a contact check conductor formed on a substrate and a second pad group connected to the contact check conductor, before measuring the evaluation element, A probe-pad contact confirmation step for confirming whether or not the probe-pad contact is normal by contacting a probe with the second pad group in advance and applying a voltage between adjacent pads to measure resistance; An evaluation element characteristic measuring step of performing a characteristic inspection of the evaluation element by contacting a probe to one pad group, and the probe-pad contact confirmation process When the probe-pad contact is normal, the evaluation element characteristic measurement step is performed after the probe-pad contact confirmation step, and the probe-pad contact is abnormal in the probe-pad contact confirmation step. After performing the cleaning of the probe or changing the contact condition of the probe, after performing the step of repeatedly performing the probe-pad contact confirmation step until the probe-pad contact becomes normal, the evaluation element characteristics Perform the measurement process.

  The semiconductor device evaluation method according to claim 2 is the semiconductor device evaluation method according to claim 1, wherein the arrangement of the first pad group and the arrangement of the second pad group are the same.

  According to the semiconductor device evaluation method of the present invention, the evaluation element formed on the semiconductor substrate, the first pad group connected to the evaluation element, and the contact check formed on the semiconductor substrate A probe device including a probe-pad contact confirmation step and an evaluation element characteristic measurement step in a semiconductor device comprising a conductive conductor and a second pad group connected to the contact check conductor, the probe-pad contact confirmation step When the probe-pad contact is normal, the evaluation element characteristic measurement step is performed after the probe-pad contact confirmation step. When the probe-pad contact is abnormal in the probe-pad contact confirmation step, the probe is cleaned. Or change the probe contact conditions, After the process of repeatedly performing the probe-pad contact confirmation process until the normal operation is completed, the evaluation element characteristic measurement process is performed, and after a series of measurements are completed as before, the TEG analysis is performed and then remeasured. Thus, it is possible to prevent the delay of the measurement result feedback and the decrease in the operating rate of the measuring instrument, and to stabilize the measurement and increase the measurement efficiency.

  According to the second aspect, since the arrangement of the first pad group and the arrangement of the second pad group are the same, the first pad group connected to the evaluation element when a pad abnormality occurs during the manufacture of the semiconductor device. Since this also occurs in the second pad group of the contact check pattern, the contact abnormality detection efficiency between the pad and the probe is improved.

  A first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a diagram showing a main part plan layout of a semiconductor device according to the first embodiment of the present invention, and FIG. 2 shows a main part cross-sectional layout of the semiconductor device according to the first embodiment of the present invention. FIG.

  As shown in FIG. 2, this semiconductor device is formed on the semiconductor substrate 1, an evaluation element 2 formed on the semiconductor substrate 1, a first pad group (pad opening) 7 a connected to the evaluation element, and the semiconductor substrate 1. The contact check conductor 5 and a second pad group (pad opening) 7 b connected to the contact check conductor 5 are provided.

  In this case, as shown in FIG. 1, in the semiconductor device of this embodiment, the pad openings 7 are arranged in a line. This arrangement is the same in both the contact check pattern and the evaluation element (TEG) portion described below.

  Next, as shown in FIG. 2A, in the pad portion of the contact check pattern of the semiconductor device of this embodiment, an interlayer insulating film 3 is formed on the semiconductor substrate 1, and a conductor 5 is formed on the interlayer insulating film 3. Is formed. Furthermore, a protective film 6 and a pad opening 7 b from which the protective film 6 has been removed are formed on the conductor 5.

  The pad portion of this contact check pattern is formed on the interlayer insulating film 3 including the interlayer insulating film 3 formed on the semiconductor substrate 1, the conductor 5 formed on a predetermined portion on the interlayer insulating film 3, and the conductive film 5. After the protective film 6 is formed, the part of the protective film corresponding to the pad opening 7b is removed.

  Next, as shown in FIG. 2B, in the evaluation element portion of the semiconductor device of this embodiment, the evaluation element 2 is formed on the semiconductor substrate 1, and the interlayer insulating film 3 is formed on the evaluation element 2. Yes. Further, a conductive film 5 electrically connected to the evaluation element 2 through the contact plug 4 is formed on the interlayer insulating film 3, and the protective film 6 and the protective film 6 are removed on the conductor 5. A pad opening 7a is formed.

  In the pad portion of the evaluation element portion, after the evaluation element 2 is formed on the semiconductor substrate 1, the interlayer insulating film 3 is formed, a predetermined portion in the interlayer insulating film 3 is opened, and a conductor is embedded in the opening portion. After forming a contact plug 4 and forming a conductor 5 in a predetermined portion on the interlayer insulating film 3 including the contact plug, and further forming a protective film 6 on the interlayer insulating film 3 including the conductive film 5, a pad opening is formed. It can be manufactured by removing the insulating film corresponding to the portion 7a.

  Next, an evaluation method of the evaluation element 2 using such a semiconductor device will be described below.

  First, before measuring the evaluation element 2, the probe-pad contact is normal by contacting the probe in advance to the pad opening 7b of the contact check pattern provided in the vicinity and applying a voltage between adjacent pads to measure the resistance. Check whether or not.

  Next, when the probe-pad contact is normal, the measurement is started by contacting the probe 8 to the pad opening 7 connected to the evaluation element 2. On the other hand, if the probe-pad contact is abnormal, contact conditions such as probe cleaning, probe position, and probe-pad pressure are changed, and the contact is rechecked using the contact check pattern. This recheck is repeated while changing the conditions as necessary until the probe-pad contact becomes normal. When the probe-pad contact becomes normal, the probe 8 is contacted to the pad opening 7a connected to the evaluation element 2 and measured. To start.

  One embodiment will be described in more detail below with reference to FIGS. 3 and 4.

  FIG. 3 is a main part plan layout diagram of an example of the semiconductor device according to the first embodiment of the present invention, and FIG. 4 is a diagram showing a measurement flow when this example is used.

  As shown in FIG. 3, the conductor material for forming the contact check pattern is Cu, and the size of the Cu wiring is 120 μm wide and 11000 μm long. After growing an insulating film on the Cu wiring, the pad portion is etched to provide ten pad openings 7 on the conductor at a pitch of 120 μm. The pad opening size is 70 μm.

  With respect to the measurement flow, as shown in FIG. 4, before the actual evaluation pattern is measured, cleaning is performed in order to remove deposits on the probe tip (S1). The probe tip is cleaned by contacting the probe five times on a cleaning sheet coated with an adhesive material, and the attached matter on the probe tip moves to the cleaning sheet.

  Thereafter, the probe contact check pattern pad is probed (S2). Probing is performed with overdrive so that the probe contacts 70 μm deeper than the contact between the probe and the pad so that the oxide film on the contact pad surface does not cause contact abnormality.

  Next, a voltage of 1 mV is applied between the adjacent first pad 1 and second pad (S3), and the current flowing between the pads is monitored. This measurement is performed between all the pads, such as between the second pad and the third pad (S4).

  If there is no abnormality in the measurement state, the resistance between adjacent pads is about 1Ω, so the current value monitored between the pads is 1 mA. When all the inter-pad resistances become normal, that is, when a current of 1 mA or more and 2 mA or less is monitored, it is determined that normal measurement is possible (S5), and probing is performed on the pads connected to the pattern to be originally evaluated. Then, measurement is started (S6).

  On the other hand, if the resistance between adjacent pads shows a partial abnormality in S5, that is, if a current of 1 mA or less is monitored, the probe tip cleaning is performed again, and then the probing contact check pattern pad is used. And repeat the measurement for contact check.

  In the above description, the contact check before the start of measurement is shown as an example. However, more stable measurement is possible by probing on the pad of the probing contact check pattern during the measurement after the start of measurement and incorporating the check.

  By using such a semiconductor device evaluation method, it is possible to prevent a delay in measurement result feedback and a decrease in the operating rate of the measuring instrument, such as a re-measurement after a TEG analysis is performed after a series of measurements is completed. And measurement efficiency can be improved.

  In addition, by making the pad structure of the contact check pattern between the pad and the probe installed in advance the same structure as the pad structure connected to the evaluation element section, if a pad abnormality occurs during the manufacture of the semiconductor device, it is connected to the evaluation element. Since this also occurs in the pad of the contact check pattern in the same manner as the formed pad, the detection efficiency of the contact abnormality between the pad and the probe is improved.

  In the above-described embodiment, the semiconductor device has been described with respect to the case where the pad openings 7 are arranged in a line. However, the present invention is not limited to this shape, and an optimum configuration according to the arrangement and shape of the evaluation elements. A multi-row configuration may be used, and the overall shape is not limited to a rectangle, and may be a square or other shapes.

  The method for evaluating a semiconductor device according to the present invention can detect a measurement abnormality caused by a probe-pad contact failure before measuring an evaluation element, and stabilizes measurement when evaluating a semiconductor process or the like. In addition, it is useful for a semiconductor device evaluation method for improving measurement efficiency.

It is explanatory drawing which shows the planar layout of the semiconductor device by the 1st Embodiment of this invention. (A) is sectional drawing of the contact check pattern of the semiconductor device by the 1st Embodiment of this invention, (b) is sectional drawing of an evaluation element part. It is explanatory drawing which shows the planar layout of the semiconductor device of one Example of this invention. It is explanatory drawing which shows the measurement flow of one Example of this invention. It is explanatory drawing which shows the outline | summary of the conventional semiconductor device.

Explanation of symbols

1 Semiconductor substrate 2 Evaluation element (TEG)
3 Interlayer insulating film 4 Contact plug 5 Conductor 6 Protective film 7 Pad opening 8 Probe 11 Semiconductor substrate 12 Element 13 Interlayer insulating film 14 Contact 15 Conductor 16 Insulator 17 Pad 18 Probe 19 Probe switching switch

Claims (2)

An evaluation element formed on a semiconductor substrate, a first pad group connected to the evaluation element, a contact check conductor formed on the semiconductor substrate, and a contact check conductor A method for evaluating a semiconductor device comprising a second pad group,
Prior to measuring the evaluation element, a probe is contacted in advance with the second pad group, and a resistance is measured by applying a voltage between adjacent pads, thereby checking whether the probe-pad contact is normal or not. -Pad contact confirmation process;
An evaluation element characteristic measuring step of performing a characteristic inspection of the evaluation element by contacting a probe to the first pad group,
In the probe-pad contact confirmation step, when the probe-pad contact is normal, the evaluation element characteristic measurement step is performed after the probe-pad contact confirmation step,
In the probe-pad contact confirmation step, when the probe-pad contact is abnormal, the probe is cleaned until the probe-pad contact becomes normal after cleaning the probe or changing the probe contact condition. A method for evaluating a semiconductor device, wherein the evaluation element characteristic measurement step is performed after the step of repeatedly performing the pad contact confirmation step.   The semiconductor device evaluation method according to claim 1, wherein an arrangement of the first pad group and an arrangement of the second pad group are the same.

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