JPH1170460A - Flattening and polishing method and device for wiring circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly polish and remove the whole surface by measuring a pressure distribution acting on a contact face to be polished in polishing a wiring circuit board and by adjusting the pressurizing force on the contact face to be polished of the wiring circuit board into a uniform surface pressure distribution based on the pressure distribution. SOLUTION: A pressure difference is generated between a polishing sheet 35 and the contact face to be polished of a glass substrate 11 by the difference in extension of each presser element 14. The difference in the repulsive force of the each presser element 14 is detected by a pressure sensitive sensor 13 and the pressure signal is sent to a data processing circuit part 16 in the rear side of a plate member 17 via a lead wire 181. The operation voltage of each presser element 14 is changed so as to set each place to a prescribed pressure so that the forward/retreat of the presser element is driven. A substrate glass 11 can be pressurized against the polishing sheet 35 on a rotor 19 at the uniform pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an ultra-thin and thin conductive wire attached on a glass substrate or a silicon wafer, and a thin film uniformly attached to the periphery thereof and the upper layer thereof. The present invention relates to a flattening polishing method for polishing and removing a portion of the electric insulating layer protruding from the surface of a wiring board so as to be exposed from the electric insulating layer, and an apparatus therefor.

[0002]

2. Description of the Related Art As semiconductors become more highly integrated, larger in scale, and larger in area, wirings are becoming finer and multilayered. Wiring is formed by depositing wiring material or insulating material partially or entirely on the substrate, but if the multilayer wiring structure is stacked as it is, unevenness and steps will increase, causing the wiring to bend. Sparks and disconnections between upper and lower wirings are likely to occur.

In order to solve this problem, after forming a matrix of lower wiring, the space between the wirings is filled with an insulating film.
A method of flattening the surface and exposing and forming a matrix of upper wiring has been adopted. In this case, a lapping machine is usually used to flatten the surface. For example, a silicon wafer substrate having a small area of 6 inches (150 mm) has already been put to practical use.

[0005] The wiring board here is, as shown in FIG.
Before the flattening polishing work, the metal wiring 62 and the interlayer insulating film 63 adhere to the substrate 61, and there are protruding steps on the surface. As shown in FIG. When the abrasive sheet 35 is pressed against and polished, pressure is concentrated on the projections, and the projections can be selectively removed and flattened in the process of rotating and polishing the polishing tool (lap). .

If the polishing is performed using a soft polishing sheet so that the pressure distribution is equal over the entire surface of the substrate and the surface of the substrate follows the entire surface of the substrate so that the surface can be uniformly removed. By doing so, in a soft abrasive sheet, the pressure difference between the concave portion and the convex portion at the projecting step becomes small.

Therefore, in order to remove the wiring step, it is preferable to use a hard sheet as described above. Depending on the situation, it is preferable to remove both of the protrusions (to remove the projecting step and to polish the entire surface of the substrate). In order to satisfy the condition (1), an appropriate elastic sheet is selected and used.

[0007]

As the area of the substrate to be polished increases, the area of the lap, which is a polishing tool, increases, and a large-area lap having good flatness over the entire surface can be manufactured. It becomes difficult. Further, the warpage of the substrate also increases, and when pressed against a soft elastic sheet, the sheet is greatly deformed, making it difficult to obtain a uniform sheet repulsive force. On the other hand, in the case of a harder sheet, the wrap surface cannot naturally follow the warpage of the substrate, and the surface pressure distribution becomes uneven.

That is, as described above, it is difficult to polish the entire surface of a large-area substrate by applying uniform pressure only by adjusting the elastic modulus of the polishing sheet. As another method, an elastic member is used as a holding member on the back surface of the substrate to maintain the warpage of the substrate. However, uniform holding with the elastic member has been difficult.

The present invention has been made based on the above circumstances, and measures the pressure distribution acting on the polishing contact surface in order to eliminate the non-uniformity of the pressure distribution over the entire surface of the substrate, which is a drawback of the conventional method. It is an object of the present invention to provide a method and an apparatus for flattening and polishing a wiring substrate so as to obtain a desired pressure distribution.

[0010]

Therefore, in the present invention,
During the polishing of the wiring board by the polishing sheet, the pressure distribution acting on the contact surface to be polished is measured, and the pressure applied to the contact surface of the wiring substrate to be polished is automatically adjusted from the pressure distribution so that a uniform surface pressure distribution is obtained. It is characterized by adjusting.

In order to realize this method, the flattening and polishing apparatus of the present invention is provided with a large number of pressure sensors and pressure means uniformly distributed and arranged in a region corresponding to the contact surface to be polished of the wiring substrate. The pressure of the corresponding pressurizing means is automatically adjusted based on the measurement value of the pressure sensor.

In this case, the pressure sensor and the pressing means are provided on the back side of the polishing sheet in a region corresponding to the contact surface to be polished of the wiring board, or the contact surface to be polished of the wiring substrate to be polished and the polishing Any of a large number of load pieces and a large number of pressure sensors may be arranged on either side of the back of the seat. Further, the pressure sensor may be of an electrostrictive type, and the pressing means may be constituted by a piezo actuator or a micro screw.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a typical configuration of the present invention, in which an elastic sheet 12 having a uniform thickness is coated on the opposite side of the polished contact surface of the glass substrate 11, that is, on the back surface side of the glass substrate 11. Above it, a number of pressure-sensitive sensors 13 are arranged vertically and horizontally at least in a region corresponding to the polished contact surface. Above it, pressing means for electrically feeding out a minute amount, for example, a pressing element 14 such as a piezo actuator is arranged corresponding to each pressure-sensitive sensor 13.

[0014] In this embodiment,
There is a plate-shaped rigid member 17 whose bottom surface is the same size as the substrate size. The glass substrate is sandwiched between the rotating body 19 on the polishing tool side and the plate member 17, and a number of senses are provided via the elastic polishing sheet 35. While the pressure sensor 13 senses the contact pressure of each local part, based on the information, the pressing element 14
Can be pressed against the polishing sheet 35 on the rotating body 19 with a uniform pressure.

The elastic sheet 12 is a protective sheet for preventing the back surface of the glass substrate from being damaged, and has a sufficiently soft elasticity so that local pressure does not directly act on the glass substrate. In addition, the pressure-sensitive sensor is, for example, a sensor material of which electric resistance changes due to strain on a surface of a flexible resin film or thin rubber, which is attached at a constant pitch by a printing means, and a large number of the substances are attached by pressure. The distortion of the substrate glass 11 is measured as an analog signal.

Further, the plate-like member 17 is made of a rigid material, serves as a fixed-side support surface for the pressing element 14, and also acts as a pressure weight during polishing. In this case, the thickness of the plate member 17 is changed and its weight is adjusted so that the contact surface pressure is usually 10 to 100 g / cm ² . As a result of the tips of the many pressing elements 14 pressing the back surface of the substrate 11, the substrate 11 is gently deformed, and the polishing sheet 35 is deformed according to this, thereby generating a repulsive force at the polishing interface.

In this case, a pressure difference is generated between the polishing sheet 35 and the polished contact surface of the glass substrate 11 due to the difference in the amount of expansion of each pressing element 14. The difference between the repulsive forces of the pressing elements 14 is detected by the pressure-sensitive sensor 13, and the pressure signal is transmitted to the lead 18.
1 and is sent to the data processing circuit section 16 on the rear side of the plate member 17. Then, the operating voltage of the pressing element 14 is changed so that each location has a desired pressure, and the forward and backward driving of the pressing element 14 is performed. In the figure, reference numeral 1
Reference numeral 5 denotes an internal power supply for electronic components.

The same operation and effect can be obtained even if the arrangement of the pressure sensor 13 and the pressing element 14 are reversed. Further, in FIG. 1, the pressure sensor 13 and the pressing element 14 are arranged in series on the back surface of the substrate 11, but the arrangement of both is one on the substrate 11 side and the other is on the polishing tool side. As described above, the same operation and effect can be obtained even when the components are separately installed.

When the glass substrate 11, which is a workpiece, is thick, it is difficult to deform, so that the distortion of the substrate 11 is reduced, and the pressure sensing accuracy of the pressure sensor 13 on the rear surface of the substrate becomes insufficient. Further, it becomes difficult to deform the glass substrate 11 by the pressing element 14 arranged on the back surface of the substrate 11. In this case, it is possible to arrange the pressing element 14 and the pressure sensor 13 on the back side of the polishing sheet 35 which is a polishing tool. In this case, the polishing sheet 35 is preferably made of a thin elastic foamed polyurethane resin in a large amount. Due to this, since the deformation resistance is small, the deterioration of the pressure-sensitive accuracy is reduced. The expansion and contraction movement is sufficiently transmitted to the contact surface to be polished, and a pressure change can be generated.

FIG. 2 shows such a configuration, in which the pressing element 14 is fixed to the base 21 of the polishing tool by the fixing member 18 and the polishing sheet 35 is fixed by the fixing member 22. Further, a waterproof coat is applied to the back surface of the polishing sheet 35 to prevent the polishing liquid from entering the inside. The operations of the pressing element 14 and the pressure sensor 13 are the same as those in the embodiment of FIG. The glass substrate 11
In the case where the pressure sensor 14 is thin and easily deformed, the number of the pressing elements 14 and the pressure sensors 13 can be reduced, and the embodiment of FIG. 1 is optimal.

The pressing element (actuator) 14 includes an electrostrictive piezo element and a micro screw. When the relative movement between the workpiece and the tool is fast and high-speed response is required,
Using the former (the method of Fig. 1), when the movement of the tool is slow,
When the workpiece has a large warp and the required displacement of the pressing element 14 is large, it is preferable to use the latter having a large stroke (the method shown in FIG. 2).

The surface pressure distribution during polishing is indicated by the analog potentials of a large number of pressure sensors 13 and passed through an AD converter.
The data is input to the data processing circuit (computer) 16. In this case, a portion deviated greatly from the predetermined pressure is picked up, and the pressing element at the position is driven to approach the predetermined pressure. When the pressing element is a piezo, the displacement can be adjusted directly through a dedicated circuit. In the case of a fine movement screw, a pulse motor or the like directly connected to the screw is rotated by a small angle to feed the screw.

As another pressing means, as shown in FIG. 3, without using the pressing element (actuator) 14, a load piece 33 smaller than the size of the glass substrate 11 is used, and the weight of each load piece 33 or There is a method of changing the position on the substrate 11 to adjust the pressure distribution. Here, in the region of the glass substrate 11 within the holding disk 38, a large number of load pieces are placed on the substrate, the substrate 11 is gently deformed, and the lower elastic polishing sheet 35 is deformed, so that the repulsive force is reduced. To be born. This determines the pressure distribution at the polished contact surface.

A pressure distribution sensor 37 is provided below the polishing sheet 35. By performing a pressure distribution measurement, the degree of unevenness of the surface pressure acting on the substrate surface is quantitatively grasped. By adjusting the weight of the load piece of the part and the weight of the load piece of the high-pressure part, it becomes possible for each part to approach a predetermined surface pressure. In this embodiment, the same effect can be obtained by changing the position of the load piece on the substrate 11 instead of changing the weight of the load piece. Further, in order to further enhance the pressure measurement accuracy, it is effective to perform the measurement in a non-rotation stationary state of the polishing tool.

[0025]

【Example】

(Embodiment 1) A specific example for implementing the present invention will be described below. Here, on a glass substrate surface having an outer diameter of 330 × 258 mm and a thickness of 1.1 mm, a width of 20 μm,
A Cr wiring having a thickness of 0.3 μm is formed by vapor deposition at a pitch of 100 μm, and CVD-Si ₃ N ₄ is formed thereon, and a thickness:
It adhered uniformly at 0.7 μm. A sponge sheet having a thickness of 1 mm is provided on the back surface of the substrate glass, and a sponge sheet having a thickness of 0.1 mm is provided thereon.
1mm strain gauge resistor pressure sensor, on top of which
A piezo element with a diameter of 15 mm and a length of 20 mm
They were arranged at a pitch of 0 mm.

The thickness of the plate-shaped weight is adjusted, and the total load is 17 kg.
To make the average polishing pressure 20 kg / cm ² ,
The pressure value was detected by a pressure sensor, and the length of the piezo element was electrically adjusted so that the surface pressure became uniform.

(Embodiment 2) Ring zone on a polishing disk tool: 40
A pressure sensor and a piezo element as shown in FIG. 2 are arranged at a pitch of 25 mm at 0 to 200 mm, and a thickness of 1 m is placed thereon.
m is placed on the urethane polishing sheet and fixed to the outer peripheral edge of the tool disk. External dimensions: 100 × 100m on a polishing sheet
m, a glass substrate having a thickness of 1.1 mm is placed, and the pressure is set to 20.
Polishing is performed at g / cm ² . The pressure distribution adjustment is the same as in the first embodiment.

(Example 3) Outer diameter: 100 × 100 mm,
Thickness: 9 × 9 of equal weight on a 1.1 mm glass substrate
Row: 81 pieces, load rod of 7mm in diameter, 10m in length and width
Polishing was carried out at an average surface pressure of 20 g / cm ² with mounting at an m pitch.

[0029] As a result, the inside was removed almost uniformly from the inside diameter of 60 mm, but the removal was small until the outside diameter: 90 mm, and the removal was particularly large from the outside to the substrate edge.

Further, the surface pressure distribution is inward from the substrate edge: 5
mm, and the inner diameter is 60-90.
The surface pressure in the mm range was about half, 10 kg / cm ² . The weight of the load piece from the substrate edge to 5 mm inside was halved, and the weight of the load piece from 60 to 90 mm in diameter was doubled and polished to obtain a uniform removal within the diameter of 90 mm.

[0031]

According to the present invention, as described in detail above, a substrate having a large area having irregularities on its surface and having warpage can be obtained.
By making the polishing pressure distribution uniform, the entire surface can be uniformly polished and removed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a partial schematic configuration diagram showing a second embodiment of the present invention.

FIGS. 3A and 3B are a plan view and a schematic configuration diagram of a main part showing a third embodiment of the present invention. FIGS.

FIG. 4 is a schematic configuration diagram showing a mode of polishing by a conventional method.

FIG. 5 is a sectional view of a wiring on a substrate.

[Explanation of symbols]

 Reference Signs List 13 pressure sensor 14 piezo element 15 power supply 16 data processing circuit unit 19 polishing sheet rotating body 18, 22 fixing jig 32 rotating ring 33 load piece 35 polishing sheet 37 planar pressure sensor 40 substrate pressing plate member 61 substrate 62 metal wiring 63 insulation body

Claims (5)

[Claims] 1. During polishing of a wiring board by a polishing sheet,
Flattening polishing characterized by measuring a pressure distribution acting on a contact surface to be polished, and automatically adjusting a pressure applied to a contact surface to be polished of the wiring board from the pressure distribution so as to have a uniform surface pressure distribution. Method. 2. A plurality of pressure sensors and pressure means uniformly distributed and arranged in a region corresponding to a contact surface to be polished of a wiring board, and a corresponding pressure is applied based on a measurement value of the pressure sensor. A flattening and polishing apparatus characterized in that the pressing force of the means is automatically adjusted. 3. The flattening polishing apparatus according to claim 2, wherein the pressure sensor and the pressing means are provided on the back side of the polishing sheet in a region corresponding to the contact surface to be polished of the wiring board. . 4. A large number of load pieces and a large number of pressure sensors are disposed on any one of a plurality of load pieces and a plurality of pressure sensors on a surface to be polished of a wiring substrate to be polished and on a back side of the polishing sheet. The flattening polishing apparatus according to claim 2, wherein: 5. The flattening polishing according to claim 2, wherein said pressure sensor is of an electrostrictive type, and said pressing means is constituted by a piezo actuator or a micro screw. apparatus.