JPS6269545A - Spiral inductor - Google Patents

Abstract

PURPOSE:To flatten the providing part of an intersected taking-out conductor and to prevent the occurrence of wire breakdown, at on intersecting part where the conductor is taken out of the inner terminal of a winding part, by providing a recess part in a semiconductor substrate, and burying a winding-part conductor in then recess part. CONSTITUTION:In the surface of a semiconductor substrate 1 at an intersecting part of a winding-part conductor 2 and a taking-out part conductor 3, a groove 5 is formed. In the groove 5, the winding-part conductor 2 is buried and an insulating layer 4 is buried on the conductor 2. The surface of the insulating layer 4 substantially agrees with the surface of the substrate 1. Therefore, a step part is not yielded on the taking-out conductor 3, which is formed on the layer 4, and wire breakdown and the increase in resistance are avoided. When the groove 5 is made shallow and the insulating layer 4 is made thick, the stray capacitance between the winding-part conductor 2 and the taking-out part conductor can be reduced with flatness being maintained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a semiconductor circuit device in which a semiconductor substrate-F
- This relates to an ultra-high frequency spiral inductor formed in an IC.

[Conventional technology]

@4 Figure (a) A is a plan view showing an example of the configuration of a conventional spiral inductor, and Figure (b) is an enlarged sectional view taken along line 19'B---B in Figure (a). In the figure, fil is a semiconductor substrate, (2) is a winding part conductor, and (3) is a winding part conductor (a cross-takeout part conductor for taking out the inner end of 21 to the outside, 14).
An insulating layer made of a polyimide resin with a low dielectric constant or an insulating semiconductor is used to insulate the winding part conductor (2) and the leading part conductor (3) at the intersection of the lamp.

The spiral inductor as shown in FIGS. 4(a) and 4(b) is manufactured by depositing metal on the entire surface of the semiconductor substrate
Fine pattern lines created by light exposure method! At this time, it is necessary to insulate between the wire conductor (3) and the winding conductor (21) with a low dielectric constant insulating layer (4). , the conductor width is several tm to 10fim, the conductor metal thickness is around several meters, and the absolute RFRI+) thickness is around lm. Therefore, it is necessary to wire the signal surface exposed part conductor (3) over a height difference equal to the sum of the thickness of the winding part conductor (2) and the thickness of the insulating layer (41).

[Problem that the invention seeks to solve]

4th F4 In the conventional spiral inductor configuration as shown in (a) and (b), the microscopic structure is created by exceeding the step of the sum of the thickness of the winding conductor (2) and the thickness of the insulating layer 141 thereon. Therefore, for example, the thickness of the winding part conductor (2) may be increased to reduce the skin resistance, or the winding part conductor (3) and the winding part conductor (2) may be made thicker to reduce the skin resistance. To reduce the stray capacitance between the insulating layer (4) and
Furthermore, when the number of spiral turns is increased to 1, there is a problem that the level difference becomes large, which may cause disconnection of the lead-out conductor (3) or increase in line resistance.

This invention was made to solve the above problems.
To obtain a spiral inductor 'J&-, which does not produce a step part in a cross-takeout conductor taken out from an inner end of a winding part to the outside, and is free from wire breakage and increase in line resistance.

[Means for solving problem rIII] In the spiral inductor according to the present invention, a concave portion is provided in the semiconductor substrate where the winding part conductor and the insulating layer thereon are provided at the intersection of the winding part conductor and the take-out part conductor. The surface of the semiconductor substrate and the top surface of the insulating layer are substantially flush with each other.

[Effect]

In the spiral inductor of this invention, at the intersection of the winding part conductor and the take-out part conductor, the winding part conductor and the insulating layer thereon are provided on the semiconductor substrate, and the surface through which the IC embedding part conductor passes is flattened. Therefore, wire breakage and increase in line resistance can be avoided.

〔Example〕

Figures 1(a) and 1(b) and (c) are plan views showing the configuration of a spiral inductor according to an embodiment of the present invention.
471.1 The TB-IB line in Figure (a) and ■
a- (A cross-sectional view taken along line a, with the same symbol Ji+ as in the conventional example described above.
Show equivalent parts and avoid duplication of explanation. In the figure,
(A group-shaped groove formed on the surface of the semiconductor substrate (1) at the intersection of the winding part conductor (21) and the take-out part conductor (3). 4) is buried in this groove (5), and the upper surface of the insulating layer (4) substantially coincides with the surface of the semiconductor substrate f11.Therefore, the lead-out conductor 131 tl formed thereon
j There is no difference in level, and wire breakage and increase in resistance can be avoided. The group-shaped grooves (6) are further deepened to form the insulating layer 14.
) is made thicker to maintain flatness while increasing the conductor of the 1st winding +21
& ff Stray capacitance between it and the protruding conductor (3)? Can be made smaller.

Figures 2 and 3 are cross-sectional views showing the structure of the conductor intersections of another embodiment of the present invention and an embodiment of Vuko Shin's IC, respectively. 6) can be replaced with a two-step groove (6) as in the embodiment shown in Fig. 2, a round groove (6), and an inverted triangular cross-section groove (6) as in the embodiment shown in Fig. 3.
A similar effect can be obtained by using 7).

[Effects of the Invention] As explained above, in the spiral inductor according to the present invention, the recess f is formed in the semiconductor substrate at the intersection where the conductor is taken out from the inner terminal of the winding part to the outside. Since the insulating layer is embedded in the concave portion, the 2111 portion of the cross-output conductor can be flattened, and occurrence of disconnection and increase in resistance can be prevented. Furthermore, by increasing the thickness of the insulating layer while maintaining the above effects, the stray capacitance at the intersection can be reduced.

[Brief explanation of drawings]

Fig. 1(a) n A plan view showing the configuration of a spiral inductor according to an embodiment of the present invention, Fig. 1(b) and (c)
)fj sohzo-hfFJ1 Enlarged sectional view taken along the IB-IB line and lo-70 line in Figure (a), Figures 2 and 3
411 of this invention! FIG. 4 (al.
Structure of conventional spiral inductor 1i112. ? Plan view shown in Fig. 4(b) ij gK4 (■ in all
It is an enlarged cross-sectional view taken along the line B-■B. In the figure, (11 semiconductor substrates, (2) winding part conductors, (3) take-out part conductors, +411/'i insulating layer, (
6) Concave part (group groove), (6) has four parts (two-step groove), +71 light four parts (groove with inverted triangular cross section). Note that in the figure, the minus sign Ji+ indicates a portion corresponding to the same straddle.

Claims (1)

[Claims] (1) A device having a planar winding portion formed on a semiconductor substrate and a take-out portion that intersects the conductor of the winding portion three-dimensionally in order to take out the inner end of the winding portion to the outside. The winding portion conductor at the crossing portion and an insulating layer provided thereon to insulate between the conductor at the take-out portion are embedded in a recess formed on the surface of the semiconductor substrate, and the upper surface of the insulating layer and the semiconductor A spiral inductor characterized in that the surface of a substrate is substantially flush with the surface of a substrate.