JP2010217469A - Wiring structure of spatial light modulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the reduction in arrangement pitch of optical modulation elements by facilitating drawing around lines for respective electrodes of the plurality of optical modulation elements. <P>SOLUTION: A wiring structure of a spatial light modulator having a device chip 5 wherein a plurality of optical modulation elements 6 made of an electro-optical crystal material are arranged in parallel with a prescribed pitch includes: a plurality of electrode pads 1 which are extended on one surface of the device chip 5 in a direction approximately orthogonal to the arrangement direction of the plurality of optical modulation elements 6 and each of which has one end electrically connected to a pair of electrodes 7 provided on opposite surfaces of each optical modulation element 6, which are parallel with the arrangement direction; a plurality of junction lines 2 which have formed on one surface of a support substrate 9 supporting the device chip 5 and have one end parts provided oppositely to the plurality of electrode pads 1 of the device chip 5; connection members 3 for electric flip-flop connection between respective electrode pads 1 and one end parts of respective junction lines 2; and a plurality of leader lines 4 which have one end parts electrically connected to the other end parts of the junction lines 2 and are formed on a circuit board 11 in many layers. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wiring structure of a spatial light modulation device having a device chip provided with a plurality of light modulation elements made of an electro-optic crystal material arranged at a predetermined arrangement pitch, and more specifically, wiring to each electrode of the plurality of light modulation elements This relates to a wiring structure of a spatial light modulation device that facilitates the routing of the light modulation elements and makes it possible to reduce the arrangement pitch of the light modulation elements.

  Conventionally, the wiring structure of this type of spatial light modulator has a plurality of individual electrodes arranged one-dimensionally on one surface and a common electrode facing all of the plurality of individual electrodes on the other surface. The electro-optic crystal substrate is formed, and each individual electrode is connected to a bonding pad connected to a driving circuit by wire bonding (for example, see Patent Document 1).

JP 11-174392 A

  However, since the wiring structure of such a conventional spatial light modulator is connected by wire bonding, the width of the individual electrodes is, for example, about 50 μm or less, and the interval between the individual electrodes is about 50 μm or less. In such a case, wire bonding is difficult, and adjacent wires may come into contact and short circuit. Therefore, the wiring structure using wire bonding has a limit in narrowing the arrangement pitch of the plurality of light modulation elements to about 100 μm or less.

  Therefore, the present invention addresses such problems, facilitates the routing of wiring to each electrode of a plurality of light modulation elements, and makes it possible to narrow the arrangement pitch of each light modulation element. An object is to provide a wiring structure of a device.

  To achieve the above object, a wiring structure of a spatial light modulation device according to the present invention includes a device chip having a plurality of light modulation elements made of an electro-optic crystal material arranged at a predetermined arrangement pitch, and the plurality of light A wiring structure of a spatial light modulation device that individually controls the modulation elements to turn on and off the emitted light, and extends on one surface of the device chip in a direction substantially orthogonal to the arrangement direction of the plurality of light modulation elements A plurality of electrode pads each having one end electrically connected to a pair of electrodes provided on opposing surfaces of the respective light modulation elements parallel to the arrangement direction, and formed on one surface of a support substrate that supports the device chip A plurality of relay lines provided with one end portions opposed to the plurality of electrode pads of the device chip, and a connection for electrically flip-chip connecting each electrode pad and one end portion of each relay line And wood, and electrically connected to one end portion to the other end of the trunk line, those having a plurality of lead lines which are multi-layered on the circuit board, the.

  With such a configuration, a pair of electrodes provided on one surface of the device chip is provided so as to extend in a direction substantially orthogonal to the arrangement direction of the plurality of light modulation elements, and provided on the opposing surfaces of the light modulation elements parallel to the arrangement direction. Connects a plurality of electrode pads, one end of which is electrically connected to each other, and a plurality of relay lines formed on one surface of the support substrate that supports the device chip, with one end facing the plurality of electrode pads of the device chip. Electrically flip-chip connected with a member, one end of multiple lead wires formed in multiple layers on the circuit board is electrically connected to the other end of the relay wire, and multiple light modulation elements are individually driven and controlled Turn the light on and off.

  The device chips are arranged in a plurality of rows at a predetermined arrangement pitch on the support substrate so that the plurality of light modulation elements are arranged in a substantially straight line. As a result, a plurality of light modulation elements are arranged at a predetermined arrangement pitch so that the plurality of light modulation elements are arranged in a substantially straight line on the support substrate, and each light modulation element of the device chip arranged in a plurality of rows alternately is turned on / off. .

  Further, the device chip is formed such that both end edges parallel to the arrangement direction of the plurality of light modulation elements are higher than the height of the plurality of light modulation elements, and a pair of the light modulation elements is formed on the upper surface of each edge. An electrode pad electrically connected to the electrode is formed and supported on the transparent and flat support substrate. Thus, the device chip is formed so that both end edges parallel to the arrangement direction of the plurality of light modulation elements are higher than the height of the plurality of light modulation elements, and a pair of light modulation elements is formed on the upper surface of each edge. An electrode pad that is electrically connected to the electrode is formed so that the end face of each light modulation element is separated from the surface of the support substrate even if it is placed on a transparent and flat support substrate.

  Furthermore, the support substrate is formed with through holes having a size corresponding to the plurality of light modulation elements of the device chip. Accordingly, a plurality of light modulation elements of the device chip can be inserted through the through holes formed in the support substrate.

  The connecting member is a solder ball. Thereby, each electrode pad and one end part of each relay line are electrically connected by the solder ball.

  According to the first aspect of the present invention, the electrode pad of the device chip having one end connected to the plurality of light modulation elements and the relay line of the support substrate are flip-chip connected by the connecting member, and the end of the relay line is connected to the circuit. Since it is connected to the lead line formed in a multilayer on the substrate, it is possible to easily route the wiring to each electrode of each light modulation element. Therefore, the arrangement pitch of each light modulation element can be reduced to, for example, 100 μm or less.

  In addition, according to the second aspect of the present invention, it is possible to interpolate between a plurality of device chips in the first column with device chips in another column. Therefore, if the spatial light modulator configured in this way is applied to an exposure apparatus that exposes an object to be exposed while transporting it in one direction, a precise exposure pattern can be formed.

  Further, according to the invention of claim 3, the device chip can be disposed on the transparent and flat support substrate, and the manufacture of the spatial light modulation device is facilitated. In addition, since each end face of the plurality of light modulation elements of the device chip is separated from the flat support substrate surface, no external stress acts on each light modulation element. Therefore, switching characteristics with high S / N can be obtained.

  Furthermore, according to the invention according to claim 4, even in the case of a device chip formed by projecting only a plurality of light modulation elements, each light modulation element can be supported in a state of being inserted into the through hole. it can. In this case, since each light modulation element is inserted into the through hole of the support substrate, external stress does not act on the light modulation element, and switching characteristics with high S / N can be obtained. In addition, since each light modulation element is embedded in the through hole of the support substrate, impact resistance is increased, and damage to the device chip due to external impact can be suppressed.

  According to the fifth aspect of the present invention, the device chip is self-centered (self-aligned) by the surface tension action of the molten solder ball, and the device chip can be appropriately arranged at a predetermined position of the support substrate. it can. Therefore, since it is not necessary to perform alignment between the device chip and the support substrate in advance with a microscope or the like, the spatial light modulator can be easily manufactured.

It is a principal part expanded sectional view which shows embodiment of the wiring structure of the spatial light modulation apparatus by this invention. It is a four-plane figure which shows the device chip | tip of the said spatial light modulation apparatus, (a) is a top view, (b) is a right view, (c) is a bottom view, (d) is a front view. It is explanatory drawing which shows the various forms of the electrode pad formed in the said device chip. It is a top view which shows the support substrate of the said spatial light modulation apparatus. It is a top view which shows the wiring board of the said spatial light modulator. It is the sectional view on the AA line of FIG. It is a front view which shows the other form of a device chip. It is sectional drawing which shows the state which has arrange | positioned the device chip of FIG. 7 on the flat support substrate. It is a figure which shows the other form of a device chip | tip, and is sectional drawing which shows the state arrange | positioned on the flat support substrate.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an enlarged sectional view of an essential part showing an embodiment of a wiring structure of a spatial light modulator according to the present invention. This wiring structure has a device chip having a plurality of light modulation elements made of an electro-optic crystal material arranged at a predetermined arrangement pitch, and individually controls driving of the plurality of light modulation elements to turn on and off the emitted light. The wiring structure of the spatial light modulation device is composed of an electrode pad 1, a relay line 2, a connecting member 3, and a lead wire 4.

  As shown in FIG. 2, the electrode pad 1 is formed by processing one surface of a device chip 5 made of an electro-optic crystal material having a strip shape in plan view, and arranging them at a predetermined arrangement pitch in the major axis direction, for example, a pitch of 100 μm or less. One end is electrically connected to each of the pair of electrodes 7 provided on the opposing surfaces of the light modulation elements 6 extending in a direction substantially orthogonal to the arrangement direction of the plurality of formed light modulation elements 6 and parallel to the arrangement direction. A known film forming technique such as vapor deposition, sputtering, or plating is applied to the bottom surface 8a of the excision part 8 which is excised from the both sides by a predetermined depth while leaving a predetermined width on the major axis of the device chip 5. It is provided by applying.

  This electrode pad 1 is applied by selecting at least one form from various forms as shown in FIG. 3, for example. Here, (a) of the figure is provided with one pad portion 1a having a size capable of arranging one solder ball (connection member 3) to be described later. Further, FIGS. 7B and 7C are provided with a plurality of pad portions 1a having a size capable of arranging one solder ball. Further, FIG. 4D is provided with a pad portion 1b having a size capable of arranging a plurality of solder balls in the extending direction and a dummy pad 1c electrically separated from the pad portion 1b. is there. FIG. 5E shows a plurality of pad portions 1b having a size capable of arranging a plurality of solder balls in the extending direction. Further, FIG. 5F shows a combination of a pad portion 1b having a size capable of arranging a plurality of solder balls in the extending direction and a pad portion 1a having a size capable of arranging one solder ball. Is. FIG. 6G shows a plurality of pad portions 1d having the same circular shape as the cross-sectional shape of the solder ball.

In this case, when the electrode pad 1 shown in FIGS. 3B to 3G is applied, a plurality of solder balls (connecting members 3) can be arranged in the extending direction of the electrode pad 1. Therefore, when the electrode pad 1 is connected to the relay line 2 formed on the support substrate 9 described later, the device chip 5 is self-centered (cell alignment) by the surface tension action of the molten solder ball, and the device chip. 5 is appropriately arranged at a predetermined position of the support substrate 9. In addition, the said pad parts 1a-1d are provided by appropriate quantity so that the self centering (cell alignment) effect of the device chip 5 may be acquired.

  On one surface of the support substrate 9 that supports the device chip 5, a plurality of relay lines 2 are formed to face the plurality of electrode pads 1 of the device chip 5. The plurality of relay lines 2 relay the electrical connection between a plurality of electrode pads 1 of the device chip 5 and a plurality of lead lines 4 of a multilayer circuit board 11 to be described later. As shown in FIG. 4, a plurality of rectangular shapes in plan view formed in four rows alternately in the major axis direction of a support substrate 9 made of a transparent substrate such as quartz having a plan view shape as shown in FIG. It is formed extending from both edge portions parallel to the long axis of the through hole 10 in a direction substantially orthogonal to the long axis of the support substrate 9. Alternatively, it may be formed in a fan shape on the left and right. And the edge part by the side of the through-hole 10 of the some relay wire 2 is formed along the major axis of the through-hole 10 with the same arrangement pitch as the arrangement pitch of the said several electrode pad 1. FIG.

  In this case, in FIG. 4, the through holes 10 in the second row from the left are formed so as to be shifted in the arrangement direction so as to interpolate between the adjacent through holes 10 in the first row. The holes 10 are arranged so that the plurality of light modulation elements 6 inserted into the through holes 10 interpolate between the plurality of light modulation elements 6 of the device chip 5 inserted into the first row of through holes 10. The fourth row of through-holes 10 are formed so as to be shifted in the direction, and the plurality of light modulation elements 6 inserted into the through-holes 10 are inserted into the second row of through-holes 10. They are formed so as to be shifted in the arrangement direction so as to interpolate between the elements 6 respectively.

  Therefore, an exposure apparatus is configured using a spatial light modulator formed by inserting a plurality of light modulation elements 6 of the device chip 5 into the through holes 10 of each row of the support substrate 9. A plurality of light modulation elements 6 inserted into each row of the through holes 10 are transferred for each column while conveying the object to be exposed from left to right in FIG. If the object to be exposed is overlapped and exposed individually at a predetermined timing, a dense exposure pattern can be formed.

  A connection member 3 is provided on the plurality of electrode pads 1 of the device chip 5. This connection member 3 electrically flip-chip-connects each electrode pad 1 of the device chip 5 and one end of each relay line 2 of the support substrate 9, and includes solder bumps (balls) and gold (Au) bumps. Etc. In the following description, a case where the connecting member 3 is a solder ball will be described.

  A plurality of lead wires 4 are formed on the circuit board 11 by electrically connecting one end portion to the other end portion of the relay line 2. The lead wire 4 is for electrically connecting the electrode 7 of each light modulation element 6 of the device chip 5 and an external drive circuit. As shown in FIG. 5, a plurality of lead wires 4 are formed on the support substrate 9. The circuit board 11 is formed with a plurality of through-holes 12 having a size slightly larger than the outer dimensions of the device chip 5 corresponding to the through-holes 10, and one end of each lead wire 4 on the through-hole 12 side. The part is exposed on the surface of the circuit board 11, and the other end is connected to a plurality of contact pins 14 of the connector 13 provided on the edge of the circuit board 11. 6 is a cross-sectional view taken along line AA in FIG. In this example, the lead lines 4 are formed in eight layers on the substrate 15 via the interlayer insulating film 16. In the figure, reference numeral 17 denotes a protective film.

Next, the production of the wiring structure of such a spatial light modulator will be described.
First, a device chip 5 is prepared in which one surface of a strip-like electro-optic crystal material in a plan view is processed and arranged in the major axis direction at a pitch of, for example, 100 μm or less to form a plurality of prismatic light modulation elements 6.

Such a device chip 5 can be formed as follows, for example. That is, the cut portion 8 is formed on one surface of the electro-optic crystal material having a strip shape in plan view by cutting away both sides thereof by a predetermined depth while leaving a predetermined width on the long axis. Next, a metal film is formed on the side surface and the bottom surface 8a of the cut portion 8 by applying a known film formation technique such as vapor deposition or sputtering. Subsequently, a separation groove 18 having a predetermined width is formed so as to intersect the major axis at a pitch of about 100 μm, for example, deeper than the depth of the cut portion 8, and is electrically separated from each other and arranged at a pitch of about 100 μm in the major axis direction. A plurality of light modulation elements 6 are formed. Thereafter, for example, gold (Au) is formed on the metal film by plating. As a result, the electrodes 7 are respectively formed on the opposing surfaces parallel to the arrangement direction of the plurality of light modulation elements 6. Further, any one of the shapes of the electrode pad 1 shown in FIG. 3 is selected, and the underlying metal film including, for example, gold (Au) deposited on the bottom surface 8a of the cut portion 8 is subjected to, for example, laser processing to pad. The parts 1a to 1d are formed. In this case, the device chip 5 deposits the high reflection film 20 on the outer side of the area 19 corresponding to the end face of each light modulation element 6 on the back surface 5a, and deposits the antireflection film in the area 19. Good.

  In addition, a plurality of through holes 10 having a rectangular shape in plan view having a size corresponding to the plurality of light modulation elements 6 of the device chip 5 are formed in four rows alternately in the major axis direction of the transparent substrate having a strip shape in plan view, It is formed extending from both edge portions parallel to the long axis of each through hole 10 in a direction substantially orthogonal to the long axis of the transparent substrate, and the end portion on the through hole 10 side is the same as the arrangement pitch of the plurality of electrode pads 1 A support substrate 9 provided with a plurality of relay lines 2 formed along the long axis of the through holes 10 at an arrangement pitch is prepared.

    Further, corresponding to the plurality of through holes 10 formed in the support substrate 9, a plurality of through holes 12 having a size slightly larger than the outer dimensions of the device chip 5 are formed in the circuit board, and the through holes 12 side are formed. A circuit board 11 having a plurality of lead wires 4 formed in multiple layers with one end exposed on the surface and the other end connected to a plurality of contact pins 14 of a connector 13 provided at an edge of the circuit board. Prepare.

  Next, the lead wire 4 forming surface of the support substrate 9 is placed on the support table with the upper surface facing upward. In addition, the device chip 5 in which the solder balls 3 are attached to the pad portions 1 a to 1 d of the plurality of electrode pads 1 by a known technique is inserted into the through holes 10 of the support substrate 9. And placed on the support substrate 9.

  Subsequently, both the support substrate 9 and the device chip 5 are irradiated with infrared rays using, for example, an infrared lamp to melt the solder balls 3. As a result, the device chip 5 is self-centered (self-aligned) by the surface tension action of the melted solder ball 3, and each device chip 5 is appropriately arranged at a predetermined position of the support substrate 9. At the same time, the relay line 2 of the support substrate 9 and the electrode pad 1 of the device chip 5 are electrically connected via the solder ball 3.

  Subsequently, an anisotropic conductive member 21 such as an anisotropic conductive film or anisotropic conductive paste is formed on the end of the relay wire 2 formed on the support substrate 9 on the side opposite to the end of the through hole 10 side. Adhere. And after aligning the through-hole 12 of the circuit board 11 with the device chip 5 on the support substrate 9, the circuit board 11 is press-contacted to the support substrate 9, and the adherend part of the anisotropic conductive member 21 is heated simultaneously. Both substrates 9 and 11 are thermocompression bonded. As a result, the lead wire 4 of the circuit board 11 and the relay line 2 of the support substrate 9 are electrically connected via the anisotropic conductive member 21 and the boards 9 and 11 are joined.

  In this way, a wiring structure of the spatial light modulator is completed in which the lead wire 4 of the circuit board 11, the relay line 2 of the support substrate 9, and the electrode pad 1 of the device chip 5 are electrically connected to each other. As a result, it is possible to individually supply a drive voltage to each electrode 7 of the plurality of light modulation elements 6 from an external drive circuit.

  FIG. 7 is a front view showing another form of the device chip 5. The device chip 5 has both end edges parallel to the arrangement direction of the plurality of light modulation elements 6 higher than the height of the plurality of light modulation elements 6, and a pair of light modulation elements 6 on the upper surface of each edge. An electrode pad 1 electrically connected to the electrode 7 is formed.

Such a device chip 5 can be formed as follows. That is, the cut portion 8 having a predetermined depth parallel to the long axis is left on one surface of the electro-optic crystal material having a rectangular shape in plan view, leaving a predetermined width on the long axis and a predetermined width at both ends parallel to the long axis. Form. Next, at least the convex portion 22 on the long axis sandwiched between the two cut portions 8 is shielded, and an inorganic material 23 such as SiO _{2 is} deposited from the one surface side of the electro-optic crystal material by sputtering or the like. The convex portion 24 at the edge is formed to be higher than the convex portion 22 on the long axis. Subsequently, the upper surface of the convex portion 22 on the major axis is shielded, and a known film formation technique such as vapor deposition or sputtering is applied to the side and bottom surfaces of the two cut portions 8 and the convex portions 24 at both end edges. To form a metal film. Further, a separation groove 18 (see FIG. 2) having a predetermined width is formed deeper than the depth of the cut portion 8 at a predetermined pitch so as to intersect the long axis, and is electrically separated from each other and aligned at a predetermined pitch in the long axis direction. A plurality of light modulation elements 6 are formed. Thereafter, for example, gold (Au) is formed on the metal film by plating. As a result, the electrodes 7 are respectively formed on the opposing surfaces parallel to the arrangement direction of the plurality of light modulation elements 6, and one end portion is electrically connected to the electrode 7 on the convex portion 24 at both end edges, and the electrode pad 1 is formed.

  As shown in FIG. 8, such a device chip 5 can be disposed on a support substrate 9 made of a flat transparent substrate in which the through-hole 10 is not formed, and the manufacture of the spatial light modulator is facilitated. . In this case, since the end face 6a of the light modulation element 6 is separated from the surface 9a of the support substrate 9, external stress does not act on the light modulation element 6 and birefringence abnormality does not occur. . Therefore, the contrast of the emitted light is high when the light modulation element 6 is turned on / off, and switching characteristics with good S / N can be obtained.

  FIG. 9 is a view showing still another form of the device chip 5, and is a cross-sectional view showing a state in which the device chip 5 is arranged on a flat support substrate 9. As shown in the figure, the device chip 5 is electrically connected to the electrode pad 1 on the surface (back surface 5 a) opposite to the surface on which the light modulation element 6 is formed and one end to the electrode 7 of the light modulation element 6. Let it form. Thus, the device chip 5 is arranged on the support substrate 9 made of a flat transparent substrate in which the through hole 10 is not formed, and the electrode pad 1 of the device chip 5 and the relay line 2 of the support substrate 9 are connected to the solder ball 3. Can be electrically connected.

  In the above-described embodiment, the case where a plurality of device chips 5 are arranged in four rows has been described. However, the present invention is not limited to this, and one elongated chip having a large number of light modulation elements 6 arranged in a straight line. Or a plurality of device chips 5 arranged in a straight line, or a plurality of device chips 5 arranged in two rows.

  In the above embodiment, the case where the support substrate 9 is made of a transparent substrate has been described. However, the present invention is not limited to this, and if the through hole 10 is formed corresponding to each light modulation element 6 of the device chip 5. For example, the support substrate 9 may not be a transparent substrate.

DESCRIPTION OF SYMBOLS 1 ... Electrode pad 2 ... Relay wire 3 ... Solder ball (connection member)
DESCRIPTION OF SYMBOLS 4 ... Lead wire 5 ... Device chip 6 ... Light modulation element 7 ... Electrode 9 ... Support substrate 10 ... Through-hole 11 ... Circuit board

Claims (5)

A spatial light modulation device having a device chip having a plurality of light modulation elements made of an electro-optic crystal material arranged at a predetermined arrangement pitch, and individually driving and controlling the plurality of light modulation elements to turn on and off the emitted light The wiring structure of
One end of each of the pair of electrodes provided on one surface of the device chip extending in a direction substantially orthogonal to the arrangement direction of the plurality of light modulation elements and provided on the opposing surface of each of the light modulation elements parallel to the arrangement direction. A plurality of electrically connected electrode pads;
A plurality of relay lines formed on one surface of the support substrate for supporting the device chip, and having one end portion opposed to the plurality of electrode pads of the device chip;
A connection member for electrically flip-chip connecting each electrode pad and one end of each relay line;
A plurality of leader lines formed in a multilayer on the circuit board by electrically connecting one end to the other end of the relay line;
A wiring structure for a spatial light modulator, comprising:   2. The device chips are arranged in a plurality of rows at a predetermined arrangement pitch on the support substrate so that the plurality of light modulation elements are arranged in a substantially straight line, and arranged in a plurality of rows alternately. Wiring structure of the spatial light modulation device.   In the device chip, both end edges parallel to the arrangement direction of the plurality of light modulation elements are formed higher than the height of the plurality of light modulation elements, and a pair of electrodes of the light modulation elements are formed on the upper surfaces of the edge parts. 3. The wiring structure for a spatial light modulator according to claim 1, wherein an electrode pad electrically connected to the substrate is formed and supported by the transparent and flat support substrate.   3. The wiring structure for a spatial light modulator according to claim 1, wherein the support substrate is formed with a through hole having a size corresponding to the plurality of light modulation elements of the device chip.   The wiring structure of the spatial light modulation device according to claim 1, wherein the connection member is a solder ball.

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