JP2016081958A - Manufacturing method of thin film metal resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of manufacturing a plurality of thin film metal resistances having values of resistance per unit length different from each other while suppressing an increase in the number of manufacturing processes.SOLUTION: A method includes the steps of: forming a resist pattern 41 having a first opening 42 for forming a first thin film metal resistor and a second opening 43 for forming a second thin film metal resistor on an insulation film 51; depositing a metal material for a thin film metal resistance within the first opening 42 and the second opening 43 on the resist pattern 41; and removing the metal material on the resist pattern 41 by removing the resist pattern 41. The width W5 of a first part 42a of the first opening 42 for forming a first resistance part of the first thin film metal resistor is made narrower than the width W6 of a first part 43a of the second opening 43 for forming a second resistance part of the second thin film metal resistor.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing a thin film metal resistor.

  Patent Document 1 describes an electronic device having a resistance film made of a metal thin film. In this electronic device, the resistive film has two or more types of resistivity. These two or more resistivities are realized by partially oxidizing the metal thin film to increase the resistance, and changing the length of the oxidized portion in accordance with the resistivity.

JP2011-040497A

  When an electronic device is manufactured on a semiconductor wafer, a plurality of thin film metal resistors having different resistance values per unit length may be manufactured on the wafer for high integration. In such a case, for example, the length of the oxidized portion of the metal thin film may be varied as in the electronic device described in Patent Document 1, but a process for oxidizing the metal thin film is required, and the number of manufacturing steps increases. Resulting in. Moreover, if the thin film metal resistor having a high resistance value and the thin film metal resistor having a low resistance value are manufactured by different processes, the number of manufacturing steps is also increased.

  An object of the present invention is to provide a method capable of producing a plurality of thin film metal resistors having different resistance values per unit length while suppressing an increase in the number of manufacturing steps.

  A method of manufacturing a thin film metal resistor according to an embodiment of the present invention includes a first thin film metal resistor including a first resistor and a second resistor having a lower resistance value per unit length than the first resistor. A method for producing a second thin film metal resistor on an insulator, the first opening for forming a first thin film metal resistor, and the second opening for forming a second thin film metal resistor A resist pattern forming process for forming a resist pattern on the insulator, a metal deposition process for depositing a metal material for a thin film metal resistor on the resist pattern, in the first opening, and in the second opening, and a resist pattern And a lift-off process for removing the metal material on the resist pattern, and in the resist pattern forming process, the width of the first opening for forming the first resistance part is formed to form the second resistance part. First Narrower than the width of the opening portion.

  According to the present invention, it is possible to produce a plurality of thin film metal resistors having different resistance values per unit length while suppressing an increase in the number of manufacturing steps.

FIG. 1 is a diagram illustrating an example of a thin film metal resistor manufactured by a manufacturing method according to an embodiment. Fig.1 (a) is a top view which shows the structure of a 1st thin film metal resistor, FIG.1 (b) is a sectional side view along the II line | wire of Fig.1 (a). FIG. 2 is a diagram illustrating an example of a thin film metal resistor manufactured by a manufacturing method according to an embodiment. FIG. 2B is a plan view showing the configuration of the second thin film metal resistor, and FIG. 2B is a side sectional view taken along the line II-II in FIG. FIG. 3 is a flowchart showing a flow of a manufacturing method according to an embodiment. FIG. 4 is a diagram for explaining the resist pattern forming process, and is a plan view of the resist pattern formed by the resist pattern forming process. 4 and 5 are diagrams for explaining the resist pattern forming step S1. FIG. 5A shows a cross section taken along the line Va-Va shown in FIG. 4, and FIG. 5B shows a cross section taken along the line Vb-Vb shown in FIG. FIG. 6 is a diagram for explaining a metal deposition process. 6A shows a cross-section corresponding to FIG. 5A, and FIG. 6B shows a cross-section corresponding to FIG. 5B. FIG. 7 is a diagram for explaining the lift-off process. 7A shows a cross section corresponding to FIG. 5A, and FIG. 7B shows a cross section corresponding to FIG. 5B. FIG. 8A and FIG. 8B are plan views showing a configuration of a modified example.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described. A method of manufacturing a thin film metal resistor according to an embodiment of the present invention includes a first thin film metal resistor including a first resistor and a second resistor having a lower resistance value per unit length than the first resistor. A method for producing a second thin film metal resistor on an insulator, the first opening for forming a first thin film metal resistor, and the second opening for forming a second thin film metal resistor A resist pattern forming process for forming a resist pattern on the insulator, a metal deposition process for depositing a metal material for a thin film metal resistor on the resist pattern, in the first opening, and in the second opening, and a resist pattern And a lift-off process for removing the metal material on the resist pattern, and in the resist pattern forming process, the width of the first opening for forming the first resistance part is formed to form the second resistance part. First Narrower than the width of the opening portion.

  In the above production method, the first and second thin film metal resistors are produced using the lift-off method. In such a method, the narrower the resist pattern opening for lift-off, the smaller the metal material that reaches the insulator, so the thin-film metal resistance becomes thinner and thinner, and the resistance value per unit length. Becomes higher. In the manufacturing method described above, this is utilized, and the width of the first opening forming the first resistance portion is made narrower than the width of the second opening forming the second resistance portion. Thereby, the resistance value per unit length of the 1st resistance part can be made higher than the resistance value per unit length of the 2nd resistance part. That is, according to the above manufacturing method, it is possible to easily manufacture a plurality of thin film metal resistors having different resistance values per unit length. And according to this manufacturing method, since such a some thin film metal resistor can be manufactured simultaneously, the increase in the number of manufacturing processes can be suppressed.

  Further, in the above method, the first thin film metal resistor further includes a contact portion provided on the upper surface with a metal film that makes contact with other wiring, and the first thin film metal resistor forms the contact portion in the resist pattern forming step. You may make the width | variety of the part of an opening wider than the width | variety of the part of the 1st opening which forms a 1st resistance part. Thereby, the contact resistance can be reduced by increasing the film thickness of the contact portion.

[Details of the embodiment of the present invention]
Hereinafter, an embodiment of a method for producing a thin film metal resistor of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  1 and 2 are diagrams showing an example of a thin film metal resistor manufactured by a manufacturing method according to an embodiment of the present invention. Fig.1 (a) is a top view which shows the structure of the 1st thin film metal resistor 10, FIG.1 (b) is a sectional side view along the II line | wire of Fig.1 (a). FIG. 2B is a plan view showing the configuration of the second thin film metal resistor 20, and FIG. 2B is a side sectional view taken along the line II-II in FIG.

A first thin-film metal resistor 10 shown in FIG. 1 has a first resistance portion 11 and two first contact portions 12. Similarly, the second thin film metal resistor 20 shown in FIG. 2 includes a second resistance portion 21 and two second contact portions 22. The first and second resistance portions 11 and 21 are portions that provide desired resistance values in the first and second thin film metal resistors 10 and 20. The first resistance portion 11 extends from one first contact portion 12 to the other first contact portion 12, and the second resistance portion 21 extends from one second contact portion 22 to the other second contact portion 22. Yes. The thickness t2 of the second resistance portion 21 is thicker than the thickness t1 of the first resistance portion 11, and the width W2 of the second resistance portion 21 is larger than the width W1 of the first resistance portion 11. Thereby, the resistance value per unit length of the second resistance part 21 is lower than the resistance value per unit length of the first resistance part 11. The constituent materials of the first and second thin film metal resistors 10 and 20 are the same as each other. For example, nickel chrome (NiCr), nickel chrome silicon (NiCrSi), chrome silicon (CrSi), tantalum nitride (TaN), chrome Examples thereof include silicide (CrSi ₂ ), chromium nitride silicide (CrSiN), and chromium silicon oxy (CrSiO).

  The first contact portion 12 is provided at both ends of the first thin film metal resistor 10. A metal film (contact metal) 31 for making contact with another wiring is provided on the upper surface of the first contact portion 12. The second contact portion 22 is provided at both ends of the second thin film metal resistor 20. A metal film (contact metal) 32 for making contact with another wiring is provided on the upper surface of the second contact portion 22. As shown in FIG. 1A, the width W <b> 3 of the first contact portion 12 is larger than the width W <b> 1 of the first resistance portion 11. Further, as shown in FIG. 1B, the thickness t <b> 3 of the first contact portion 12 is thicker than the thickness t <b> 1 of the first resistance portion 11. Thereby, the cross-sectional area of the 1st contact part 12 can be enlarged, and contact resistance can be reduced. In one embodiment, the width W3 and the thickness t3 of the first contact portion 12 are equal to the width W4 and the thickness t4 of the second contact portion 22 shown in FIG. In one embodiment, the width W4 and the thickness t4 of the second contact portion 22 are equal to the width W2 and the thickness t2 of the second resistance portion 21, respectively.

  A method for producing the first and second thin film metal resistors 10, 20 of the present embodiment will be described. FIG. 3 is a flowchart showing the flow of the manufacturing method of this embodiment. As shown in FIG. 3, the manufacturing method includes a resist pattern formation step S1, a metal deposition step S2, a lift-off step S3, and a contact metal formation step S4.

(Resist pattern formation process)
4 and 5 are diagrams for explaining the resist pattern forming step S1. FIG. 4 is a plan view of the resist pattern 41 formed in the resist pattern forming step S1. FIG. 5A shows a cross section taken along the line Va-Va shown in FIG. 4, and FIG. 5B shows a cross section taken along the line Vb-Vb shown in FIG.

  As shown in FIGS. 4 and 5, in this step, a resist pattern 41 is formed on the surface 51a of the insulating film 51 (insulator). That is, a photoresist (positive resist) is applied on the surface 51a, the photoresist is exposed to a predetermined pattern, and the exposed portion is removed with a solution (stripping solution), whereby the first opening 42 and the second opening 43 are formed. A resist pattern 41 is formed. The first opening 42 and the second opening 43 expose the insulating film 51 from the resist pattern 41. The first opening 42 is an opening for forming the first thin film metal resistor 10, and includes a first portion 42 a for forming the first resistance portion 11 and a second portion for forming the first contact portion 12. Part 42b. The second opening 43 is an opening for forming the second thin film metal resistor 20, and is a first portion 43 a for forming the second resistance portion 21 and a second portion for forming the second contact portion 22. Part 43b.

  In the present embodiment, as shown in FIG. 5A, the width W5 of the first portion 42a of the first opening 42 is made smaller than the width W6 of the first portion 43a of the second opening 43. Further, as shown in FIG. 5B, the width W7 of the second portion 42b of the first opening 42 is made wider than the width W5. In one example, the width W7 is made equal to the width W8 of the second portion 43b of the second opening 43, and the width W8 is made equal to the width W6.

  As shown in FIG. 5, the insulating film 51 may be etched through the first opening 42 and the second opening 43. In that case, the region 51b in which the first thin film metal resistor 10 is formed and the region 51c in which the second thin film metal resistor 20 is formed in the surface 51a of the insulating film 51 are slightly recessed as compared with the surrounding region. It will be.

(Metal deposition process)
FIG. 6 is a diagram for explaining the metal deposition step S2. 6A shows a cross-section corresponding to FIG. 5A, and FIG. 6B shows a cross-section corresponding to FIG. 5B. As shown in FIG. 6, in this step, the metal material 14 for thin film metal resistance is formed on the resist pattern 41, the insulating film 51 in the first opening 42, and the insulating film 51 in the second opening 43. To deposit. This deposition is performed by sputtering, for example. That is, a metal material is set as a target in a vacuum chamber, an inert gas ionized by applying a high voltage is collided, and metal material atoms on the target surface are repelled to reach each position described above. In addition, as a method for depositing the metal material 14, various methods other than sputtering can be applied.

(Lift-off process)
FIG. 7 is a diagram for explaining the lift-off process S3. 7A shows a cross section corresponding to FIG. 5A, and FIG. 7B shows a cross section corresponding to FIG. 5B. As shown in FIG. 7, in this step, the metal material 14 on the resist pattern 41 is removed (lifted off) by removing (stripping) the resist pattern 41 using a solvent (stripping solution). Thereby, on the insulating film 51, the first thin film metal resistor 10 including the first resistor portion 11 and the first contact portion 12, and the second thin film metal resistor including the second resistor portion 21 and the second contact portion 22. The body 20 remains.

(Contact metal formation process)
After the lift-off process, metal films 31 and 32 (see FIGS. 1 and 2) as contact metals are formed on the first contact portion 12 and the second contact portion 22 (contact metal formation step S4). ). Through the above steps, the first and second thin film metal resistors 10, 20 and the metal films 31, 32 shown in FIGS. 1 and 2 are suitably manufactured.

  Here, in the above-described metal deposition step S2, the smaller the opening width of the resist pattern 41, the smaller the metal material 14 that reaches the insulating film 51. Therefore, the thin-film metal resistance becomes thinner and thinner, and the unit length. The per-resistance value increases. In the present embodiment, this is utilized, and the width W5 of the first portion 42a of the first opening 42 is made narrower than the width W6 of the first portion 43a of the second opening 43, as shown in FIG. Specifically, the width W5 of the first portion 42a is determined according to the desired width W1 and the desired thickness t1 of the first resistor portion 11. Similarly, the width W6 of the first portion 43a is determined according to the desired width W2 and the desired thickness t2 of the second resistance portion 21. Thereby, the resistance value per unit length of the first resistance part 11 can be made higher than the resistance value per unit length of the second resistance part 21.

  That is, according to the manufacturing method of the present embodiment, a plurality of thin film metal resistors having different resistance values per unit length can be easily manufactured. And since such a some thin film metal resistor can be produced simultaneously, the increase in the number of manufacturing processes can be suppressed.

  In the present embodiment, in the resist pattern forming step S1, the width W7 of the second portion 42b of the first opening 42 that forms the first contact portion 12 is set to be larger than the width of the first portion 42a that forms the first resistance portion 11. It is also wide. Thereby, the film thickness t3 of the first contact portion 12 can be increased, and the width W3 can be increased to reduce the contact resistance.

(Modification)
FIG. 8A and FIG. 8B are plan views showing a configuration of a modified example of the above embodiment. The first thin-film metal resistor 10A shown in FIG. 8A has a plurality (three in FIG. 8) of first resistance portions 11 and two first contact portions 12. The plurality of first resistance portions 11 extend from one first contact portion 12 to the other first contact portion 12 and have a parallel relationship with each other. In addition, the thickness and the width | variety of each 1st resistance part 11 and the 1st contact part 12 are the same as that of 1st embodiment. The 1st thin film metal resistor of this invention may have a form like this modification. Even in such a case, the same effect as that of the above embodiment can be obtained by forming a plurality of first portions 42a of the first openings 42 of the resist pattern 41 in the manufacturing method of the above embodiment.

  Further, the first thin film metal resistor 10B shown in FIG. 8B has a first resistance portion 13 and two first contact portions 12. The 1st resistance part 13 is a part which provides a desired resistance value in the 1st thin film metal resistor 10B. The first resistance portion 13 extends from one first contact portion 12 to the other first contact portion 12. The thickness of the first resistance portion 13 is thicker than the thickness t1 of the first resistance portion 11 shown in FIG. 1, and is thinner than the thickness t2 of the second resistance portion 21 shown in FIG. Further, the width W9 of the first resistor portion 13 is larger than the width W1 of the first resistor portion 11 shown in FIG. 1 and smaller than the width W2 of the second resistor portion 21 shown in FIG. Thereby, the resistance value per unit length of the first resistance portion 13 is lower than that of the first resistance portion 11 and higher than that of the second resistance portion 21.

  In the above embodiment, by setting the width W5 of the first portion 42a of the first opening 42 of the resist pattern 41 to an arbitrary size, for example, as in the first thin film metal resistor 10B of the present modification, the first The resistance value per unit length of the resistance portion can be variously changed. Accordingly, it is possible to easily produce three or more thin film metal resistors having different resistance values per unit length while suppressing an increase in the number of manufacturing steps.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment and the modification, the configuration in which the contact portions are provided at both ends of the resistance portion is illustrated, but the thin film metal resistor manufactured according to the present invention can be formed at various locations in the integrated circuit.

DESCRIPTION OF SYMBOLS 10, 10A, 10B ... 1st thin film metal resistor, 11 ... 1st resistance part, 12 ... 1st contact part, 13 ... 1st resistance part, 14 ... Metal material, 20 ... 2nd thin film metal resistor, 21 ... 2nd resistance part, 22 ... 2nd contact part, 31, 32 ... Metal film, 41 ... Resist pattern, 42 ... 1st opening, 43 ... 2nd opening, 51 ... Insulating film, S1 ... Resist pattern formation process, S2 ... Metal deposition step, S3 ... lift-off step, S4 ... contact metal formation step.

Claims (2)

A first thin film metal resistor including a first resistor and a second thin film metal resistor including a second resistor having a lower resistance value per unit length than the first resistor are formed on an insulator. A method,
Forming a resist pattern having a first opening for forming the first thin film metal resistor and a second opening for forming the second thin film metal resistor on the insulator; ,
A metal deposition step of depositing a metal material for a thin film metal resistor on the resist pattern, in the first opening, and in the second opening;
A lift-off step of removing the metal material on the resist pattern by removing the resist pattern;
With
In the resist pattern forming step, the width of the first opening that forms the first resistance portion is narrower than the width of the second opening that forms the second resistance portion. Manufacturing method. The first thin film metal resistor further has a contact portion provided on the upper surface with a metal film that makes contact with other wiring,
The width of the part of said 1st opening which forms said contact part in the said resist pattern formation process is made wider than the width | variety of said 1st opening part which forms said 1st resistance part. Thin film metal resistance fabrication method.

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