CN106252253A - A kind of method testing the round and smooth degree in active area top - Google Patents

Abstract

The invention provides a kind of method testing the round and smooth degree in active area top, including: measure the active area top residual top live width of hard mask layers, the residual thickness of hard mask layers and the angle of inclination of hard mask layers after shallow groove isolation etching completes, and calculate live width bottom hard mask layers；Measure live width, shallow groove depths and the angle of inclination of active area bottom the active area after shallow groove isolation etching completes, and calculate active area top development length；Utilize optics live width measuring instrument to measure and calculate active area top development length and characterize the round and smooth degree in active area top；Follow-up shallow trench etch process parameters is quantitatively regulated according to active area top development length.

Description

A kind of method testing the round and smooth degree in active area top

Technical field

The present invention relates to field of semiconductor manufacture, it is more particularly related to a kind of test active area top is round and smooth The method of degree.

Background technology

Along with developing rapidly of super large-scale integration (VLSI) and ULSI (ULSI), MOS device Size be steadily decreasing.While device size scaled down, running voltage but the most correspondingly geometric ratio reduction, thus Electric field intensity in working area is increased；On the other hand, in etching because of shallow trench, existing defects, top pattern be the roundest and the most smooth or side Wall connects reasons such as having some setbacks, occurs that internal field concentrates, and easily produces internal discharge and forms many conductive channels.Particularly In the case of shallow trench top is the roundest and the most smooth, ISSG (the steam generation in situ) oxidated layer thickness being grown on tip can be thinning, office Portion's pressure abruptly increase, in working area, electronics is easier to migrate, thus forms leakage current.

The edge (the namely top of active area) of fleet plough groove isolation structure leaks electricity mainly due to sharp-pointed groove drift angle It is that gate electric field becomes to concentrate, causes edge's threshold voltage to reduce, and produce a Low threshold path.Particularly wedge angle region Territory, charge distribution density increases, and the electric field intensity of generation is maximum, and less grid voltage will cause transoid.And it is rounder and more smooth Active area drift angle can allow electronics distributed areas uniform, and electric field intensity is also uniformly distributed, thus effectively reduces electric leakage, makes device more Tend to idealization, the most only could open reaching threshold voltage when.Degree round and smooth for active area top (radius of curvature) With the situation of point discharge, groove top radius of curvature is the biggest, and local pressure is the least, leaks electricity the least.

A very in-depth study has been had for above-mentioned electric leakage reason, but how real-time testing during scale of mass production The round and smooth degree in active area top goes back the method that neither one is the most feasible, has electrode temperature the etch rate from etching cavity and cavity The aspects such as degree carry out analogue active district apical curvature radius, but this all cannot accomplish real-time online detection function.

Summary of the invention

The technical problem to be solved is for there is drawbacks described above in prior art, it is provided that one utilizes optics Wire width measuring instrument (Optical Critical Dimension is called for short OCD) on-line testing active area top droop length carrys out table The method levying apical curvature radius, the method can detect active area apical curvature radius data the most in real time, find in time Problem, thus avoid because the drift of etching cavity environment causes active area apical curvature radius to occur drift to detect Arrive, this electrology characteristic having a strong impact on device circuitry and reliability.

In order to realize above-mentioned technical purpose, according to the present invention, it is provided that a kind of method testing the round and smooth degree in active area top, Including:

First step: measure the top live width of the active area top residual hard mask layers after shallow groove isolation etching completes Top_CD, residual thickness THK of hard mask layers_SiNAnd the tilt angle alpha of hard mask layers, and calculate at the bottom of hard mask layers Portion's live width Mid_CDSize；

Second step: measure live width Bot bottom the active area after shallow groove isolation etching completes_CD, shallow groove depths His with And the inclination angle beta of active area, and calculate active area top development length a:

$a=\frac{({\mathrm{Bot}}_{CD}-{\mathrm{Mid}}_{CD})}{2}-\frac{H_{Si}}{\tan \mathrm{\β}};$

Third step: utilize optics live width measuring instrument to measure and calculate active area top development length and characterize active area top The round and smooth degree in portion；

4th step: quantitatively regulate follow-up shallow trench etch process parameters according to active area top development length.

Preferably, after continuing shallow trench etch process parameters after adjustment, incoming for wafer etching cavity is carried out shallow trench quarter Etching technique.

Preferably, live width Mid bottom hard mask layers_CDComputing formula be:

${\mathrm{Mid}}_{CD}=\frac{{\mathrm{THK}}_{SiN}}{\tan \mathrm{\α}}\×2+{\mathrm{Top}}_{CD}.$

Preferably, the computing formula of active area top development length a is:

$a=\frac{({\mathrm{Bot}}_{CD}-{\mathrm{Mid}}_{CD})}{2}-\frac{H_{Si}}{\tan \mathrm{\β}}.$

Preferably, in the 4th step using active area top development length as active area top round and smooth degree characterization parameter.

Preferably, the method for the round and smooth degree in described test active area top is used for manufacturing super large-scale integration.

Preferably, the method for the round and smooth degree in described test active area top is used for manufacturing ULSI.

Preferably, first step uses optics live width measuring instrument to measure the active area top after shallow groove isolation etching completes Top live width Top of residual hard mask layers_CD, residual thickness THK of hard mask layers_SiNAnd the inclination angle of hard mask layers Degree α, and calculate live width Mid bottom hard mask layers_CDSize.

Preferably, second step uses optics live width measuring instrument to measure bottom the active area after shallow groove isolation etching completes Live width Bot_CD, shallow groove depths His and the inclination angle beta of active area.

The present invention measures the structural parameters after shallow trench etches by optics live width measuring instrument and (includes but not limited to active area The top residual top live width of hard mask layers, the residual thickness of hard mask layers and the angle of inclination of hard mask layers), and Calculate hard mask layers bottom line roomy little；By optics live width measuring instrument measure live width bottom active area, shallow groove depths, And the angle of inclination of active area, and calculate active area top round and smooth degree straight length；Optics live width measuring instrument is tested Active area top round and smooth degree straight length is as on-line checking data, the round and smooth degree in detection active area top, thus accomplishes the most anti- The round and smooth degrees of data in feedback active area top, prevents from, because etching cavity drift causes shallow ditch groove structure top round and smooth degree instability, causing Device creepage increases and occurs that product is abnormal.

Accompanying drawing explanation

In conjunction with accompanying drawing, and by with reference to detailed description below, it will more easily the present invention is had more complete understanding And its adjoint advantage and feature is more easily understood, wherein:

Fig. 1 schematically shows the stream of the method for the round and smooth degree in test active area top according to the preferred embodiment of the invention Cheng Tu.

It should be noted that accompanying drawing is used for illustrating the present invention, and the unrestricted present invention.Note, represent that the accompanying drawing of structure can Can be not necessarily drawn to scale.Further, in accompanying drawing, same or like element indicates same or like label.

Detailed description of the invention

In order to make present disclosure more clear and understandable, below in conjunction with specific embodiments and the drawings in the present invention Appearance is described in detail.

Fig. 1 schematically shows the stream of the method for the round and smooth degree in test active area top according to the preferred embodiment of the invention Cheng Tu.

As it is shown in figure 1, the method for the round and smooth degree in test active area top includes according to the preferred embodiment of the invention:

First step S1: use optics live width measuring instrument to measure the active area top residual after shallow groove isolation etching completes Top live width Top of hard mask layers_CD, residual thickness THK of hard mask layers_SiNAnd the tilt angle alpha of hard mask layers, And calculate live width Mid bottom hard mask layers_CDSize:

${\mathrm{Mid}}_{CD}=\frac{{\mathrm{THK}}_{SiN}}{\tan \mathrm{\α}}\×2+{\mathrm{Top}}_{CD};$

Second step S2: use optics live width measuring instrument to measure live width bottom the active area after shallow groove isolation etching completes Bot_CD, shallow groove depths His and the inclination angle beta of active area, and calculate active area top development length a:

$a=\frac{({\mathrm{Bot}}_{CD}-{\mathrm{Mid}}_{CD})}{2}-\frac{H_{Si}}{\tan \mathrm{\β}};$

Third step S3: utilize optics live width measuring instrument to measure and calculate active area top development length and characterize active area The round and smooth degree in top；

4th step S4: quantitatively regulate according to active area top development length a (active area top round and smooth degree characterization parameter) Follow-up shallow trench etch process parameters, reaches the purpose maintaining the round and smooth degree in active area top steady.

Hereafter, after continuing shallow trench etch process parameters after adjustment, incoming for wafer etching cavity is carried out shallow trench etching Technique.

The method of the round and smooth degree in test active area top is effectively used for manufacturing super large according to the preferred embodiment of the invention Scale integrated circuit and ULSI.

Thus, in the present invention, the structural parameters after shallow trench etches are measured by optics live width measuring instrument, through relevant Parameter calculates active area structure top round and smooth degree characterization parameter, and as on-line checking data, can monitor etching technics in real time With the stability of etching cavity environment, number can also be characterized according to the round and smooth degree in active area top simultaneously and quantitatively regulate shallow trench etching Technological parameter regulates and controls the round and smooth degree in active area top, prevents because etching cavity drift causes shallow ditch groove structure top round and smooth degree shakiness Fixed, cause device creepage to increase and occur that product is abnormal.

Furthermore, it is necessary to explanation, unless stated otherwise or point out, otherwise the term in description " first ", " the Two ", " the 3rd " etc. describe be used only for distinguishing in description each assembly, element, step etc. rather than for representing each Logical relation between assembly, element, step or ordering relation etc..

Although it is understood that the present invention discloses as above with preferred embodiment, but above-described embodiment being not used to Limit the present invention.For any those of ordinary skill in the art, without departing under technical solution of the present invention ambit, Technical solution of the present invention is made many possible variations and modification by the technology contents that all may utilize the disclosure above, or is revised as Equivalent embodiments with change.Therefore, every content without departing from technical solution of the present invention, according to the technical spirit pair of the present invention Any simple modification made for any of the above embodiments, equivalent variations and modification, all still fall within the scope of technical solution of the present invention protection In.

Claims (9)

1. the method testing the round and smooth degree in active area top, it is characterised in that including:

First step: measure the top live width of the active area top residual hard mask layers after shallow groove isolation etching completes Top_CD, residual thickness THK of hard mask layers_SiNAnd the tilt angle alpha of hard mask layers, and calculate at the bottom of hard mask layers Portion's live width Mid_CDSize；

Second step: measure live width Bot bottom the active area after shallow groove isolation etching completes_CD, shallow groove depths His and having The inclination angle beta of source region, and calculate active area top development length a:

$a=\frac{({\mathrm{Bot}}_{CD}-{\mathrm{Mid}}_{CD})}{2}-\frac{H_{Si}}{tan\mathrm{\β}};$

Third step: utilize optics live width measuring instrument to measure and calculate active area top development length value and characterize active area top Round and smooth degree；

4th step: quantitatively regulate follow-up shallow trench etch process parameters according to active area top development length.

The method of the round and smooth degree in test active area top the most according to claim 1, it is characterised in that also include: after adjustment After continuous shallow trench etch process parameters, incoming for wafer etching cavity is carried out shallow trench etching technics.

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that hard mask layers Bottom live width Mid_CDComputing formula be:

${\mathrm{Mid}}_{CD}=\frac{{\mathrm{THK}}_{SiN}}{\tan \mathrm{\α}}\×2+{\mathrm{Top}}_{CD}.$

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that active area top The computing formula of development length a is:

$a=\frac{({\mathrm{Bot}}_{CD}-{\mathrm{Mid}}_{CD})}{2}-\frac{H_{Si}}{tan\mathrm{\β}}.$

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that in the 4th step Using active area top development length as active area top round and smooth degree characterization parameter.

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that described test has The method of the round and smooth degree in source region top is used for manufacturing super large-scale integration.

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that described test has The method of the round and smooth degree in source region top is used for manufacturing ULSI.

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that first step makes The top live width of the active area top residual hard mask layers after shallow groove isolation etching completes is measured with optics wire width measuring instrument Top_CD, residual thickness THK of hard mask layers_SiNAnd the tilt angle alpha of hard mask layers, and calculate at the bottom of hard mask layers Portion's live width Mid_CDSize.

The method of the round and smooth degree in test active area top the most according to claim 1 and 2, it is characterised in that second step makes Live width Bot bottom the active area after shallow groove isolation etching completes is measured with optics wire width measuring instrument_CD, shallow groove depths His with And the inclination angle beta of active area.