JP2007103395A - Manufacturing method of thin film device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a thin film device whose inductance is improved. <P>SOLUTION: In the manufacturing method of a thin film inductor 10, a coil 18 is formed in a groove 17 installed in a first insulating layer 16A. Thus, a clearance D1 between the coil 18 and a first magnetic layer 14A positioned on a substrate 12-side can be shortened to a desired distance by making the groove 17 deeper, and inductance in the formed thin film inductor 10 can be improved. Since an upper opening of the groove 17 spreads at the time of chamfering, a height position P1 of an upper face of Cu can easily be adjusted to a height position P2 of an edge face of the groove 17 at the time of burying Cu into the groove 17. Consequently, a second insulating layer 16B deposited on the coil 18 has high planarity. Thus, inductance can be improved much more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thin film device.

  A manufacturing method of a thin film inductor which is one of thin film devices is disclosed in, for example, Patent Document 1 below. FIG. 6 shows a cross-sectional view of the main part of the thin film inductor described in this publication. In this thin film inductor 40, an adhesion layer 44 and a first magnetic layer 46 are laminated on a substrate 42, and a first insulating film 50 in which a coil (inductance conductor) 48 is embedded is laminated thereon. A laminated structure in which a second insulating film 52 is laminated so as to cover the coil 48 exposed on the upper end surface 50 a of the first insulating film 50, and a second magnetic layer 54 is laminated on the second insulating film 52. It has become.

  As shown in FIG. 7A, the first insulating film 50 in which the coil 48 is embedded is formed by first forming the coil 48 on the temporary substrate 56 and then covering the coil 48 completely. The first insulating film 50 is laminated, and as shown in FIG. 7B, the coil 48 on the temporary substrate 56 is transferred to the substrate 42 on which the adhesion layer 44 and the first magnetic layer 46 are laminated. .

  However, the following problems exist in the manufacturing method of the thin film inductor described above. That is, if the thickness of the first insulating film 50 laminated so as to cover the coil 48 is small, the gap between the coils 48 cannot be filled with certainty. Therefore, as shown in FIG. The thickness of the insulating film 50 needs to be approximately the same as (or more than) the height of the coil 48.

  On the other hand, when the first insulating film 50 having such a thickness is laminated on the coil 48, in the thin film inductor 40 to be manufactured, the coil 48 and the first magnetic layer 46 positioned on the substrate 42 side As a result, there arises a problem that the inductance of the thin film inductor 40 is lowered.

Therefore, in order to shorten the distance D1 between the coil and the first magnetic layer, a thin film using a technique (so-called damascene process technique) for forming a coil by filling a conductor in a groove provided in the first insulating film. An inductor 60 is conceivable (see FIG. 8). That is, in the thin film inductor 60, the coil 68 is formed in the groove 67 provided in the first insulating layer 66A. Therefore, by increasing the depth of the groove 67, the coil 68 and the substrate 62 are located. The separation distance D1 from the first magnetic layer 64A can be shortened to a desired distance. That is, the coil 68 and the first magnetic layer are compared with the above-described manufacturing method in which the distance D1 between the coil 68 and the first magnetic layer 64A located on the substrate 62 side needs to be approximately the same as the height of the coil 68. The separation distance D1 from the layer 64A is shortened.
JP 2000-164426 A

  However, in the thin-film inductor 60 using the above-described damascene process technology, when the second insulating layer 66B formed on the coil 68 is not sufficiently flat, the coil coverage, device characteristics, dimensional accuracy, and post-process Therefore, the second insulating layer 66B formed on the coil 68 is required to have higher flatness and higher coverage. In particular, in a thin film device such as the above-described thin film inductor 60, the flatness of the second magnetic layer 64B formed thereon is improved by increasing the flatness of the second insulating layer 66B. The use efficiency of the magnetic permeability in the magnetic layer 64B is improved, and the inductance is improved.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a thin film device with improved inductance.

  The method of manufacturing a thin film device according to the present invention includes a first magnetic layer stacking step of stacking a first magnetic layer on a substrate, and a first groove provided with a shape corresponding to an electrode pattern on the first magnetic layer. A first insulating layer laminating step of laminating one insulating layer, a chamfering step of chamfering the edge of the groove by etching the first insulating layer, and embedding a conductor in the groove of the first insulating layer, An electrode pattern forming step for forming a pattern and a second insulating layer laminating step for laminating a second insulating layer so as to cover the groove on the first insulating layer.

  In this method for manufacturing a thin film device, an electrode pattern (for example, a coil or the like) is formed in a groove provided in the first insulating layer. Therefore, by increasing the depth of the groove, the separation distance between the electrode pattern and the first magnetic layer located on the substrate side can be shortened to a desired distance. That is, according to the method for manufacturing a thin film device according to the present invention, the conventional manufacturing method in which the distance between the electrode pattern and the first magnetic layer located on the substrate side needs to be approximately the same as the height of the electrode pattern. Compared to the above, an improvement in inductance is realized in the manufactured thin film device. In addition, in this manufacturing method, the upper opening of the groove is expanded when the edge of the groove is chamfered by the chamfering step. Therefore, the height position of the upper surface of the conductor can be easily matched with the height position of the edge surface of the groove in the electrode pattern forming step of filling the groove with the conductor. Therefore, the second insulating layer formed on the electrode pattern has high flatness, and as a result, further improvement in inductance is realized. Also, thanks to the high coverage, the electrode pattern is less likely to be oxidized under the operating environment, thereby suppressing an increase in resistance of the electrode pattern and maintaining a high inductance for a long period.

  Further, in the electrode pattern forming step, it is preferable that the conductor is buried in the groove so that the height position of the upper surface of the conductor substantially coincides with the height position of the edge surface of the groove. In this case, when the second insulating layer is stacked, the upper surface of the second insulating layer becomes sufficiently flat.

  Moreover, it is preferable to further include a second magnetic layer stacking step of stacking the second magnetic layer on the second insulating layer. In this case, a thin film inductor in which an electrode pattern is interposed between the first and second insulating layers is manufactured.

  In addition, after the second insulating layer stacking step, it is preferable to further include an insulating layer stacking step of stacking the first insulating layer on the second insulating layer, an electrode pattern forming step, and a second insulating layer stacking step. In this case, a thin film transformer in which the electrode patterns are stacked in two stages is manufactured.

  According to the present invention, a method for manufacturing a thin film device with improved inductance is provided.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments that are considered to be best for carrying out a method of manufacturing a thin film device according to the invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent element, and the description is abbreviate | omitted when description overlaps.

First, a thin film inductor 10 shown in FIGS. 1 and 2 will be described as a thin film device according to an embodiment of the present invention. As shown in these drawings, the thin film inductor 10 has a laminated structure in which a first magnetic layer 14A, a first insulating layer 16A, a second insulating layer 16B, and a second magnetic layer 14B are sequentially laminated on a substrate 12. is doing. Both the first magnetic layer 14A and the second magnetic layer 14B are made of cobalt (Co), and both the first insulating layer 16A and the second insulating layer 16B are made of silicon oxide (SiO ₂ ). Note that an insulating layer such as a SiO ₂ layer may be appropriately interposed between the substrate 12 and the first magnetic layer 14A.

  A groove 17 is provided in the first insulating layer 16A, and a planar coil (electrode pattern) 18 routed in the surface direction of the first insulating layer 16A is embedded in the groove 17. The coil 18 is formed by plating copper (Cu) on the seed layer 22 formed on the bottom surface 17 a of the groove 17. Each end 18a, 18b of the coil 18 is electrically connected to a corresponding external electrode terminal 20A, 20B formed on the surface 10a via a via (not shown) (see FIG. 1).

  Next, a procedure for manufacturing the above-described thin film inductor 10 will be described with reference to FIG.

  When the thin film inductor 10 is manufactured, as a first magnetic layer stacking step, the first magnetic layer 14A is stacked on the substrate 12 by sputtering as shown in FIG.

  Next, as a first insulating layer laminating step, a first insulating layer 16A in which a groove 17 having a shape corresponding to the shape of the coil 18 (that is, the broken line shape in FIG. 1) is provided on the first magnetic layer 14A. Laminate. Hereinafter, the procedure of the first insulating layer stacking step will be described more specifically. First, as shown in FIG. 3B, a first insulating layer 16A is laminated on the first magnetic layer 14A by CVD. Next, using a known photoresist technique, as shown in FIG. 3C, a resist mask 24 provided with an opening pattern corresponding to the drawing shape of the coil 18 is formed on the first insulating layer 16A. . Then, by performing anisotropic etching (for example, dry etching) using the resist mask 24, a groove 17 having a shape corresponding to the coiled shape of the coil 18 is formed as shown in FIG. .

  After the first insulating layer stacking step, as a chamfering step, the first insulating layer 16A is subjected to an etching process, and the edge of the groove 17 is chamfered. Then, as shown in FIG.3 (f), the upper opening of the groove | channel 17 expands gradually as it approaches the height position of an edge surface.

  Subsequently, as an electrode pattern forming step, the coil 18 is formed by filling the groove 17 of the first insulating layer 16A with Cu (conductor). Hereinafter, the procedure of this electrode pattern forming step will be described more specifically. First, as shown in FIG. 3E, the seed layer 22 is formed over the entire surface of the first insulating layer 16A using a known film formation method such as long throw sputtering with high directivity. Thereby, the seed layer 22 is also formed on the bottom surface 17 a of the groove 17. Next, by a lift-off method, as shown in FIG. 3 (f), the seed layer 22 formed other than the bottom surface 17a of the groove 17 (that is, the seed layer 22 formed on the upper surface 16a of the first insulating layer 16A). Remove. Thereafter, Cu is deposited on the seed layer 22 formed on the bottom surface 17a of the groove 17 by electrolytic plating. As a result, as shown in FIG. 3G, the first insulating layer 16A in which the groove 17 is filled with Cu and the coil 18 is buried in the groove 17 is obtained. In this way, when the coil 18 is embedded in the groove 17, the coil 18 is reliably insulated by the first insulating layer even when the coil 18 is routed close to the groove 17.

  Here, when the coil 18 is formed, since the upper opening of the groove 17 gradually expands as described above, the growth rate in the height direction of the plating gradually decreases as the height position of the edge surface of the groove 17 is approached. To do. Therefore, even if a deviation occurs in the volume of Cu to be plated, the influence of the deviation can be suppressed to a very small level. In this electrode pattern forming step, the height position P1 of the upper surface of the coil 18 to be formed and the height position P2 of the edge surface of the groove 17 (that is, the height position of the upper surface 16a of the first insulating layer 16A) are determined. Cu is filled so as to match.

  Further, as the second insulating layer stacking step, as shown in FIG. 3H, the second insulating layer 16B is stacked on the first insulating layer 16A by CVD. Thereby, the groove 17 of the first insulating layer 16A and the coil 18 embedded in the groove 17 are covered with the second insulating layer 16B. Finally, as the second magnetic layer laminating step, the second magnetic layer 14B is laminated on the second insulating layer 16B by sputtering, thereby completing the production of the thin film inductor 10 described above.

  In the method for manufacturing the thin film inductor 10 described in detail above, the coil 18 is formed in the groove 17 provided in the first insulating layer 16A. The groove 17 is provided by anisotropic etching or the like, and the depth can be easily adjusted by adjusting the etching time or the like. Therefore, by increasing the depth of the groove 17, the distance D1 between the coil 18 and the first magnetic layer 14A located on the substrate 12 side can be shortened to a desired distance (see FIG. 2).

  That is, according to the manufacturing method of the thin film inductor 10 described above, the distance D1 between the coil and the first magnetic layer needs to be approximately the same as the height of the coil (see FIGS. 6 and 6). 7), an improvement in the inductance of the manufactured thin film inductor 10 is realized.

  The thickness of the second insulating layer 16B positioned on the opposite side of the substrate 12 with respect to the coil 18 can be easily adjusted by CVD. Therefore, by laminating the second insulating layer 16B, the distance D2 between the coil 18 and the second magnetic layer 14B is shortened, and the inductance is further improved.

  In addition, in the manufacturing method of the thin film inductor 10, the chamfering of the edge of the groove 17 is performed in a chamfering process, so that the upper opening of the groove 17 gradually expands as it approaches the edge height position P2. As a result, as it approaches the height position P2 of the edge surface, the growth rate in the plating height direction gradually decreases, and even when there is a deviation in the volume of plating due to an error in plating time, etc. The effect of deviation is extremely small. That is, the height position P1 of the upper surface of Cu can be easily matched with the height position P2 of the edge surface of the groove 17 during the electrode pattern forming step. Therefore, the second insulating layer 16B formed on the electrode pattern 18 has high flatness, and the second magnetic layer 14B formed on the second insulating layer 16B also has high flatness. As a result, the inductance is further improved.

  Further, since the upper opening of the groove 17 gradually increases as it approaches the height position P2 of the edge surface, the height change between the groove 17 and the edge surface of the groove 17 is gentle. Therefore, even when the height position P1 of the upper surface of Cu does not reach the edge surface of the groove 17, sufficient step coverage is realized.

  Furthermore, since the covering property of the coil 18 is high, the coil 18 is hardly oxidized under the operating environment of the thin film inductor 10. Therefore, an increase in the resistance of the coil 18 is suppressed, and as a result, a high inductance is maintained for a long time in the thin film inductor 10.

  In addition, in the electrode pattern forming step, Cu is buried in the groove 17 so that the height position P1 of the upper surface of Cu coincides with the height position P2 of the edge surface of the groove 17, so that the second insulating layer 16B When the layers are stacked, the upper surface 16b of the second insulating layer 16B becomes sufficiently flat. When the upper surface 16b of the second insulating layer 16B is flat, the second magnetic layer 14B laminated thereon has high flatness. As a result, almost all the magnetic flux passing through the second magnetic layer 14B comes along the surface direction of the second magnetic layer 14B, and the utilization efficiency of the magnetic permeability in the second magnetic layer 14B is improved. Inductance is improved.

  Although it is possible to planarize the upper surface 16b of the second insulating layer 16B by performing a planarization process such as CMP, CMP abrasives and polishing pieces remain on the upper surface 16b, and they are removed. An adverse effect such as delamination may be considered in the subsequent process. However, if the upper surface 16b of the second insulating layer 16B is made sufficiently flat by matching the upper surface of Cu and the edge surface of the groove, such flattening processing is not necessarily required. There is no need to worry about the adverse effects of abrasives.

  Next, a thin film transformer 30 shown in FIG. 4 will be described as a thin film device according to an embodiment of the present invention. As shown in this figure, the thin film transformer 30 is a two-stage laminated structure of the thin film inductor 10 described above. That is, in the thin film transformer 30, the first magnetic layer 14A, the first insulating layer 16A, the second insulating layer 16B, the first insulating layer 16A, the second insulating layer 16B, and the second magnetic layer 14B are sequentially stacked on the substrate 12. Has a laminated structure. Although not shown in the figure, in this thin film transformer 30, the end portions 18a, 18b of the upper coil 18 and the end portions 18a, 18b of the lower coil 18 are different external electrode terminals 20A, 20B, respectively. Electrically connected.

  Next, a procedure for manufacturing the thin film transformer 30 will be described with reference to FIG.

  When manufacturing the thin film transformer 30, first, similarly to the method of manufacturing the thin film inductor 10 shown in FIG. 3, the first magnetic layer laminating step, the first insulating layer laminating step, the electrode pattern forming step, and the second insulating layer. The lamination process is performed sequentially. Then, after the second insulating layer stacking step (see FIG. 3H), as the insulating layer stacking step, the first insulating layer 16A provided with the grooves 17 is stacked on the second insulating layer 16B, and further chamfered. As a process, as shown in FIG. 5A, the first insulating layer 16A is etched and the edge of the groove 17 is chamfered. Further, as shown in FIG. 5B, the coil 18 is formed as an electrode pattern forming step, and as shown in FIG. 5C, the second insulating layer 16B is formed on the first insulating layer 16A as shown in FIG. 5C. Are stacked. Finally, as the second magnetic layer stacking step, the second magnetic layer 14B is stacked on the second insulating layer 16B, thereby completing the above-described production of the thin film transformer 30.

  According to the method of manufacturing the thin film transformer 30, the distance D1 between the coil 18 and the first magnetic layer 14A located on the substrate 12 side is shortened to a desired distance, as in the method of manufacturing the thin film inductor 10 described above. Therefore, the inductance of the thin film transformer 30 to be manufactured can be improved. In addition, the second insulating layer 16B is thinly laminated, or Cu is embedded in the groove 17 so that the height position P1 of the upper surface of Cu coincides with the height position P2 of the edge surface of the groove 17, Improvement of inductance is realized.

  Further, in the method of manufacturing the thin film transformer 30, the chamfering of the edge of the groove 17 is performed in the chamfering process as in the method of manufacturing the thin film inductor 10 described above. The height position P1 of the upper surface can be easily adjusted to the height position P2 of the edge surface of the groove 17. Therefore, the second insulating layer 16B formed on the electrode pattern 18 has high flatness, and the second magnetic layer 14B formed on the second insulating layer 16B also has high flatness. As a result, the inductance is further improved.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, each magnetic layer is not limited to sputtering, and can be laminated using other known lamination methods. Moreover, each insulating layer can be laminated | stacked using not only CVD but another well-known lamination | stacking method. Each insulating layer may be composed of an inorganic insulating material other than SiO _2, it may be further configured with an organic insulating material such as polyimide. Note that a spin coating method can be used for film formation of the organic insulator. For forming the grooves, isotropic etching, laser processing, or the like can be used in addition to anisotropic etching. Further, as a method for chamfering the groove, there is a method in which sputter ions are incident from a direction shifted by a predetermined angle from the normal direction of the substrate.

It is the top view which showed the thin film inductor which concerns on embodiment of this invention. It is the II-II sectional view taken on the line of the thin film inductor shown in FIG. It is the figure which showed the procedure which produces the thin film inductor shown in FIG. It is principal part sectional drawing which showed the thin film transformer which concerns on embodiment of this invention. It is the figure which showed the procedure which produces the thin film inductor shown in FIG. It is principal part sectional drawing which showed the thin film inductor which concerns on a prior art. It is the figure which showed the procedure which produces the thin film inductor shown in FIG. It is principal part sectional drawing which showed the thin film inductor which concerns on a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 40, 60 ... Thin film inductor, 12, 62 ... Board | substrate, 14A, 64A ... 1st magnetic layer, 14B, 64B ... 2nd magnetic layer, 16A, 66A ... 1st insulating layer, 16B, 66B ... 2nd insulating layer , 17, 67... Groove, 18, 68... Coil, 30.

Claims (4)

On the board
A first magnetic layer laminating step of laminating the first magnetic layer;
A first insulating layer laminating step of laminating a first insulating layer provided with a groove having a shape corresponding to an electrode pattern on the first magnetic layer;
A chamfering step of chamfering the edge of the groove by etching the first insulating layer;
An electrode pattern forming step of forming an electrode pattern by filling a conductor in the groove of the first insulating layer;
A method of manufacturing a thin film device, comprising: a second insulating layer stacking step of stacking a second insulating layer on the first insulating layer so as to cover the groove.   2. The thin film according to claim 1, wherein, in the electrode pattern forming step, the conductor is embedded in the groove so that a height position of an upper surface of the conductor substantially coincides with a height position of an edge surface of the groove. Device manufacturing method.   The method of manufacturing a thin film device according to claim 1, further comprising a second magnetic layer stacking step of stacking a second magnetic layer on the second insulating layer.   After the second insulating layer laminating step, further comprising an insulating layer laminating step of laminating the first insulating layer on the second insulating layer, the electrode pattern forming step, and the second insulating layer laminating step. The manufacturing method of the thin film device of Claim 1 or 2.

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