JP5604918B2 - Evaluation element and evaluation method - Google Patents

Description

The present invention relates to an evaluation element and an evaluation method .

  In the manufacturing process of a semiconductor device, charge-up during a plasma process such as film formation using a plasma CVD (Chemical Vapor Deposition) method is a problem. When a charge is charged in the wiring or the like, the charge may be discharged through a gate insulating film electrically connected to the wiring, for example. As a result, the gate insulating film is destroyed. As an element for evaluating damage due to charge-up, an evaluation element is known which is formed on a semiconductor substrate without using a gate insulating film and includes wiring layers facing each other with the insulating film interposed therebetween (for example, Patent Document 1).

JP 2007-180207 A

  However, in the case where the gate insulating film is not used, the insulating film is not easily destroyed by the charged up charge. Therefore, the sensitivity for detecting the charged-up charge is low, and the area of the antenna electrode is increased. For this reason, the area of an evaluation element will become large.

The purpose of the evaluation element and the evaluation method is to improve the sensitivity of detecting the charged up charge.

For example, an insulating film formed on a semiconductor substrate, a first wiring including an extending portion formed in the insulating film, extending in the extending direction and electrically connected to the first pad, and in the insulating film A contact provided to electrically connect the semiconductor substrate and the extending portion, and formed in the insulating film, facing the surface direction of the extending portion and the semiconductor substrate and shorter in length than the extending portion. a counter portion, and the lead portions led out in the opposite direction of the first wiring from the opposed portion, and an antenna electrode that is electrically connected to the second wiring and the lead-out portion and the second pad including a look-containing An evaluation element is used that evaluates the charge-up to the antenna electrode when the insulating film is formed by measuring conduction between the first pad and the second pad .

According to the evaluation element and the evaluation method , it is possible to improve the sensitivity for detecting the charged up charge.

FIG. 1 is a top view of the evaluation element according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a cross-sectional view of the evaluation element during the process. FIG. 4 is a plan view of the vicinity of the first wiring and the second wiring of the evaluation element according to the second embodiment. FIG. 5A to FIG. 5C are schematic cross-sectional views of the evaluation element according to Example 2. FIG. FIG. 6 is a plan view illustrating an example of dimensions of the first wiring and the second wiring. FIG. 7 is a plan view illustrating an example in which the evaluation element according to Example 2 is formed between pads.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a top view of the evaluation element according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. As shown in FIGS. 1 and 2, the evaluation element 100 includes a semiconductor substrate 10, an insulating film 14, a first wiring 20, a second wiring 30, and an antenna electrode 40. The insulating film 14 is formed on the semiconductor substrate 10. The first wiring 20 is provided in the insulating film 14 and includes an extending portion 22 and a lead portion 24. The extending part 22 extends in the extending direction. The extending portion 22 and the semiconductor substrate 10 are electrically connected by a contact 26 (for example, a contact hole filled with metal) provided in the insulating film 14. The lead portion 24 electrically connects the extending portion 22 and the pad 60. A highly doped region 12 is formed in the semiconductor substrate 10. The highly doped region 12 is, for example, a P-type region formed in the P well and has a higher doping concentration than the P well.

  The second wiring 30 is provided in the insulating film 14 and includes a facing portion 32 and a lead portion 34. The facing portion 32 extends in the extending direction of the extending portion 22 and faces the extending portion 22 in the surface direction of the semiconductor substrate 10. The extending portion 22 and the facing portion 32 are separated by a gap G. The space between the extending portion 22 and the facing portion 32 is filled with the insulating film 14. Further, the length L2 of the facing portion 32 is shorter than the length L1 of the extending portion 22. The lead portion 34 is drawn from at least one of both ends of the facing portion 32 in the direction opposite to the first wiring 20. The first wiring 20 and the second wiring 30 are formed by the same wiring layer M1. The antenna electrode 40 is connected to the lead portion 34. The antenna electrode 40 is formed in a meander shape. The antenna electrode 40 is connected to the pad 70. The pad 60 includes a pad electrode 62a and a pad electrode 62b, and a contact 64 that connects the pad electrode 62a and the pad electrode 62b. The pad 70 includes a pad electrode 72a and a pad electrode 72b, and a contact 74 that connects the pad electrode 72a and the pad electrode 72b. The pad electrode 62a and the pad electrode 72a are formed of the same wiring layer M1 as the first wiring 20 and the second wiring 30. The pad electrode 62b and the pad electrode 72b are formed of the same wiring layer M2.

  FIG. 3 is a cross-sectional view of the evaluation element during the process. As shown in FIG. 3, a wiring layer M1 including the first wiring 20, the second wiring 30, and the antenna electrode 40 is formed in the uppermost layer. When an insulating film is further formed thereon using the CVD method, the antenna electrode 40 is charged up. Since the antenna electrode 40 and the second wiring 30 are electrically connected, the antenna electrode 40 and the second wiring 30 have the same potential. On the other hand, the first wiring 20 is connected to the semiconductor substrate 10 through a contact 26. Therefore, the first wiring 20 has a constant potential such as ground. When the antenna electrode 40 has a large amount of charge, dielectric breakdown occurs between the facing portion 32 and the extending portion 22. Thereby, the opposing part 32 and the extending | stretching part 22 short-circuit. Semiconductor device manufacturing Conductivity between pads 60 and 70 is measured during or after the wafer process. Thereby, it is possible to evaluate the charge-up of the antenna electrode caused by the plasma process in the wafer process.

  In order to cause a short circuit between the facing portion 32 and the extending portion 22, the length L <b> 2 of the facing portion 32 is shortened by the length L <b> 1 of the extending portion 22. Thereby, an electric field concentrates between the opposing part 32 and the extending | stretching part 22, and it becomes easy to produce a dielectric breakdown. Further, the extending portion 22 and the semiconductor substrate 10 are connected by a contact 26. Thereby, the inductance between the extending portion 22 and the semiconductor substrate 10 can be reduced. Therefore, dielectric breakdown between the facing portion 32 and the extending portion 22 is likely to occur. In order to reduce the inductance component, it is preferable that the extending portion 22 and the semiconductor substrate 10 are directly connected by the contact 26.

  As shown in FIG. 1, a plurality of contacts 26 are preferably provided in the extending direction. Thereby, the inductance between the extending | stretching part 22 and the semiconductor substrate 10 can be made small, and resistance can be made small. Therefore, dielectric breakdown between the facing portion 32 and the extending portion 22 is likely to occur.

  Furthermore, it is preferable to provide the highly doped region 12 that is electrically connected to the plurality of contacts 26 and provided in the semiconductor substrate 10, extending in the extending direction and having a higher doping concentration than the semiconductor substrate 10. Thereby, the resistance between the extending portion 22 and the semiconductor substrate 10 can be reduced. Therefore, dielectric breakdown between the facing portion 32 and the extending portion 22 is likely to occur. The highly doped region 12 is preferably not provided under the facing portion 32. The semiconductor substrate 10 may be a P-well as in the first embodiment. Further, the semiconductor substrate 10 (or well) and the highly doped region may be N-type.

  The drawer portion 34 is preferably pulled out from at least one of both ends of the facing portion 32. According to an experiment in which the shape of the second wiring 30 is changed, in such a crank structure, dielectric breakdown is likely to occur between the end of the facing portion 32 (the corner of the crank structure) and the extending portion 22. Therefore, the detection sensitivity can be further improved by pulling out the pull-out portion 34 from the end of the facing portion 32. Furthermore, it is preferable that the drawing portion 34 is drawn from both ends of the facing portion 32. Further, the antenna electrode 40 can be connected to the lead portions 34 drawn from both sides of the facing portion 32. Further, the common antenna electrode 40 can be connected to the lead-out portions 34 drawn from both sides of the facing portion 32.

  In order to increase the antenna ratio, it is preferable to increase the area of the antenna electrode 40. When the antenna electrode 40 is on a line and has a meander shape, the antenna electrode 40 can be formed in the gap between the chips. The antenna electrode 40 may be flat, for example. The pads 60 and 70 may be connected to the first wiring 20 and the antenna electrode 40, respectively. When the antenna ratio is the ratio of the area of the antenna electrode 40 to the area of the facing portion 32, the antenna ratio is preferably 3000 or more.

  As the semiconductor substrate 10, for example, a silicon substrate can be used. As the insulating film 14, for example, a film mainly containing silicon oxide or a low-k insulating film having a dielectric constant smaller than that of the silicon oxide film can be used. As the first wiring 20, the second wiring 30, and the antenna electrode 40, for example, a metal mainly containing Al or Cu can be used. As the metal for embedding the contact, for example, a metal mainly containing Cu or W can be used.

  Example 2 is an example in which an antenna electrode is formed by a plurality of wiring layers having a multilayer wiring structure. FIG. 4 is a plan view of the vicinity of the first wiring and the second wiring of the evaluation element according to the second embodiment. FIG. 5A to FIG. 5C are schematic cross-sectional views of the evaluation element according to Example 2. FIG. As shown in FIG. 4, a plurality of second wirings 30 are provided to face the extending portion 22. The lead portions 34 of the plurality of second wirings 30 are connected to the plurality of contact portions 50, respectively. The plurality of contact portions 50 are connected to the plurality of antenna electrodes 40, respectively. The antenna electrodes 42a to 42f of the wiring layers M1 to M6 of the multilayer wiring are connected to the contact portion 50 via connection wirings 56a to 56f, respectively.

  FIG. 5A is a schematic diagram showing the second wiring 30 connected to the antenna electrode 42a of the lowermost wiring layer M1 in the multilayer wiring. As shown in FIG. 5A, multilayer wiring layers M1 to M6 are stacked with an insulating film 14 interposed therebetween. The antenna electrodes 42a to 42f of the multilayer wiring layers M1 to M6 are provided so as to overlap each other. In the contact portion 50, the electrodes 52a to 52f of the multilayer wiring layers M1 to M6 are provided so as to overlap each other. In the pad 60, the pad electrodes 62a to 62f of the multilayer wiring layers M1 to M6 are provided so as to overlap each other. The pad electrodes 62a to 62f are electrically connected by contacts 64a to 64e, respectively. In the pad 70, pad electrodes 72a to 72f of the multilayer wiring layers M1 to M6 are provided so as to overlap each other. The pad electrodes 72a to 72f are electrically connected by contacts 74a to 74e, respectively.

  The first wiring 20 and the second wiring 30 are formed by the lowermost wiring layer M1. The antenna electrode 42a and the electrode 52a of the lowermost wiring layer M1 are connected by a connection wiring 56a of the wiring layer M1. The antenna electrode 42a and the pad electrode 72a are connected by a connection wiring 76a of the wiring layer M1.

  As described above, the short circuit between the first wiring 20 and the second wiring 30 can be evaluated by evaluating the continuity between the pad 60 and the pad 70, and the insulating film is formed on the wiring layer M1. Plasma damage can be evaluated.

  FIG. 5B is a schematic diagram showing the second wiring 30 connected to the antenna electrode 42c of the wiring layer M3 in the multilayer wiring. As shown in FIG. 5B, in the contact portion 50, the electrodes 52a to 52c are electrically connected by contacts 54a and 54b, respectively. The antenna electrode 42c and the electrode 52c of the wiring layer M3 are connected by the connection wiring 56c of the wiring layer M3. The antenna electrode 42c and the pad electrode 72c are connected by a connection wiring 76c of the wiring layer M3.

  By evaluating the continuity between the pad 60 and the pad 70 as described above, a short circuit between the first wiring 20 and the second wiring 30 can be evaluated, and an insulating film is formed on the wiring layer M3. Plasma damage can be evaluated.

  FIG. 5C is a schematic diagram showing the second wiring 30 connected to the antenna electrode 42f of the uppermost wiring layer M6 among the multilayer wiring. As shown in FIG. 5C, in the contact portion 50, the electrodes 52a to 52f are electrically connected by contacts 54a to 54e, respectively. The antenna electrode 42f and the electrode 52f of the wiring layer M6 are connected by a connection wiring 56f of the wiring layer M6. The antenna electrode 42f and the pad electrode 72f are connected by a connection wiring 76f of the wiring layer M6.

  By evaluating the continuity between the pad 60 and the pad 70 as described above, a short circuit between the first wiring 20 and the second wiring 30 can be evaluated, and an insulating film is formed on the wiring layer M6. Plasma damage can be evaluated.

  FIG. 6 is a plan view illustrating an example of dimensions of the first wiring 20 and the second wiring 30. The space | interval of the extending | stretching part 22 and the opposing part 32 is 0.24 micrometer, for example. The width W1 of the first wiring 20 and the second wiring 30 is, for example, 0.32 μm, and the length L3 of the lead portion 24 of the first wiring 20 is, for example, 1.5 μm. The length L2 of the extending portion 22 is, for example, 66 μm, the length L2 of the second wiring 30 facing portion 32 is, for example, 1.5 μm, and the length L4 of the lead portion 34 is, for example, 1.2 μm. A distance P between the second wiring connected to the adjacent wiring layer is, for example, 10.56 μm. The width W2 of the highly doped region 12 is, for example, 0.5 μm.

  FIG. 7 is a plan view illustrating an example in which the evaluation element according to Example 2 is formed between pads. A pad 60 is electrically connected to the first wiring 20. Details of the second wiring 30 are not shown. As the pads 70, corresponding pads 70a to 70f of the wiring layers M1 to M6 are provided. The antenna electrode 40 is laminated so that the antenna electrodes 42a to 42f overlap as shown in FIGS. The antenna electrode 40 is provided between the pads and outside the pads. Between the pads, the antenna electrode 40 is even formed in a meander shape to ensure the length. The pads 70a to 70f are connected to the antenna electrodes 42a to 42f using connection wirings 76a to 76f, respectively. Thus, by detecting whether the pads 70a to 70f and the pad 60 are short-circuited, the influence of charging on the antenna electrodes 42a to 42f can be investigated.

  According to the second embodiment, as shown in FIGS. 5A to 5C, the plurality of antenna electrodes 40 are formed of the plurality of wiring layers M1 to M6 stacked on the semiconductor substrate 10 with the insulating film 14 interposed therebetween. It corresponds to. As shown in FIG. 4, the plurality of second wirings 30 are electrically connected to the plurality of antenna electrodes 42a to 42f, respectively. As a result, it is possible to evaluate the charge-up from the antenna electrodes 42a to 42f caused by the plasma treatment performed on the wiring layers M1 to M6.

  Further, it is preferable that the facing portions 32 of the plurality of second wirings 30 are arranged in the extending direction of the extending portion 22. Thereby, the evaluation element for evaluating the charge-up in the plurality of wiring layers M1 to M6 can be reduced in size.

  Furthermore, it is preferable that the lengths of the facing portions 32 of the plurality of second wirings 30 are the same. Moreover, it is preferable that the distance of each opposing part 32 of the some 2nd wiring 30 and the extending | stretching part 22 is the same. Thereby, the charge-up amount at which the first wiring 20 and the second wiring 30 are short-circuited can be made the same.

  Further, the first wiring 20 and the plurality of second wirings 30 are formed by the lowermost wiring layer M1 among the plurality of wiring layers M1 to M6. Thereby, the inductance between the 1st wiring 20 and the semiconductor substrate 10 can be made small, and resistance can be made small. Therefore, dielectric breakdown between the first wiring 20 and the second wiring 30 is likely to occur.

  Further, as shown in FIGS. 5A to 5C, the plurality of antenna electrodes 42a to 42f overlap in the stacking direction of the plurality of wiring layers M1 to M6. Thereby, the area which arrange | positions the antenna electrodes 42a and 42f can be reduced. By making the areas of the antenna electrodes 42a and 42f substantially the same, it is possible to compare the charge-up amounts between the wiring layers M1 to M6.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

The following appendices are further disclosed with respect to the embodiments including Examples 1-2.
(Supplementary Note 1) An insulating film formed on a semiconductor substrate, a first wiring including an extending portion formed in the insulating film and extending in an extending direction, provided in the insulating film, the semiconductor substrate and the A contact for electrically connecting the extending portion; and an opposing portion formed in the insulating film, facing the extending portion and a surface direction of the semiconductor substrate and having a shorter length than the extending portion; An evaluation element comprising: a second wiring including a lead portion that is led out in a direction opposite to the first wiring; and an antenna electrode that is electrically connected to the lead portion.
(Supplementary note 2) The evaluation element according to supplementary note 1, wherein a plurality of the contacts are provided in the extending direction.
(Supplementary note 3) Supplementary note 2 comprising a highly doped region electrically connected to the plurality of contacts, provided in the semiconductor substrate, extending in the extending direction and having a higher doping concentration than the semiconductor substrate. The evaluation element as described.
(Appendix 4) The evaluation element according to any one of appendices 1 to 3, wherein the lead-out portion is drawn out from at least one of both ends of the facing portion.
(Supplementary Note 5) A plurality of the antenna electrodes and the second wirings are provided, and the plurality of antenna electrodes correspond to a plurality of wiring layers stacked via an insulating film on the semiconductor substrate, and a plurality of the second wirings are provided. The evaluation element according to any one of appendices 1 to 4, wherein the wiring is electrically connected to each of the plurality of antenna electrodes.
(Additional remark 6) The said opposing part of each of these 2nd wiring is arranged in the said extending | stretching direction, The evaluation element of Additional remark 5 characterized by the above-mentioned.
(Supplementary note 7) The evaluation element according to supplementary note 5 or 6, wherein the first wiring and the plurality of second wirings are formed by a lowermost wiring layer of the plurality of wiring layers.
(Supplementary note 8) The evaluation element according to any one of supplementary notes 5 to 7, wherein the plurality of antenna electrodes overlap in a stacking direction of the plurality of wiring layers.

DESCRIPTION OF SYMBOLS 10 Semiconductor substrate 12 Highly doped area | region 14 Insulating film 20 1st wiring 22 Extending part 26 Contact 30 2nd wiring 32 Opposing part 34 Leading part 40 Antenna electrode

Claims (6)

An insulating film formed on the semiconductor substrate;
A first wiring including an extending portion formed in the insulating film, extending in the extending direction, and electrically connected to the first pad ;
A contact provided in the insulating film and electrically connecting the semiconductor substrate and the extending portion;
A facing portion formed in the insulating film, facing the extending portion in the surface direction of the semiconductor substrate and having a length shorter than the extending portion, and a leading portion drawn from the facing portion in the opposite direction of the first wiring And a second wiring including
An antenna electrode electrically connected to the lead portion and the second pad ;
Seen including,
The evaluation element characterized by evaluating the charge-up to the said antenna electrode at the time of forming the said insulating film by measuring conduction | electrical_connection between the said 1st pad and the said 2nd pad .   The evaluation element according to claim 1, wherein a plurality of the contacts are provided in the extending direction.   3. The evaluation according to claim 2, further comprising a highly doped region electrically connected to the plurality of contacts, provided in the semiconductor substrate, extending in the extending direction and having a higher doping concentration than the semiconductor substrate. element.   The evaluation element according to claim 1, wherein the lead-out portion is drawn out from at least one of both ends of the facing portion. A plurality of the antenna electrode and the second wiring are provided,
The plurality of antenna electrodes correspond to a plurality of wiring layers stacked on the semiconductor substrate via an insulating film,
The evaluation element according to claim 1, wherein the plurality of second wirings are electrically connected to the plurality of antenna electrodes, respectively. An insulating film formed on the semiconductor substrate;
A first wiring including an extending portion formed in the insulating film, extending in the extending direction, and electrically connected to the first pad;
A contact provided in the insulating film and electrically connecting the semiconductor substrate and the extending portion;
A facing portion formed in the insulating film, facing the extending portion in the surface direction of the semiconductor substrate and having a length shorter than the extending portion, and a leading portion drawn from the facing portion in the opposite direction of the first wiring And a second wiring including
An antenna electrode electrically connected to the lead portion and the second pad;
Using an evaluation element including
An evaluation method comprising: evaluating charge-up to the antenna electrode when the insulating film is formed by measuring conduction between the first pad and the second pad.

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