EP0517595B1 - Polishing machine with pressure control - Google Patents
Polishing machine with pressure control Download PDFInfo
- Publication number
- EP0517595B1 EP0517595B1 EP19920401533 EP92401533A EP0517595B1 EP 0517595 B1 EP0517595 B1 EP 0517595B1 EP 19920401533 EP19920401533 EP 19920401533 EP 92401533 A EP92401533 A EP 92401533A EP 0517595 B1 EP0517595 B1 EP 0517595B1
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- EP
- European Patent Office
- Prior art keywords
- electromagnet
- polishing
- polishing plate
- sample
- polished
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 238000005498 polishing Methods 0.000 title claims description 64
- 230000005540 biological transmission Effects 0.000 claims 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 12
- 235000012431 wafers Nutrition 0.000 description 11
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- 239000000377 silicon dioxide Substances 0.000 description 6
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- UGKDIUIOSMUOAW-UHFFFAOYSA-N iron nickel Chemical compound [Fe].[Ni] UGKDIUIOSMUOAW-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000000429 assembly Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- HIGRAKVNKLCVCA-UHFFFAOYSA-N alumine Chemical compound C1=CC=[Al]C=C1 HIGRAKVNKLCVCA-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 238000004377 microelectronic Methods 0.000 description 2
- 238000005459 micromachining Methods 0.000 description 2
- 230000036515 potency Effects 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 235000019589 hardness Nutrition 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005088 metallography Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/27—Work carriers
- B24B37/30—Work carriers for single side lapping of plane surfaces
Definitions
- the present invention relates to a polishing machine with pressure control.
- the invention finds a particular application in the polishing of microelectronic components integrated in semiconductor wafers (in silicon for example). They can be, in particular, magnetic writing and reading heads.
- the first document relates to heads with a so-called “horizontal” structure -car formed from a stack of layers deposited on the upper face of a semiconductor wafer -and the second to heads with a structure called “vertical” -car formed from layers deposited on the edge of such a wafer.
- micro-machining carried out on such wafers consists, in the first case, in leveling (or “planarizing") and in polishing various intermediate sub-assemblies obtained during the production process, in defining an air gap and in bringing the assembly of the head in the general plane of the substrate, also called the flight plane.
- the purpose of micro-machining is to define an air gap and to adjust the shape of the flight pads.
- the machine object of this The invention is above all intended for polishing assemblies or sub-assemblies corresponding to the first category (horizontal heads), because it is in this case that the technological problems are the most difficult.
- Figure 1 shows, by way of example of a polishing piece, a magnetic writing and reading head in a horizontal structure.
- the assembly shown corresponds, at the last stage of production, just before final polishing.
- This assembly includes a silicon substrate 10 in which a box has been etched, a magnetic circuit 12 made of iron-nickel alloy, a double coil 14 made of copper, a layer of silica 16 3 to 6 ⁇ m thick, a non-magnetic spacer 18 in silica approximately 1 ⁇ m thick and two upper pole pieces 20 in iron-nickel.
- the final polishing plan is marked in broken lines and referenced 22.
- the material removal relates to the pole pieces 20 and to the protrusions 23 in silica. In order not to alter the magnetic circuit, this removal must not reduce the thickness of the uniform layer of silica by more than 0.3 ⁇ m.
- the final polishing plan defines the flight plan of the head.
- Two such heads are generally placed side by side on two parallel strips called "skis", defining two flight plans, in a general catamaran structure.
- this system is complex due because the electromagnet is placed in a rotating block, it does not allow the pressure to be controlled at very low values, since at least this pressure is that exerted by the whole of the sample support block. This system therefore makes it possible to control only an increase in pressure, compared to a minimum pressure.
- Document EP-A-0 284 343 describes one, which comprises an inflatable balloon capable of quickly absorbing the variations in pressure exerted on the sample to be polished due to variations in the contours of the polishing tool. But this machine does not allow to control the polishing pressure.
- the sample is assumed to be held by a support piece placed above the polishing plate.
- the force is applied to the sample via the support head and the polishing plate is fixed.
- the invention is equally applicable to a machine where the polishing sample is located below the polishing tool on a sample support table, the polishing tool being held by the support head on which pressure is exerted.
- the invention relates essentially to the means represented schematically by the block 34.
- the machine shown in Figures 3a (side view) and 3b (end view) comprises a rigid bracket 50 sliding on vertical columns 52 and 54.
- An electromagnet 56 is powered by means 58.
- This electromagnet is fixed at one end of the stem 50, and is provided with a movable axial rod 60.
- This rod is equipped with a pressure sensor 62 having an outlet 64 connected to a pressure display means 65 and to the supply means 58.
- the pressure sensor 62 (or the display means 65) is connected to a comparator 67 also receiving a setpoint signal from a generator 69.
- the output of the comparator delivers an error signal equal to the difference, in magnitude and as a sign, between the pressure measured by the sensor and the pressure setpoint.
- the electromagnet 56 is then controlled so that the error signal is canceled.
- An arm 70 is mounted oscillating around two horizontal axes 72-74 integral with the bracket 50.
- a spindle 80 supports, at its lower part, an adjustable eccentric 82 provided with a means 84 for hooking the sample support head 86.
- This spindle is equipped, at its upper part, with a stop 90, for example a ball stop.
- the pin 80 is fixed to the end of the arm, under the electromagnet 56.
- the axial rod 60 of this electromagnet and its pressure sensor 62 come to bear on the stop 90.
- a motor 91 is arranged at the other end of the arm 70 and forms a counterweight.
- a balancing mass 92 adjustable in position, is disposed near the motor 91 and is capable of balancing the arm 70 in the position of the latter.
- a means 93 for transmitting movement for example a toothed belt, is arranged between the motor 91 and the eccentric 82 to control the rotation of the eccentric 82.
- Means 94, 95 are provided for vertically moving the bracket and all the means attached thereto, along the vertical columns 52, 54 until the sample is brought near the polishing plate 30.
- the stem At rest, the stem is in high stop; the swinging arm is then slightly inclined (figure a); the ball stop is supported on the rod of the electromagnet; the pressure display 65 indicates substantially zero.
- the sample holder 86 is hooked to the eccentric; the swinging arm 70 swings down; we find the equilibrium position (sensor at zero) by moving the balancing mass 92 (figure b).
- the stem descends along the axes 52-54 and is locked in the low position by the jacks (figure c).
- the oscillating arm 70 is always inclined very slightly upwards and the sample holder is approximately one millimeter from the abrasive plane 30.
- the electromagnet 56 is then supplied with an adjustable and stable direct voltage, until the sample comes into contact with the polishing plane. Then the load is increased to the desired force value (figure d). Polishing can then be carried out by controlling the motor 91.
- This device makes it possible to adjust and control the polishing pressure from an almost zero value to a maximum value fixed by the electromagnet chosen from 0 to 100 kg for example.
- FIG. 5 shows, in section, a sub-assembly corresponding to a magnetic writing and reading head in a horizontal structure, of the kind which has already been mentioned in connection with FIG. 1.
- the sub-assembly of FIG. 5 essentially comprises a silicon substrate 100, two edges of the casing 102 in silica, two vertical pads 104 in iron-nickel. This involves polishing this sub-assembly according to a plane 106 before continuing the operations of forming the upper pole piece.
- the profile of the sub-assembly is shown in part a of Figure 6.
- the entire recorded interval measures 1.2 mm (the units indicated are therefore in micrometers).
- the units are in hundreds of nanometers.
- the profile presents the shape of part b of FIG. 6.
- the whole of the raised interval measures 4 mm (which means that the survey relates to the entire "ski" carrying the head).
- the scale is in ten nanometers.
- the residual overshoot in the natural curvature of the "ski” is less than or equal to 30 nm (this curvature being a fraction of the deformation of the substrate).
- FIG. 7 shows the head after the operations for forming the non-magnetic spacer 110 and the upper pole pieces 112 made of iron-nickel. Reliefs 114 appear in the center of the head. The final polishing plan is referenced 116.
- Part b of Figure 8 shows the reading after polishing. On the abscissa, the units are still in micrometers and on the ordinate, in tens of nanometers. No residual overshoot is detected, we only measure the natural curvature of the pad (this curvature being a fraction of the deformation of the substrate).
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
Description
La présente invention a pour objet une machine de polissage à contrôle de pression.The present invention relates to a polishing machine with pressure control.
L'invention trouve une application particulière au polissage de composants microélectroniques intégrés dans des plaquettes de semiconducteur (en silicium par exemple). Il peut s'agir, notamment, de têtes magnétiques d'écriture et de lecture.The invention finds a particular application in the polishing of microelectronic components integrated in semiconductor wafers (in silicon for example). They can be, in particular, magnetic writing and reading heads.
Des procédés de réalisation de telles têtes sont décrites dans de nombreux documents et notamment dans US-A-4,837,924 et US-A-4,333,229. Le premier document se rapporte à des têtes à structure dite "horizontale" -car formée d'un empilement de couches déposées sur la face supérieure d'une plaquette semiconductrice-et le second à des têtes à structure dite "verticale" -car formée de couches déposées sur la tranche d'une telle plaquette-.Methods for producing such heads are described in numerous documents and in particular in US-A-4,837,924 and US-A-4,333,229. The first document relates to heads with a so-called "horizontal" structure -car formed from a stack of layers deposited on the upper face of a semiconductor wafer -and the second to heads with a structure called "vertical" -car formed from layers deposited on the edge of such a wafer.
Les micro-usinages effectués sur de telles plaquettes consistent, dans le premier cas, à niveler (ou "planariser") et à polir divers sous-ensembles intermédiaires obtenus au cours du procédé de réalisation, à définir un entrefer et à amener l'ensemble de la tête dans le plan général du substrat, dit encore plan de vol.The micro-machining carried out on such wafers consists, in the first case, in leveling (or "planarizing") and in polishing various intermediate sub-assemblies obtained during the production process, in defining an air gap and in bringing the assembly of the head in the general plane of the substrate, also called the flight plane.
Dans le second cas, les micro-usinages ont pour but de définir un entrefer et d'ajuster la forme des patins de vol.In the second case, the purpose of micro-machining is to define an air gap and to adjust the shape of the flight pads.
Bien que pouvant s'appliquer éventuellement à la réalisation de têtes de la deuxième catégorie (têtes verticales), la machine objet de la présente invention est avant tout destinée au polissage d'ensembles ou sous-ensembles correspondants à la première catégorie (têtes horizontales), car c'est dans ce cas que les problèmes technologiques sont les plus ardus.Although possibly applicable to the production of heads of the second category (vertical heads), the machine object of this The invention is above all intended for polishing assemblies or sub-assemblies corresponding to the first category (horizontal heads), because it is in this case that the technological problems are the most difficult.
La figure 1 montre, à titre d'exemple de pièce à polir, une tête magnétique d'écriture et de lecture en structure horizontale. L'ensemble représenté correspond, à la dernière étape de réalisation, juste avant polissage final. Cet ensemble comprend un substrat de silicium 10 dans lequel un caisson a été gravé, un circuit magnétique 12 en alliage fer-nickel, un double bobinage 14 en cuivre, une couche en silice 16 de 3 à 6µm d'épaisseur, un espaceur amagnétique 18 en silice de 1µm d'épaisseur environ et deux pièces polaires supérieures 20 en fer-nickel. Le plan de polissage final est marqué en trait interrompu et référencé 22.Figure 1 shows, by way of example of a polishing piece, a magnetic writing and reading head in a horizontal structure. The assembly shown corresponds, at the last stage of production, just before final polishing. This assembly includes a
L'enlèvement de matière porte sur les pièces polaires 20 et sur les dépassements 23 en silice. Pour ne pas altérer le circuit magnétique, cet enlèvement ne doit pas diminuer l'épaisseur de la couche uniforme de silice de plus de 0,3µm. Le plan final de polissage définit le plan de vol de la tête.The material removal relates to the
Deux telles têtes sont généralement disposées côte à côte sur deux bandes parallèles dites "skis", définissant deux plans de vol, dans une structure générale en catamaran.Two such heads are generally placed side by side on two parallel strips called "skis", defining two flight plans, in a general catamaran structure.
Le polissage, qui consiste en un enlèvement de matière en très petite quantité, est une opération bien connue. On la rencontre en métallographie, en optique et en microélectronique. L'une ou l'autre des deux techniques suivantes est utilisée :
- la rectification à l'outil diamanté : il s'agit d'un usinage dans lequel on forme un "copeau" semi-continu ou continu par deux mouvements combinés relatifs entre l'outil et la pièce à usiner (un mouvement d'avance et un mouvement de coupe) ;
- le rodage et polissage : il s'agit d'une abrasion plus ou moins fine (ou écrouissage) et contrôlée de la surface par frottement sur des disques très variés non abrasifs par nature, sur lesquels on apporte un abrasif en pâte ou en solution aqueuse ; une variante consiste à placer, sur un plateau de polissage rotatif, un disque de film abrasif et à arroser celui-ci lors du polissage avec un liquide pour refroidir la pièce et éviter l'encrassement.
- grinding with a diamond tool : it it is a machining in which a semi-continuous or continuous "chip" is formed by two relative combined movements between the tool and the workpiece (a feed movement and a cut movement);
- lapping and polishing: this is a more or less fine abrasion (or hardening) and controlled of the surface by friction on very varied discs non abrasive by nature, on which an abrasive is applied in paste or in aqueous solution ; a variant consists in placing, on a rotary polishing plate, a disc of abrasive film and in spraying the latter during polishing with a liquid to cool the part and avoid fouling.
Le polissage des plaquettes semiconductrices comprenant un très grand nombre de microcomposants intégrés pose des problèmes particuliers :
- tout d'abord, la plaquette est déformée et déformable,
- par ailleurs, le rodage doit affecter simultanément plusieurs matériaux de duretés très différentes : silice, alumine, alliage alumine/carbure de titane, alliage fer/nickel,
- les pièces à roder sont de surfaces très petites par rapport à la plaquette de silicium,
- enfin, il s'agit d'usiner, dans leur épaisseur, des couches déposées sur une plaquette, et généralement, il faut polir simultanément 600 excroissances correspondant à 600 têtes magnétiques, en dépassement de quelques microns, et cela avec une précision de l'ordre du nanomètre, sans diminuer l'épaisseur de la couche mince qui recouvre la plaquette de plus de 200 à 300nm.
- first of all, the plate is deformed and deformable,
- in addition, running-in must simultaneously affect several materials with very different hardnesses: silica, alumina, alumina / titanium carbide alloy, iron / nickel alloy,
- the parts to be lapped have very small surfaces compared to the silicon wafer,
- finally, it involves machining, in their thickness, layers deposited on a wafer, and generally, it is necessary to simultaneously polish 600 protuberances corresponding to 600 magnetic heads, in excess of a few microns, and this with an accuracy of the order of a nanometer, without reducing the thickness of the thin layer which covers the wafer by more than 200 to 300nm.
Les machines de polissage connues ne permettent pas de satisfaire à toutes ces exigences. L'une des raisons de cette incapacité est que la pression exercée sur la pièce à polir n'est pas contrôlée avec suffisamment de précision tout au long du polissage.Known polishing machines do not meet all of these requirements. One of the reasons for this incapacity is that the pressure exerted on the workpiece is not controlled with sufficient precision throughout the polishing.
Il faut comprendre que ce problème de contrôle de pression est particulièrement difficile à résoudre car si la machine doit être capable de travailler avec des pressions relativement importantes (de 5 à 40 kg) elle doit aussi pouvoir travailler avec des valeurs très basses (de 0,1 à 0,5 kg). En effet, lors du polissage de plaquettes de silicium contenant des circuits intégrés, le début de l'opération de polissage s'effectue sur des dépassements (ou reliefs) parfois très hauts et très étroits (comme on le comprendra mieux en liaison avec les figures 5 à 8 qui seront décrites ultérieurement). Ces dépassements sont très fragiles. Aussi convient-il de les traiter avec des pressions très faibles. Cependant, en fin de polissage, il faut des pressions très importantes pour éviter toute perte de contact entre la plaquette et le film abrasif et ainsi obtenir la polarisation parfaite souhaitée.It should be understood that this pressure control problem is particularly difficult to solve because if the machine must be able to work with relatively high pressures (from 5 to 40 kg) it must also be able to work with very low values (from 0, 1 to 0.5 kg). Indeed, when polishing silicon wafers containing integrated circuits, the start of the polishing operation is carried out on overshoots (or reliefs) sometimes very high and very narrow (as will be better understood in connection with the figures 5 to 8 which will be described later). These overruns are very fragile. It is therefore advisable to treat them with very low pressures. However, at the end of polishing, very high pressures are required to avoid any loss of contact between the wafer and the abrasive film and thus obtain the perfect polarization desired.
La présente invention a justement pour but de remédier à cet inconvénient. A cette fin, l'invention propose une machine qui, tout d'abord, et comme toutes les machines de polissage comprend :
- un plateau de polissage,
- un moyen apte à maintenir un échantillon, face à polir en regard du plateau de polissage,
- des moyens pour exercer une force d'application de la face à polir sur le plateau de polissage et pour déplacer transversalement l'échantillon à polir par rapport au plateau de polissage,
- a polishing plate,
- a means capable of maintaining a sample, face to be polished opposite the polishing plate,
- means for exerting an application force of the face to be polished on the polishing plate and for transversely moving the sample to be polished relative to the polishing plate,
Par ces moyens il est possible d'équilibrer parfaitement la machine pour que la pression exercée sur l'échantillon soit d'abord nulle, à partir de quoi il est possible d'ajuster et d'asservir la pression à toute valeur faible ou forte, par action sur l'électroaimant.By these means it is possible to perfectly balance the machine so that the pressure exerted on the sample is first zero, from which it is possible to adjust and control the pressure at any low or high value, by action on the electromagnet.
On observera qu'il est déjà connu d'utiliser un électroaimant pour régler une pression de polissage. Par exemple, le document PATENT ABSTRACTS OF JAPAN vol. 14, n° 107, (M-942) 27 février 1990 (JP-A-1 310 859) décrit une machine de polissage comprenant un bloc support d'échantillons, ce bloc étant mis en rotation. Ce bloc, par son propre poids, crée une certaine pression sur les échantillons. Il est prévu en outre, à l'intérieur du bloc support, un électroaimant permettant d'augmenter encore la pression.It will be observed that it is already known to use an electromagnet to regulate a polishing pressure. For example, the document PATENT ABSTRACTS OF JAPAN vol. 14, No. 107, (M-942) February 27, 1990 (JP-A-1 310 859) describes a polishing machine comprising a sample support block, this block being rotated. This block, by its own weight, creates a certain pressure on the samples. There is also provided, inside the support block, an electromagnet to further increase the pressure.
Outre que ce système est complexe en raison de ce que l'électroaimant est disposé dans un bloc en rotation, il ne permet pas d'asservir la pression à de très faibles valeurs, puisqu'au minimum cette pression est celle exercée par l'ensemble du bloc support d'échantillons. Ce système ne permet donc d'asservir qu'un accroissement de pression, par rapport à une pression minimale.Besides that this system is complex due because the electromagnet is placed in a rotating block, it does not allow the pressure to be controlled at very low values, since at least this pressure is that exerted by the whole of the sample support block. This system therefore makes it possible to control only an increase in pressure, compared to a minimum pressure.
Il existe aussi des machines de polissage à bras équilibré. Le document EP-A-0 284 343 en décrit une, qui comprend un ballon gonflable apte à encaisser rapidement les variations de pression exercée sur l'échantillon à polir en raison des variations de contours de l'outil de polissage. Mais cette machine ne permet pas d'asservir la pression de polissage.There are also balanced arm polishing machines. Document EP-A-0 284 343 describes one, which comprises an inflatable balloon capable of quickly absorbing the variations in pressure exerted on the sample to be polished due to variations in the contours of the polishing tool. But this machine does not allow to control the polishing pressure.
Si l'on voulait combiner ces deux documents, cela conduirait à une machine dans laquelle la tête porte-échantillons elle-même serait équipée d'un électroaimant, celui étant disposé sous l'extrémité du bras équilibré. Le bras articulé devrait donc soutenir cet électroaimant ce qui poserait des problèmes mécaniques sérieux. Par ailleurs, une augmentation de pression par action sur l'électroaimant aurait en réalité pour effet de comprimer le ballon gonflable, ce qui annulerait l'effet recherché, le rôle du ballon étant précisément de compenser les variations de pression.If we wanted to combine these two documents, this would lead to a machine in which the sample-holder head itself would be equipped with an electromagnet, that being placed under the end of the balanced arm. The articulated arm should therefore support this electromagnet which would pose serious mechanical problems. Furthermore, an increase in pressure by action on the electromagnet would actually have the effect of compressing the inflatable balloon, which would cancel the desired effect, the role of the balloon being precisely to compensate for variations in pressure.
Ainsi, la combinaison de ces deux documents est-elle inopérante et de toute façon ne conduit pas à la machine de la prèsente invention où l'électroaimant est placé au-dessus de la tête support, à l'extrémité d'une potence rigide, le bras monté oscillant ne supportant que les moyens de déplacement de la tête support. Ainsi, une pression aussi faible que désirée peut être obtenue et asservie.Thus, the combination of these two documents is ineffective and in any case does not lead to the machine of the present invention where the electromagnet is placed above the support head, at the end of a rigid bracket, the oscillating mounted arm supporting only the means for moving the support head. Thus, a pressure as low as desired can be obtained and controlled.
De toute façon, les caractéristiques et avantages de l'invention apparaîtront mieux à la lumière de la description qui va suivre. Cette description porte sur des exemples de réalisation donnés à titre explicatif et nullement limitatif et se réfère à des dessins annexés, sur lesquels :
- la figure 1, déjà décrite, montre un exemple de pièce à polir correspondant à une tête magnétique d'écriture et de lecture,
- la figure 2 montre la structure générale d'une machine à polir selon l'invention,
- les figures 3a et 3b montrent en détail une machine conforme à l'invention avec ses moyens pour exercer une pression contrôlée sur la tête support et pour déplacer cette tête,
- la figure 4 montre quatre positions de ces différents moyens et illustre le principe de mise en place de la tête support avec contrôle de la pression,
- la figure 5 montre un sous-ensemble intermédiaire dans la réalisation d'une tête magnétique d'écriture et de lecture,
- la figure 6 montre le profil de ce sous-ensemble avant et après polissage,
- la figure 7 montre la tête magnétique terminée,
- la figure 8 montre le profil de cette tête avant et après polissage.
- FIG. 1, already described, shows an example of a polishing piece corresponding to a magnetic writing and reading head,
- FIG. 2 shows the general structure of a polishing machine according to the invention,
- FIGS. 3a and 3b show in detail a machine in accordance with the invention with its means for exerting controlled pressure on the support head and for moving this head,
- FIG. 4 shows four positions of these different means and illustrates the principle of positioning the support head with pressure control,
- FIG. 5 shows an intermediate sub-assembly in the production of a magnetic writing and reading head,
- FIG. 6 shows the profile of this sub-assembly before and after polishing,
- FIG. 7 shows the completed magnetic head,
- Figure 8 shows the profile of this head before and after polishing.
Dans l'exemple qui va être décrit, l'échantillon est supposé tenu par une pièce support disposée au-dessus du plateau de polissage. Dans ce cas, la force est appliquée sur l'échantillon par l'intermédiaire de la tête support et le plateau de polissage est fixe. Mais l'invention s'applique tout aussi bien à une machine où l'échantillon à polir serait situé en dessous de l'outil de polissage sur une table support d'échantillon, l'outil de polissage étant tenu par la tête support sur laquelle s'exerce alors la pression.In the example which will be described, the sample is assumed to be held by a support piece placed above the polishing plate. In this case, the force is applied to the sample via the support head and the polishing plate is fixed. However, the invention is equally applicable to a machine where the polishing sample is located below the polishing tool on a sample support table, the polishing tool being held by the support head on which pressure is exerted.
La machine représentée sur la figure 2 comprend, schématiquement :
- un plateau de polissage fixe 30,
- des moyens 34 pour exercer une force F sur la tête
support 32 afin d'appliquer l'échantillon 44 à polir sur le plateau de polissage 30 et pour déplacer transversalement la tête desupport 32 par rapport au plateau fixe 30, ce moyen pouvant comprendreun excentrique 37.
- a
fixed polishing plate 30, - means 34 for exerting a force F on the
support head 32 in order to apply the sample 44 to be polished on the polishingplate 30 and for transversely moving thesupport head 32 relative to the fixedplate 30, this means possibly comprising a eccentric 37.
L'invention porte essentiellement sur les moyens représentés schématiquement par le bloc 34.The invention relates essentially to the means represented schematically by the block 34.
La machine représentée sur les figures 3a (vue de profil) et 3b (vue en bout) comprend une potence rigide 50 coulissant sur des colonnes verticales 52 et 54. Un électroaimant 56 est alimenté par des moyens 58. Cet électroaimant est fixé à une extrémité de la potence 50, et est muni d'une tige axiale mobile 60. Cette tige est équipée d'un capteur de pression 62 ayant une sortie 64 reliée à un moyen d'affichage de la pression 65 et aux moyens d'alimentation 58.The machine shown in Figures 3a (side view) and 3b (end view) comprises a
Le capteur de pression 62 (ou le moyen d'affichage 65) est relié à un comparateur 67 recevant également un signal de consigne provenant d'un générateur 69. La sortie du comparateur délivre un signal d'erreur égal à la différence, en grandeur et en signe, entre la pression mesurée par le capteur et la pression de consigne. L'électroaimant 56 est alors commandé de telle sorte que le signal d'erreur s'annule.The pressure sensor 62 (or the display means 65) is connected to a
Un bras 70 est monté oscillant autour de deux axes horizontaux 72-74 solidaires de la potence 50. Une broche 80 supporte, à sa partie inférieure, un excentrique réglable 82 muni d'un moyen 84 d'accrochage de la tête support d'échantillon 86. Cette broche est équipée, à sa partie supérieure, d'une butée 90, par exemple une butée à bille. La broche 80 est fixée à l'extrémité du bras, sous l'électroaimant 56. La tige axiale 60 de cet électroaimant et son capteur de pression 62 viennent prendre appui sur la butée 90.An
Un moteur 91 est disposé à l'autre extrémité du bras 70 et forme contrepoids. Une masse d'équilibrage 92, réglable en position, est disposé à proximité du moteur 91 et est apte à équilibrer le bras 70 en position de ce dernier.A
Un moyen 93 de transmission de mouvement, par exemple une courroie crantée, est disposée entre le moteur 91 et l'excentrique 82 pour commander la rotation de l'excentrique 82.A means 93 for transmitting movement, for example a toothed belt, is arranged between the
Des moyens 94, 95, par exemple des vérins, sont prévus pour déplacer verticalement la potence et tous les moyens qui y sont fixés, le long des colonnes verticales 52, 54 jusqu'à amener l'échantillon à proximité du plateau de polissage 30.Means 94, 95, for example jacks, are provided for vertically moving the bracket and all the means attached thereto, along the
La figure 4 permet de mieux comprendre le fonctionnement de cette machine.Figure 4 provides a better understanding of how this machine works.
Au repos, la potence se trouve en butée haute ; le bras oscillant se trouve alors légérement incliné (figure a) ; la butée à bille est en appui sur la tige de l'électroaimant ; l'afficheur de pression 65 indique sensiblement zéro.At rest, the stem is in high stop; the swinging arm is then slightly inclined (figure a); the ball stop is supported on the rod of the electromagnet; the
On accroche le porte-échantillon 86 à l'excentrique ; le bras oscillant 70 bascule vers le bas ; on retrouve la position d'équilibre (capteur à zéro) en déplaçant la masse d'équilibrage 92 (figure b).The
La potence descend le long des axes 52-54 et se trouve verrouillée en position basse par les vérins (figure c).The stem descends along the axes 52-54 and is locked in the low position by the jacks (figure c).
Dans cette configuration, le bras oscillant 70 est toujours incliné très légèrement vers le haut et le support d'échantillon est à environ un millimètre du plan abrasif 30.In this configuration, the
On alimente alors l'électroaimant 56 par une tension continue réglable et stable, jusqu'à ce que l'échantillon vienne au contact du plan de polissage. Puis on augmente la charge jusqu'à la valeur d'effort souhaitée (figure d). Le polissage peut alors s'effectuer par la commande du moteur 91.The
Ce dispositif permet de régler et de contrôler la pression de polissage depuis une valeur quasi nulle jusqu'à une valeur maximum fixée par l'électroaimant choisi de 0 à 100kg par exemple.This device makes it possible to adjust and control the polishing pressure from an almost zero value to a maximum value fixed by the electromagnet chosen from 0 to 100 kg for example.
La machine qui vient d'être décrite peut être avantageusement combinée à des dispositions prévues dans trois autres demandes de brevets européens déposées par le présent Demandeur, le jour même du dépôt de la présente demande, et qui sont intitulées respectivement :
- "Procédé de réalisation d'un outil de polissage et outil obtenu par ce procédé",
- "Machine de polissage à bande microabrasive tendue et à tête support perfectionnée",
- "Machine de polissage à table porte-échantillon perfectionnée".
- "Process for producing a polishing tool and tool obtained by this process",
- "Polishing machine with stretched microabrasive band and improved support head",
- "Table polishing machine improved sample holder ".
Avec la machine de polissage qui vient d'être décrite, équipée d'une tête support de plaquettes perfectionnée, et d'une feuille microabrasive tendue sur le plateau de polissage, le Demandeur a obtenu des résultats remarquables qui sont illustrés sur les figures 5 à 8.With the polishing machine which has just been described, equipped with an improved wafer support head, and a microabrasive sheet stretched over the polishing plate, the Applicant has obtained remarkable results which are illustrated in FIGS. 5 to 8.
La figure 5 montre, en coupe, un sous-ensemble correspondant à une tête magnétique d'écriture et de lecture en structure horizontale, du genre de celle qui a été déjà évoquée à propos de la figure 1. Le sous-ensemble de la figure 5 comprend essentiellement un substrat en silicium 100, deux bords de caisson 102 en silice, deux plots verticaux 104 en fer-nickel. Il s'agit de polir ce sous-ensemble selon un plan 106 avant de poursuivre les opérations de formation de la pièce polaire supérieure.FIG. 5 shows, in section, a sub-assembly corresponding to a magnetic writing and reading head in a horizontal structure, of the kind which has already been mentioned in connection with FIG. 1. The sub-assembly of FIG. 5 essentially comprises a
Avant polissage, le profil du sous-ensemble est représenté sur la partie a de la figure 6. En abscisses, la totalité de l'intervalle relevé mesure 1,2 mm (les unités indiquées sont donc en micromètres). En ordonnées, les unités sont en centaines de nanomètres. On voit nettement, sur ce relevé, les deux bords du caisson et, au centre, les deux plots verticaux en fer-nickel.Before polishing, the profile of the sub-assembly is shown in part a of Figure 6. On the abscissa, the entire recorded interval measures 1.2 mm (the units indicated are therefore in micrometers). On the ordinate, the units are in hundreds of nanometers. We can clearly see, on this statement, the two edges of the box and, in the center, the two vertical iron-nickel studs.
Après polissage, le profil prèsente la forme de la partie b de la figure 6. La totalité de l'intervalle relevé mesure 4 mm (ce qui signifie que le relevé porte sur la totalité du "ski" portant la tête). En ordonnées, l'échelle est en dizaine de nanomètres. Le dépassement résiduel dans la courbure naturelle du "ski" est inférieur ou égal à 30 nm (cette courbure étant une fraction de la déformation du substrat).After polishing, the profile presents the shape of part b of FIG. 6. The whole of the raised
La figure 7 montre la tête après les opérations de formation de l'espaceur amagnétique 110 et des pièces polaires supérieures 112 en fer-nickel. Des reliefs 114 apparaissent au centre de la tête. Le plan final de polissage est référencé 116.FIG. 7 shows the head after the operations for forming the
Sur la partie a de la figure 8, on voit le profil de ce sous-ensemble avant rodage. Les unités sont les mêmes que pour la figure 6a : 1,2 mm pour la totalité de l'axe des abscisses et centaines de nanomètres en ordonnées. Les trois pics correspondants aux trois reliefs des pièces polaires sont bien visibles.On part a of FIG. 8, we see the profile of this sub-assembly before running in. The units are the same as for FIG. 6a: 1.2 mm for the entire abscissa axis and hundreds of nanometers on the ordinate. The three peaks corresponding to the three reliefs of the pole pieces are clearly visible.
La partie b de la figure 8 montre le relevé après polissage. En abscisses, les unités sont encore en micromètres et en ordonnées, en dizaines de nanomètres. Aucun dépassement résiduel n'est détecté, on ne mesure que la courbure naturelle du patin (cette courbure étant une fraction de la déformation du substrat).Part b of Figure 8 shows the reading after polishing. On the abscissa, the units are still in micrometers and on the ordinate, in tens of nanometers. No residual overshoot is detected, we only measure the natural curvature of the pad (this curvature being a fraction of the deformation of the substrate).
Claims (3)
- Polishing machine comprising:- a polishing plate (30),- a means (32) capable of keeping the samples (44) to be polished with their face to be polished facing the polishing plate (30),- means (34) for exerting a force for applying the face to be polished onto the polishing plate (30) and for transversely displacing the sample to be polished relative to the stationary polishing plate (30),this machine being characterized in that the said means for exerting the application force and for displacing the sample relative to the polishing plate comprise:- a rigid bracket (50) sliding on vertical posts (52, 54),- an electromagnet (56) and its supply means (58), the electromagnet being fixed to one end of the bracket (50), this electromagnet being equipped with a movable axial rod (60), this rod being equipped with a pressure sensor (62) having one output (64) connected to the means (58) for supplying the electromagnet (56),- a comparator (67) with two inputs which are respectively connected to the pressure sensor (62) and to a reference value generator (69), and having one output connected to the supply circuit (58) of the electromagnet (56),- an arm (70) mounted so that it can pivot about two horizontal pins (72-74) integral with the bracket (50),- a spindle (80) supporting, at its lower part, an adjustable eccentric (82) equipped with a means (84) for fastening a support head and equipped, at its upper part, with a limit stop (90), this spindle (80) being fixed to one end of the arm, beneath the electromagnet (56) fixed to the bracket (50), the axial rod (60) of this electromagnet and its pressure sensor (62) coming to bear on the limit stop (90) of the spindle (80),- a motor (91) located at the other end of the arm (70) and forming a counterweight,- a balancing mass (92) which is adjustable in terms of position and located close to the motor (91) capable of balancing the arm (70) in a substantially horizontal position,- a means (93) for the transmission of movement between the motor (91) and the eccentric (82) for making the eccentric (82) supported by the spindle (80) rotate,- means (94-95) for vertically displacing the bracket and all the means which are fixed thereto along the vertical posts (52, 54) until the sample (86) is brought into contact with the polishing plate (30).
- Machine according to Claim 1, characterized in that the support head supports the sample to be polished, the polishing plate being situated beneath the support head.
- Machine according to Claim 1, characterized in that the support head supports the polishing plate, the sample to be polished being situated beneath the support head.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9106867A FR2677291B1 (en) | 1991-06-06 | 1991-06-06 | PRESSURE CONTROL POLISHING MACHINE. |
FR9106867 | 1991-06-06 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0517595A1 EP0517595A1 (en) | 1992-12-09 |
EP0517595B1 true EP0517595B1 (en) | 1995-09-06 |
Family
ID=9413542
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19920401533 Expired - Lifetime EP0517595B1 (en) | 1991-06-06 | 1992-06-04 | Polishing machine with pressure control |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0517595B1 (en) |
DE (1) | DE69204558T2 (en) |
FR (1) | FR2677291B1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ES2137459T3 (en) | 1994-08-09 | 1999-12-16 | Ontrak Systems Inc | LINEAR POLISHING AND METHOD FOR PLANNING SEMICONDUCTIVE PILLS. |
US5593344A (en) * | 1994-10-11 | 1997-01-14 | Ontrak Systems, Inc. | Wafer polishing machine with fluid bearings and drive systems |
US6083082A (en) * | 1999-08-30 | 2000-07-04 | Lam Research Corporation | Spindle assembly for force controlled polishing |
CN106475885A (en) * | 2016-10-24 | 2017-03-08 | 无锡市明骥智能机械有限公司 | Workpiece polishing mechanism |
CN107081669B (en) * | 2017-05-22 | 2019-05-24 | 山东鲁发橡塑制品集团有限公司 | A kind of plastic parts burnishing device |
CN112605848A (en) * | 2020-11-29 | 2021-04-06 | 厦门理工学院 | Electromagnetic polishing disk mechanism with adjustable gravity center and polishing method |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2539561A (en) * | 1946-12-13 | 1951-01-30 | John M Wolfskill | Piezoelectric crystal lapping apparatus |
US2799974A (en) * | 1954-05-14 | 1957-07-23 | Corning Glass Works | Polishing apparatus |
JPS6090668A (en) * | 1983-10-19 | 1985-05-21 | Seiko Epson Corp | Mirror surface polishing method |
DE3520713A1 (en) * | 1985-06-10 | 1986-12-11 | Fa. Peter Wolters, 2370 Rendsburg | CONTROL DEVICE FOR MACHINING PRESSURE ON LAEPP, HONING AND POLISHING MACHINES |
US4811522A (en) * | 1987-03-23 | 1989-03-14 | Gill Jr Gerald L | Counterbalanced polishing apparatus |
CH684321A5 (en) * | 1988-04-07 | 1994-08-31 | Arthur Werner Staehli | Device on a double disk. |
JPH01310859A (en) * | 1988-06-09 | 1989-12-14 | Toyoda Mach Works Ltd | Polishing machining device |
-
1991
- 1991-06-06 FR FR9106867A patent/FR2677291B1/en not_active Expired - Fee Related
-
1992
- 1992-06-04 DE DE1992604558 patent/DE69204558T2/en not_active Expired - Fee Related
- 1992-06-04 EP EP19920401533 patent/EP0517595B1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
FR2677291B1 (en) | 1995-12-15 |
DE69204558T2 (en) | 1996-04-18 |
FR2677291A1 (en) | 1992-12-11 |
DE69204558D1 (en) | 1995-10-12 |
EP0517595A1 (en) | 1992-12-09 |
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