CN103325678A - IC two- micrometer-thick aluminum etching process method - Google Patents

Abstract

The invention relates to an IC two-micrometer-thick aluminum etching process method and belongs to the technical field of etching a thick aluminum layer manufactured in the technique of a semiconductor integrated circuit device. Firstly, the thick aluminum layer of most of the thickness is etched by a high-orientation plasma etching machine utilizing a dry method in the etching technology, subsequent spraying type wet etching is used for finishing embellishing a resolution ratio of etched lines, thoroughness and rim regularity of the thick aluminum layer. The IC two- micrometer aluminum etching process method is advanced, reasonable, capable of reaching the requirements for the dimension of etched lines, the resolution ratio, the regularity of side walls of the thick aluminum layer and totally free of residues.

Description

IC2 micron thick aluminum etching process

Technical field

The present invention relates to manufacturing technology, especially IC 2.0 micron thick aluminium etching technics that integrated circuit (IC) is made, belong to the technical field of the thick aluminium lamination etching of semiconductor device technique manufacturing.

Background technology

Along with the fast development of integrated circuit (IC) manufacturing and application technology, the user has the thickness that proposes the chip aluminum metal layer to propose thicker requirement more.The aluminum layer thickness that manufactures and designs of the original standard of IC is 1.5 microns, is 2.0 microns and require now the aluminum layer thickness of etching.The topological graph of the aluminium lamination that aluminum layer thickness will be designed under 1.5 microns standards, after lines thickness is increased to 2.0 microns and etching, the line thickness of figure, the spacing between figure and but be not a nothing the matter to the requirement that the quality that they require need still satisfy former standard.

Photoetching is a kind of with the integrated technology of figure duplicating with the etching phase combination.Use first the method for photographic copying, the figure of photo etched mask is accurately duplicated be coated in medium (the medium thin layers such as polysilicon, silicon nitride, silicon dioxide, aluminium) above the lip-deep photoresist (photoresist).Then, under the protection of photoresist (being photoresist) required etching material is carried out selective etch, the part that photoresist is protected stays, and the part of not protected is removed, thereby obtains required figure at material to be etched.

Summary of the invention

The objective of the invention is to be the satisfying the market needs, the aluminum layer thickness that a kind of etching is provided is 2 microns etching process, and so that the etching of thick aluminium lamination neatly the reaching requirement and do not have residue fully of line size, definition and side wall as a result satisfied the requirement of former standard.

The objective of the invention is to be achieved through the following technical solutions, IC 2 micron thick aluminum etching process, to adopt first the usefulness dry plasma etching machine of high directionality and most of thickness of the thick aluminium lamination of lithographic technique etching, adopt again follow-up atomizing wet etching to modify with the regularity of finishing lines resolution to thick aluminium lamination etching, completeness, edge, may further comprise the steps:

1) at the aluminium lamination surface-coated positive photoetching rubber of silicon substrate film, bondline thickness is the 2.45-2.50 micron;

2) positive photoetching rubber that applies is pressed the technological operation of conventional aluminum photolithographic exposure until develop, obtain required photoetching

The glue pattern carried out 140 ℃ of bakings after 20 minutes after the development, at room temperature cooled off 30 minutes;

3) to step 2) photoetching agent pattern that obtains carries out dry method aluminium etching: equipment adopts the ATM-8300 plasma etching machine; Material electronics is pure: Cl ₂(chlorine), BCl ₃(boron chloride), CHF ₃(silicofluoroform), N ₂(nitrogen); Its step is as follows:

A) etching machine is evacuated down to 20 milli torrs;

B) pass into the BCl of 30 liter/mins of clocks of flow ₃The CHF of (boron chloride) and 20 liter/mins of clocks ₃(three

Silicon fluoride);

C) transfer back bias voltage :-120V, maximum radio frequency power: 1500W, continue etching 1:00 minute;

D) Cl of 60 liter/mins of clocks of adding ₂, 80 liter/mins of clocks BCl ₃The CHF of (boron chloride) and 10 liter/mins of clocks ₃(silicofluoroform), maximum radio frequency power 1600W, back bias voltage: under-235V the condition etching 10:00 minute;

E) at flow be the Cl of 40 liter/mins of clocks ₂The BCl of (chlorine), 60 liter/mins of clocks ₃(boron chloride), under maximum radio frequency power 1500W, the back bias voltage-200V condition, etching 3 minutes and 30 seconds, logical nitrogen is closed Cl simultaneously ₂(chlorine), BCl ₃(boron chloride), CHF ₃(silicofluoroform)

Air valve, and close the switch of radio-frequency power and back bias voltage; Keep logical nitrogen to come out of the stove after 10 minutes;

F) rush immediately pure water after coming out of the stove, washed by water at least 15 minutes;

G) bath after post bake: 180 ℃, the baking 20 minutes, under the room temperature cooling 20 minutes;

H) play glue after the cooling: equipment: DES-206, use radio-frequency power 200W, bombardment is 5 minutes under air pressure 1.0 torr conditions, destroys the counterdie of the window that is etched;

4) use spraying wet etching aluminium after the dry method aluminium etching: equipment: SPW-612-A, corrosive liquid: the aluminium corrosive liquid, fluid temperature: 50 ± 1 ℃, etching fog pressure: 0.4 ~ 0.5kg/cm ², eject position: silicon chip center, spray configuration: fan-shaped; Spray angle: 45 ⁰, washing rotation etching platform: 120-S, washing time: No. 1 groove: 5 minutes, No. 2 grooves: 5 minutes, No. 3 grooves 5 minutes;

5) check after the washing: reach the dry method work step that removes photoresist under will the qualified product without residual aluminium, latticing, erosion;

6) dry method is removed photoresist: equipment: OPM-2100 dry method resist remover, radio-frequency power: 500W, 45 minutes.

Process of the present invention is rationally advanced, adopt positive photoresist to be coated on 2.0 microns aluminium laminations, the positive photoresist coating thickness is between 2.45 to 2.50 microns, and sought to the aluminium lamination anisotropic etching method of---only in the direction etching perpendicular to substrate---, avoiding the horizontal erosion of aluminium lamination, thereby obtain very vertical side wall.So, adopt ripe dry plasma anisotropic etching method here, and use first the thickness of the most of aluminium lamination of this method etching.In the exposure of common aluminium lamination photoetching process, the dry plasma etching after the post bake work step, the dry plasma etching process is mainly 4 processes: the first step, with boron chloride and the isoionic pre-etching of fluoroform; Second step is with chlorine, boron chloride and the isoionic main etching of fluoroform; The 3rd step, the addendum etching of employing chlorine and boron chloride; The 4th step, nitrogen protection cooling terminal procedure.Be to eliminate dry etching legacy many (Fig. 2), and be difficult for the defective of check, increase and replenished wet etching so that the oddment that dry etching is left over eliminates, and can be beneficial to inspection and technique is reprocessed.Wet etching uses the method etching aluminium of spraying wet etching, finally obtains the satisfactory result of 2.0 micron thickness aluminium lamination etchings, line size, definition and side wall neatly reach requirement, and do not have residue fully, satisfy the requirement of standard.

Description of drawings

Fig. 1 uses 1.5 microns aluminium lamination etching technics of existing standard only to increase the as a result figure of 2.0 microns aluminium laminations of etch period etch thicknesses, visible lines obviously reduce and the edge very irregular.

Fig. 2 is the result of the aluminium lamination etching after the existing dry etching work step, and the lines after visible aluminium lamination is etched are better, but the zone has obvious residue (stain).

Fig. 3 is the order of reasonable disposition dry and wet way etching of the present invention, and before being dry-etched in, wet etching is rear, and suitably controls the etching figure as a result of 2.0 micron thickness aluminium laminations of the satisfactory quality that etching condition obtains.

Embodiment

This IC is as follows with the lithographic method of 2 micron thick aluminium lamination etching technics:

1. between 2.45 to 2.48 microns, every batch is detected 5 with 5 points (upper, middle and lower, left and right) testing result for aluminium lamination surface-coated positive photoetching rubber, bondline thickness, and every mean value is between 2.45 to 2.50 microns;

2. press the technological operation of primary aluminum photolithographic exposure until after developing;

3. post bake work step condition: 140 ℃, baking 20 minutes, cooled off 30 minutes;

4. dry method aluminium etching: equipment: 2300 plasma etching machines; Material: electronic pure: Cl ₂(chlorine), BCl ₃(boron chloride), CHF ₃(silicofluoroform), N ₂(nitrogen); Step:

1. be evacuated down to 20 milli torrs;

2. pass into the BCl of 30 liter/mins of clocks ₃The CHF of (boron chloride) and 20 liter/mins of clocks ₃(silicofluoroform);

3. transfer back bias voltage :-120V, maximum radio frequency power: 1500W, continue corrosion 1:00 minute;

4. the Cl that adds inbound traffics (liter/min clock) 60 ₂, 80 BCl ₃(boron chloride) and 10 CHF ₃(silicofluoroform), maximum radio frequency power 1600W, back bias voltage: corrosion is 10:00 minute under the-235V condition;

5. be 40 Cl at flow (liter/min clock) ₂(chlorine), 60 BCl ₃(boron chloride) under maximum radio frequency power 1500W, the back bias voltage-200V condition, corroded 3 minutes and 30 seconds,

6. logical nitrogen is closed Cl simultaneously ₂(chlorine), BCl ₃(boron chloride), CHF ₃The air valve of (silicofluoroform), and close the switch of radio-frequency power and back bias voltage; Kept logical nitrogen 10 minutes;

7. rush immediately pure water after coming out of the stove, washed by water at least 15 minutes;

8. post bake: 180 ℃, baking 20 minutes, cooled off 20 minutes;

9. play glue: equipment: DES-206, use radio-frequency power 200W, bombardment is 5 minutes under air pressure 1.0 torr conditions, destroys the cull of the window that is etched;

5. with spraying wet etching aluminium: equipment: SPW-612-A, etching liquid: the aluminium corrosive liquid, fluid temperature: 50 ± 1 ℃, etching fog pressure: 0.4 ~ 0.5kg/cm ², eject position: silicon chip center, spray configuration: fan-shaped; Spray angle: 45 ⁰, washing rotation etching platform: 120-S, washing time: No. 1 groove: 5 minutes, No. 2 grooves: 5 minutes, No. 3 grooves 5 minutes;

10. check: without residual aluminium, latticing, erosion; Reach the dry method work step that removes photoresist under qualified;

Dry method is removed photoresist: equipment: OPM-2100 dry method resist remover, radio-frequency power: 500W, time: 45 minutes;

So far, IC2.0 micron thickness aluminium lamination success etching technics is finished.Etching figure satisfactory result is seen Fig. 3.

The IC2.0 micron thickness aluminium lamination etching technics of the present invention test is finished checking batch and effect:

The lot number sheet is counted average qualification rate

GIFI036A-240634 48P 95.80%

GIFI036A-240635 48P 97.11%

GIFI036A-250314 48P 95.59%

GIFI036A-250320 47P 97.43%

GIFI036A-240633 48P 95.97%

GIFI036A-250316 47P 96.71%

GIFI036A-250317 48P 94.90%

GIFI036A-250318 48P 96.07%

GIFI036A-240636 47P 95.98%

GIFI036A-250315 48P 96.50%

Process of the present invention is used through test, and the output goods have more than 500, and the product surface of making is not unusual, and average qualification rate is greater than 94.90%.

Claims (1)

1.IC2 micron thick aluminum etching process, it is characterized in that: adopt first the usefulness dry plasma etching machine of high directionality and most of thickness of the thick aluminium lamination of lithographic technique etching, adopt again follow-up atomizing wet etching to modify with the regularity of finishing lines resolution to thick aluminium lamination etching, completeness, edge, may further comprise the steps:

1) at the aluminium lamination surface-coated positive photoresist of silicon substrate film, bondline thickness is the 2.45-2.50 micron;

2) positive photoresist that applies is pressed the technological operation of conventional aluminum photolithographic exposure until develop, obtain required photoetching agent pattern, carry out 140 ℃ of bakings after the development after 20 minutes, at room temperature cooled off 30 minutes;

3) to step 2) photoetching agent pattern that obtains carries out dry method aluminium etching: equipment adopts the ATM-8300 plasma etching machine; Material electronics is pure: Cl ₂, BCl ₃, CHF ₃, N ₂Its step is as follows:

A) etching machine is evacuated down to 20 milli torrs;

B) pass into the BCl of 30 liter/mins of clocks of flow ₃CHF with 20 liter/mins of clocks ₃

C) transfer back bias voltage :-120V, maximum radio frequency power: 1500W, continue etching 1:00 minute;

D) Cl of 60 liter/mins of clocks of adding ₂, 80 liter/mins of clocks BCl ₃CHF with 10 liter/mins of clocks ₃, maximum radio frequency power 1600W, back bias voltage: under-235V the condition etching 10:00 minute;

E) at flow be the Cl of 40 liter/mins of clocks ₂, 60 liter/mins of clocks BCl ₃, under maximum radio frequency power 1500W, the back bias voltage-200V condition, etching 3 minutes and 30 seconds, logical nitrogen is closed Cl simultaneously ₂, BCl ₃, CHF ₃Air valve, and close the switch of radio-frequency power and back bias voltage; Keep logical nitrogen to come out of the stove after 10 minutes;

F) rush immediately pure water after coming out of the stove, washed by water at least 15 minutes;

G) bath after post bake: 180 ℃, the baking 20 minutes, under the room temperature cooling 30 minutes;

H) play glue after the cooling: equipment: DES-206, use radio-frequency power 200W, bombardment is 5 minutes under air pressure 1.0 torr conditions, destroys the counterdie of the window that is etched;

4) use spraying wet etching aluminium after the dry method aluminium etching: equipment: SPW-612-A, corrosive liquid: the aluminium corrosive liquid, fluid temperature: 50 ± 1 ℃, etching fog pressure: 0.4 ~ 0.5kg/cm ², eject position: silicon chip center, spray configuration: fan-shaped; Spray angle: 45 ⁰, washing rotation etching platform: 120-S, washing time: No. 1 groove: 5 minutes, No. 2 grooves: 5 minutes, No. 3 grooves 5 minutes;

5) check after the washing: reach the dry method work step that removes photoresist under will the qualified product without residual aluminium, latticing, erosion;

6) dry method is removed photoresist: equipment: OPM-2100 dry method resist remover, radio-frequency power: 500W, 45 minutes.

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