Summary of the invention
The present invention is intended to solve at least one of technical problem that exists in the prior art.
Further investigate the back through the inventor and find that the measuring principle of terminal point measurement mechanism and on-line measurement device all is the same.For example, for the silica polishing, the measuring principle of terminal point measurement mechanism and on-line measurement device is the light reflection.For the copper polishing, the measuring principle of terminal point measurement mechanism and on-line measurement device is a current vortex.
For this reason, one object of the present invention is to propose a kind of cmp method that can reduce equipment cost and production cost widely.
To achieve these goals, propose a kind of cmp method according to embodiments of the invention, said cmp method comprises: A) utilize the terminal point measurement mechanism to measure the preceding value of thickness of a plurality of points on the wafer; B) according to value before the thickness of said a plurality of points said wafer is carried out chemically mechanical polishing; And C) is worth after utilizing said terminal point measurement mechanism to measure the thickness of said a plurality of points; And judge according to value behind the thickness of said a plurality of points whether the surface finish thickness of said wafer is even; If the surface finish of said wafer is in uneven thickness, it is even until the surface finish thickness of said wafer then according to the difference that is worth behind value and the thickness before the thickness of said a plurality of points said wafer to be carried out chemically mechanical polishing.
Be worth after the value and thickness through utilizing said terminal point measurement mechanism to detect before the thickness of said wafer according to the cmp method of the embodiment of the invention, and utilize said terminal point measurement mechanism detects said wafer in real time in CMP process the variation of thickness so that judge the terminal point of chemically mechanical polishing.Need not to re-use the on-line measurement device when utilizing cmp method according to the embodiment of the invention that wafer is carried out chemically mechanical polishing like this; Thereby not only can simplify the structure of the chemical-mechanical polisher that carries out chemically mechanical polishing, the cost of reduction chemical-mechanical polisher widely, and can reduce the chemically mechanical polishing cost of wafer widely.
In addition, the cmp method according to the embodiment of the invention can have following additional technical characterictic:
According to one embodiment of present invention, said steps A) comprising: A-1) utilize the said wafer of rubbing head clamping and said wafer is contacted with polishing pad, the center of wherein said wafer is corresponding with said terminal point measurement mechanism; And A-2) said rubbing head rotation and move back and forth so that said terminal point measurement mechanism is worth before measuring the thickness of the said a plurality of points on the said wafer with respect to said polishing pad, wherein said polishing pad is static.
According to one embodiment of present invention, said step C) comprising: C-1) utilize the said wafer of said rubbing head clamping and said wafer is contacted with said polishing pad, the center of wherein said wafer is corresponding with said terminal point measurement mechanism; C-2) said rubbing head rotation and move back and forth so that said terminal point measurement mechanism is worth after measuring the thickness of the said a plurality of points on the said wafer with respect to said polishing pad, wherein said polishing pad is static; C-3) maximum in the value and the difference of minimum of a value behind the thickness of the said a plurality of points of calculating; If the difference of said maximum and said minimum of a value is not more than predetermined value; Then the surface finish thickness of said wafer is even, otherwise the surface finish of said wafer is in uneven thickness; And C-4) if the surface finish of said wafer is in uneven thickness; Calculate the difference that is worth after the value and thickness before the thickness of said a plurality of points respectively so that obtain the thickness removal value of said a plurality of points, according to the thickness removal value of said a plurality of points said wafer is carried out chemically mechanical polishing and be not more than said predetermined value until the difference of said maximum and said minimum of a value.
According to one embodiment of present invention, said predetermined value is 100 nanometers.
According to one embodiment of present invention, said reciprocating motion is reciprocal translation, like this can be so that operation.
According to one embodiment of present invention, said rubbing head can be convenient to operation so more along the radially back and forth translation of said polishing pad.
According to one embodiment of present invention, the stroke of said reciprocal translation is 50mm-300mm.Can make said a plurality of point be distributed in the whole burnishing surface of said wafer like this, thereby can know the thickness situation of zones of different on the surface of said wafer more all sidedly.
According to one embodiment of present invention, said reciprocating frequency is 5 times/minute-40 times/minute.Can measure exactly like this before the thickness of said a plurality of points and be worth after the value and thickness.
According to one embodiment of present invention, said reciprocating frequency is 10 times/minute-30 times/minute.Can measure more exactly like this before the thickness of said a plurality of points and be worth after the value and thickness.
According to one embodiment of present invention, the rotating speed of said rubbing head is 60rpm-120rpm.Can measure more exactly like this before the thickness of said a plurality of points and be worth after the value and thickness.
Additional aspect of the present invention and advantage part in the following description provide, and part will become obviously from the following description, or recognize through practice of the present invention.
The specific embodiment
Describe embodiments of the invention below in detail, the example of said embodiment is shown in the drawings, and wherein identical from start to finish or similar label is represented identical or similar elements or the element with identical or similar functions.Be exemplary through the embodiment that is described with reference to the drawings below, only be used to explain the present invention, and can not be interpreted as limitation of the present invention.
In description of the invention; It will be appreciated that; Term " vertically ", " laterally ", " on ", the orientation of indications such as D score, " preceding ", " back ", " left side ", " right side ", " vertically ", " level ", " top ", " end " " interior ", " outward " or position relation be for based on orientation shown in the drawings or position relation; Only be to describe with simplifying for the ease of describing the present invention; Rather than the device or the element of indication or hint indication must have specific orientation, with specific azimuth configuration and operation, therefore can not be interpreted as limitation of the present invention.
In addition, term " first ", " second " only are used to describe purpose, and can not be interpreted as indication or hint relative importance.
In description of the invention, unless otherwise prescribed and limit, need to prove; Term " installation ", " linking to each other ", " connection " should be done broad understanding, for example, can be mechanical connection or electrical connection; Also can be the connection of two element internals, can be directly to link to each other, and also can link to each other indirectly through intermediary; For those of ordinary skill in the art, can understand the concrete implication of above-mentioned term as the case may be.
Further investigate the back through the inventor and find, because polishing fluid is introduced from the outside, therefore fresh polishing fluid can't in time arrive crystal column surface, makes the local polishing thickness of wafer less than predetermined standard value, thereby causes the crystal column surface polishing thickness inhomogeneous.
With reference to Fig. 1 the cmp method according to the embodiment of the invention is described below.As shown in Figure 1, comprise according to the cmp method of the embodiment of the invention:
A) utilize the terminal point measurement mechanism to measure the preceding value of thickness of a plurality of points on the wafer;
B) according to value before the thickness of said a plurality of points said wafer is carried out chemically mechanical polishing; With
C) be worth after utilizing said terminal point measurement mechanism to measure the thickness of said a plurality of points; And judge according to value behind the thickness of said a plurality of points whether the surface finish thickness of said wafer is even; If the surface finish of said wafer is in uneven thickness, it is even until the surface finish thickness of said wafer then according to the difference that is worth behind value and the thickness before the thickness of said a plurality of points said wafer to be carried out chemically mechanical polishing.
Be worth after the value and thickness through utilizing said terminal point measurement mechanism to detect before the thickness of said wafer according to the cmp method of the embodiment of the invention, and utilize said terminal point measurement mechanism detects said wafer in real time in CMP process the variation of thickness so that judge the terminal point of chemically mechanical polishing.Need not to re-use the on-line measurement device when utilizing cmp method according to the embodiment of the invention that wafer is carried out chemically mechanical polishing like this; Thereby not only can simplify the structure of the chemical-mechanical polisher that carries out chemically mechanical polishing, the cost of reduction chemical-mechanical polisher widely, and can reduce the chemically mechanical polishing cost of wafer widely.
Like Fig. 2 and shown in Figure 4, in some embodiments of the invention, said steps A) can comprise:
A-1) can utilize the said wafer of rubbing head 100 clampings also said wafer is contacted with polishing pad 200, the center of wherein said wafer can be corresponding with said terminal point measurement mechanism so that confirm to measure initial point; With
A-2) rubbing head 100 can rotation and rubbing head 100 can move back and forth so that said terminal point measurement mechanism is worth before can measuring the thickness of the said a plurality of points on the said wafer with respect to polishing pad 200, wherein polishing pad 200 can be static.
When before utilizing said terminal point measurement mechanism to measure the thickness of the said a plurality of points on the said wafer, being worth, the surface of said wafer can contact with polishing pad 200.The surface of wherein said wafer is meant the burnishing surface of said wafer.Can know the thickness situation of zones of different on the surface of said wafer according to value before the thickness of said a plurality of points; Thereby can confirm CMP process (for example polishing fluid composition, polishing fluid temperature, polish pressure etc.) according to the thickness situation of the zones of different on the surface of said wafer, so that improve the uniformity of the surface finish thickness of said wafer.How confirm that according to the thickness situation of the zones of different on the surface of said wafer CMP process is that those skilled in the art know, therefore no longer describe in detail.
In an example of the present invention, when before utilizing said terminal point measurement mechanism to measure the thickness of the said a plurality of points on the said wafer, being worth, the rubbing head 100 of the said wafer of clamping can be with respect to polishing pad 200 reciprocal translations, like this can be so that operation.Particularly, the rubbing head 100 of the said wafer of clamping can along polishing pad 200 radially with respect to polishing pad 200 reciprocal translations, can be convenient to more like this operation.Wherein, the stroke of said reciprocal translation can be 50mm-300mm, can make said a plurality of point be distributed in the whole burnishing surface of said wafer like this, thereby can know the thickness situation of zones of different on the surface of said wafer more all sidedly.Said reciprocating frequency can be 5 times/minute-40 times/minute, can measure the preceding value of thickness of said a plurality of points so exactly.Advantageously, the stroke of said reciprocal translation can be 100mm-150mm, and said reciprocating frequency can be 10 times/minute-30 times/minute, can measure the preceding value of thickness of said a plurality of points so more exactly.In a concrete example of the present invention, the rotating speed of rubbing head 100 can be 60rpm (rev/min)-120rpm, can measure value before the thickness of said a plurality of points so exactly.
In examples more of the present invention, like Fig. 3 and shown in Figure 4, said step C) can comprise:
C-1) can utilize the said wafer of rubbing head 100 clampings also said wafer is contacted with polishing pad 200, the center of wherein said wafer can be corresponding with said terminal point measurement mechanism so that confirm to measure initial point;
C-2) rubbing head 100 can rotation and rubbing head 100 can move back and forth so that said terminal point measurement mechanism is worth after can measuring the thickness of the said a plurality of points on the said wafer with respect to polishing pad 200, wherein polishing pad 200 can be static;
C-3) maximum in the value and the difference of minimum of a value behind the thickness of the said a plurality of points of calculating; If the difference of said maximum and said minimum of a value is not more than predetermined value; Then the surface finish thickness of said wafer is even, otherwise the surface finish of said wafer (difference that is said maximum and said minimum of a value is greater than said predetermined value) in uneven thickness; With
C-4) if the surface finish of said wafer is in uneven thickness; Can calculate the difference that is worth after the value and thickness before the thickness of said a plurality of points respectively so that obtain the thickness removal value of said a plurality of points, can carry out chemically mechanical polishing to said wafer according to the thickness removal value of said a plurality of points and be not more than said predetermined value (promptly even) until the surface finish thickness of said wafer until the difference of said maximum and said minimum of a value.
In most cases; Utilization according to the thickness of said a plurality of points before the CMP process confirmed of value (in other words; This CMP process is to confirm according to the thickness situation of the zones of different on the surface of said wafer) wafer is carried out chemically mechanical polishing, can obtain the uniform wafer of surface finish thickness.But under the effect of enchancement factor, the surface finish thickness of wafer maybe be inhomogeneous.Be worth after can utilizing said terminal point measurement mechanism to measure the thickness of the said a plurality of points on the said wafer after polishing.In other words, can on said wafer, choose a plurality of points, at the thickness that carries out a plurality of points of chemically mechanical polishing fore-and-aft survey.If the maximum behind the thickness of said a plurality of points in the value and the difference of minimum of a value are not more than said predetermined value, can think that then the surface finish thickness of said wafer is even.Said predetermined value can confirm that the said predetermined value in for example smart the throwing can be less than the said predetermined value in thick the throwing according to the status of chemically mechanical polishing in the whole manufacturing process of said wafer.Particularly, said predetermined value can be 100 nanometers.
If the surface finish of said wafer is in uneven thickness, then can calculate the difference that is worth after the value and thickness before the thickness of said a plurality of points respectively so that obtain the thickness removal value of said a plurality of points.Can be worth to come according to the thickness removal of said a plurality of points and confirm CMP process again, and can utilize and confirm that again CMP process carries out chemically mechanical polishing to said wafer once more so that make the surface finish thickness of said wafer even.How be worth to come and confirm that again CMP process is that those skilled in the art know, therefore no longer describe in detail according to the thickness removal of said a plurality of points.
If after carrying out chemically mechanical polishing once more, the surface finish thickness of said wafer still is inhomogeneous, can repeat said process, and is even until the surface finish thickness of said wafer.
In one embodiment of the invention, when after utilizing said terminal point measurement mechanism to measure the thickness of the said a plurality of points on the said wafer, being worth, the rubbing head 100 of the said wafer of clamping can be with respect to polishing pad 200 reciprocal translations, like this can be so that operation.Particularly, the rubbing head 100 of the said wafer of clamping can along polishing pad 200 radially with respect to polishing pad 200 reciprocal translations, can be convenient to more like this operation.Wherein, the stroke of said reciprocal translation can be 50mm-300mm, can make said a plurality of point be distributed in the whole burnishing surface of said wafer like this, thereby can know the thickness situation of zones of different on the surface of said wafer more all sidedly.Said reciprocating frequency can be 5 times/minute-40 times/minute, is worth after can measuring the thickness of said a plurality of points so exactly.Advantageously, the stroke of said reciprocal translation can be 100mm-150mm, and said reciprocating frequency can be 10 times/minute-30 times/minute, is worth after can measuring the thickness of said a plurality of points so more exactly.In a concrete example of the present invention, the rotating speed of rubbing head 100 can be 60rpm (rev/min)-120rpm, be worth after can measuring the thickness of said a plurality of points so exactly.
In said steps A-2) and said step C-2) in; The rotating speed of rubbing head 100 can be identical; And the reciprocating mode of rubbing head 100 (for example back and forth translation), stroke can be identical with frequency, can make said steps A-2 like this) in a plurality of measurement points (being said a plurality of point) and said step C-2) in a plurality of measurement points (being said a plurality of point) highly overlap.
It will be appreciated by persons skilled in the art that and when carrying out chemically mechanical polishing, can utilize polishing fluid conveying arm 300 that polishing fluid is transported on the polishing pad 200.After chemically mechanical polishing finishes, can also utilize 410 pairs of polishing pads 200 of finishing head of trimmer 400 to repair.Wherein, can be known according to the rubbing head that cmp method utilized 100 of the embodiment of the invention, polishing pad 200, polishing fluid conveying arm 300, trimmer 400, polishing disk, polishing fluid etc., therefore no longer describe in detail.
Utilization need not to re-use the on-line measurement device when according to the cmp method of the embodiment of the invention wafer being carried out chemically mechanical polishing; Thereby not only can simplify the structure of the chemical-mechanical polisher that carries out chemically mechanical polishing, the cost of reduction chemical-mechanical polisher widely, and can reduce the chemically mechanical polishing cost of wafer widely.
In the description of this specification, the description of reference term " embodiment ", " some embodiment ", " example ", " concrete example " or " some examples " etc. means the concrete characteristic, structure, material or the characteristics that combine this embodiment or example to describe and is contained at least one embodiment of the present invention or the example.In this manual, the schematic statement to above-mentioned term not necessarily refers to identical embodiment or example.And concrete characteristic, structure, material or the characteristics of description can combine with suitable manner in any one or more embodiment or example.
Although illustrated and described embodiments of the invention; Those having ordinary skill in the art will appreciate that: under the situation that does not break away from principle of the present invention and aim, can carry out multiple variation, modification, replacement and modification to these embodiment, scope of the present invention is limited claim and equivalent thereof.